Effects of Photobiomodulation and Bethanechol Chloride Treatment on Salivary Composition and Flow Rate in Head and Neck Cancer Patients Undergoing Radiotherapy

doi:10.21203/rs.3.rs-4650778/v1

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Research Article

Effects of Photobiomodulation and Bethanechol Chloride Treatment on Salivary Composition and Flow Rate in Head and Neck Cancer Patients Undergoing Radiotherapy

https://doi.org/10.21203/rs.3.rs-4650778/v1

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Objective

To evaluate the efficacy of photobiomodulation therapy (PBMT) and bethanechol chloride (BC) on the quantity and quality of saliva in patients undergoing radiotherapy (RT) for head and neck cancer.

Methods

Saliva samples were collected from patients before and after RT, who were treated with PBMT or BC. Clinical parameters, including salivary flow rate (SFR), pH, xerostomia, and concentrations of macro and microelements in saliva, were assessed. Data were compared and analyzed using a self-organizing map.

Results

No significant changes were observed in SFR, pH, and xerostomia pre- and post-RT in both the PBMT and BC-treated groups. However, there was an increase in Cr levels in the BC group and a reduction in P levels in the PBMT group.

Conclusion

The results suggest that both PBMT and BC treatments can effectively mitigate the impacts of RT. The quality and quantity of saliva were maintained, potentially contributing to the preservation of patients' quality of life.

Xerostomia

radiotherapy

saliva

photobiomodulation

trace elements

Head and neck cancer (HNC) ranks as the seventh most common type of cancer worldwide. Radiotherapy (RT) stands as a primary clinical therapy for its treatment, often used in conjunction with chemotherapy or surgery [1,2]. When the salivary glands are within the irradiated area, various side effects emerge, including changes in the oral mucosa (oral mucositis), salivary glands (resulting in hyposalivation, dry mouth, and alterations in salivary composition), and taste buds (resulting in loss or alterations in taste) [3–5].

Xerostomia, commonly known as dry mouth, is one of the most prevalent symptoms experienced by patients undergoing and following RT for HNC [6–9]. Hyposalivation, or reduced saliva production, significantly increases the risk of oral infections and can lead to alterations in speech, taste, chewing, and swallowing, thereby profoundly impacting patients' quality of life during RT treatment [4,5,10]. Salivary glands are particularly sensitive to radiation, often resulting in damage during treatment. This damage can manifest as either temporary or permanent, leading to a loss of glandular function. [11].

Saliva is a complex biological fluid primarily composed of water, but it also contains organic components, proteins, peptides, polynucleotides, gingival fluid, and residual tissues [12,13]. Also, saliva contains an inorganic fraction, primarily composed of electrolytes such as sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), bicarbonates, and phosphates [13]. Most of these components are found in low-concentrations (trace level) and are participate in functions, such as protecting the teeth and oral tissues, controlling demineralization and remineralization, and buffering, allowing for the maintenance of homeostasis in the oral cavity [14,15].

On the other hand, the composition of saliva can vary due to different factors, therefore clinical conditions such as HNC, or RT treatment can impact and promote alterations in the salivary levels of components. Thus, these inorganic elements can be used as relevant markers to help diagnose dental damages such as caries, systemic alterations, and evaluation of disease progression [12]. Saliva may contain anticancer agents or cancer-associated agents that regulate various mechanisms, for example, Mg [16] or Cu and Zn found in HNC patients at lower levels [17].

In addition to changes in salivary composition, RT can affect salivary flow rate (SFR), which undergoes a significant reduction at the beginning of treatment [3–7,11,18,19]. A reduction of 37% compared to pre-RT levels has been reported, with partial recovery after 18 months [19]. There is still no fully effective therapy to prevent or treat RT-induced hyposalivation and xerostomia [18]. Among the reported therapeutic approaches aimed at alleviating hyposalivation symptoms are the use of artificial saliva, electrostimulation, drug therapies, including bethanechol chloride (BC), and photobiomodulation therapy (PBMT) [2,7,20–27]. BC is a cholinergic agonist that increases glandular function by stimulating muscarinic and nicotinic receptors, but it also appears to act on more selective receptors, not activating adrenoreceptors. Additionally, it has prolonged activity as it is more resistant to hydrolysis by cholinesterase and has a low cost compared to other medications, such as pilocarpine [18,20,21]. The use of BC alongside RT for salivary gland dysfunction treatment improves xerostomia symptoms, acting as a protective and glandular stimulant agent with fewer side effects [18,28]. PBMT has demonstrated efficacy by promoting modulation of cellular metabolism through increased mitochondrial ATP, which transforms the laser light into energy for the cell, resulting in an effect that stimulates the maintenance of salivary gland cells and contributes to saliva production maintenance [22,23,25,26,27,28].

Only a few studies have examined the effect of PBMT and BC treatments to alleviate the adverse effects of RT, particularly regarding hyposalivation and xerostomia. This study sought to assess the efficacy of these interventions in HNC treatment. Specifically, we aimed to evaluate the implementation of BC and PBMT and their effects on both the quantity and quality of saliva in individuals undergoing RT for HNC.

The sample was obtained by convenience, consisting of patients treated with ionizing radiation in the HNC treatment at Hospital Erasto Gaertner (Curitiba, PR, Brazil). Patients who underwent surgical removal of salivary glands were excluded. All patients received the same type of RT treatment, with no exclusions based on radiation dose, as most received very similar total doses. During the study period, patients were randomly allocated into two groups: PBMT or BC. Both treatments PBMT and BC started and finished in the same day of RT. In the PBMT group, patients underwent PBMT sessions (between 15 and 20) at a frequency of 2 to 3 sessions per week, as described in Schepanski et al. [27]. Application sites and specifications regarding power, wavelength, and irradiation time are described in Frame 1 and 2 [27]. In the BC group, the medication was administered in capsules (25mg) taken twice daily throughout RT treatment [21].

Frame 1

Application of extraoral PBMT comprising major salivary glands

Anatomical Region	Exposing	Wavelength	Dose per point
Parotid Glands	8 extraoral points	Infrared (808nm)	4J/point – 100mW (40 s/point)
Parotid Glands	10 intraoral points	Red (660nm)	0,5J/point − 100 mW (5 s/point)
Submandibular Glands	3 extraoral points	Infrared (808nm)	4J/point − 100mW (40 s/point)
Sublinguais Glands	3 intraoral points	Red (660nm)	0,5J/point − 100mW (5 s/point)

Frame 2

Application of intraoral PBMT comprising minor salivary glands

Anatomical Region	Exposing	Wavelength	Dose per point
Labial mucosa	4 intraoral points on the upper and lower mucosa	Red (660nm)	0,5J/point − 100 mw (5 s/point)
Fund of vestibule	4 intraoral points upper and lower	Red (660nm)	0,5J/point − 100 mw (5 s/point)
Soft palate	6 intraoral points	Red (660nm)	0,5J/point − 100 mw (5 s/point)
Tongue	4 intraoral points (each side)	Red (660nm)	0,5J/point − 100 mw (5 s/point)

Sample collection and clinical data

Variables such as sex, age, and tumor location/staging, as well as radiation dose, were obtained from patients' medical records. During treatment, patients received guidance on oral hygiene and mucosal hydration. For saliva sampling, patients were instructed to refrain from ingesting food or beverages, using lip cosmetics, smoking, or experiencing any physical stress one hour before the sample collection procedure [4]. Stimulated saliva samples were obtained according to Schepanski et al. [27], before the start of RT (pre-RT), and after the completion of all sessions (post-RT).

Stimulated salivary flow rate (SFR) and pH measurements

The stimulated SFR was obtained by measuring the volume and mass of saliva collected over a 5-minute collection period [29]. Salivary pH measurements were conducted immediately after sample collection, at room temperature, using a previously calibrated pH meter (Phtek, model PHS-3B, Curitiba, Brazil). Samples were labeled and stored at a temperature of -20°C.

Evaluation of xerostomia

The assessment of dry mouth sensation was conducted in the PBMT and BC groups in pre-and post-RT sessions and a visual analog scale (VAS) to measure this sensation. The VAS consisted of a numbered scale from 0 to 10, where 0 represented the absence or no sensation of dry mouth and 10 indicated a strong sensation of dry mouth [27,30].

Saliva elementary composition

The concentrations of the elements Al, As, Bi, Cd, Co, Cr, Cu, Li, Mn, Mo, Pb, Sb, Se, Sr, Ti, V, and Zn were determined using inductively coupled plasma mass spectrometry (ICP-MS, Agilent 7800, Agilent Technologies, Japan), as described before [27]. The concentrations of Ca, K, Mg, P, and S were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES, model 5110, Synchronous vertical dual view, Agilent Technologies, Australia). Detailed description of the analysis is described in SI Tables 2 and 3.

Data analysis by self-organizing map

The self-organizing map (SOM) analyzed concentrations of macro- and microelements in the saliva of patients from the PBMT and BC groups, both pre- and post-RT, alongside clinical parameters (VAS, SFR, and salivary pH). SOM analysis is described in SI S4. [31–37]

Statistical analysis

The data were analyzed for normal distribution using the Kolmogorov-Smirnov or Shapiro-Wilk tests. For data that followed a normal distribution, a two-way analysis of variance (ANOVA) was applied, followed by Bonferroni or Sidak post-hoc tests. Categorical variables were analyzed using the Chi-square test or Fisher's exact test. For data with non-normal distribution, the Kruskal-Walis’s test was used. The statistical analysis was performed at a 95% confidence level using Prism software 8 (GraphPad Software, United States).

In this study, 68 patients were initially included based on eligibility criteria. However, 8 patients were excluded during the study due to treatment interruption or death. The convenience sample comprised 60 patients with a history of HNC who were divided into two groups for PBMT treatment (n = 29) or BC treatment (n = 31).

The demographic data of the patients are presented in Table 1. The groups were fairly homogeneous regarding clinical variables, showing no statistical difference between them. Patient ages ranged from 25 to 85 years, with a mean of 60.5 years, and the majority were male (81.7%). The most common tumor site was the oral cavity, particularly the tongue for both groups, followed by the larynx and then the pharynx, including the nasopharynx, oropharynx, and palatine tonsils. Most cases of HNC were at advanced stages (III and IV).

Table 1

Demographic characteristics, radiation dose, tumor stage, and type of tumor location in the photobiomodulation therapy (PBMT) and bethanechol chloride therapy (BC) groups
	PBMT	BC
Variable	(n = 29)	(n = 31)	p-value
Age (mean ± SD) *	59.1 ± 14.3	61.6 ± 8.6	0.37
Sex. n (Male/Female) †	29 (22/7)	31 (27/4)	0.26
Smoking (n) †			0.36
Yes	11	12
Ex	11	14
Never	7	3
Alcohol intake (n) †			0.73
Yes	5	4
Ex	12	10
Never	12	15
Radiation dose (n) ‡			0.79
60 to 69	16	16
70	11	13
Unknown	2	–
Tumor stage †			0.92
I	5	5
II	6	5
III	8	8
IV	8	11
Unknown	2	–
Tumor location †			0.62
Larynx	7	11
Oropharynx	6	5
Oral cavity	16	15
Chemotherapy †			0.49
Yes	20	20
No	8	11
Unknown	1	–
* Student's t-test
† Chi-square test
‡ Fisher's exact test

Additionally, Table 2 shows that there was no significant alteration in pH and SFR in both pre- and post-RT, no significant difference was found regarding the treatment employed. There was approximately a 40% reduction for PBMT and 30% for BC SFR. Furthermore, xerostomia did not show a difference in dry mouth sensation for the pre-and post-PBMT and BC groups.

Table 2

Evaluation of salivary pH, salivary flow rate, and xerostomia in the photobiomodulation therapy (PBMT) and bethanechol chloride therapy (BC) groups, pre-and post-radiotherapy (RT)
	Condition			ANOVA
Variable	(RT)	PBMT	BC	(Variable)	F-value	p-value
Salivary flow rate	Pre-RT	0.89 ± 0.83	0.93 ± 0.63	Time	3.61	0.06
(mL/min) ^(a)	Post-RT	0.54 ± 0.61	0.65 ± 0.52	Treatment	0.33	0.56
				Interaction	1.55	0.21
pH ^(a)	Pre-RT	8.06 ± 1.18	8.13 ± 1.03	Time	2.90	0.09
	Post-RT	7.82 ± 1.32	7.74 ± 1.35	Treatment	0.01	0.94
				Interaction	0.25	0.61
Xerostomia	Pre-RT	2.44 ± 0.49	2.03 ± 0.36	–	–	0.14†
(VAS)^{(b, c)}	Post-RT	3.17 ± 0.50	3.48 ± 0.52	–	–
^a Mean ± standard deviation (SD)
^b Mean ± standard error (SE)
^c Visual analog scale
† Kruskal-Wallis’s test

Table 3 and Table 4 present the means (± standard deviation) for the inorganic components determined in saliva that showed significant statistical differences in the comparison between pre-and post-PBMT and BC groups. Most of the analyzed element’s levels (Al, As, Bi, Ca, Cd, Co, Cu, K, Li, Mn, Mg, Mo, Pb, S, Sb, Se, Sr, Ti, V, Zn) did not show a statistically significant difference concerning the evaluated time (pre-RT and post-RT) and regarding the treatment (PBMT or BC), with data presented in Table S4 (SI). There was a significant increase in Cr concentration for the BC group and a reduction in P for the PBMT group. Elements S and V (Table 4), after Dunn's post-hoc test, there was no significant difference between the determined concentrations in both treated groups pre-and post-RT.

Table 3

Comparison of groups showing statistical differences in chromium (Cr), phosphorus (P), sulfur (S), and vanadium (V) levels between the photobiomodulation therapy (PBMT) and bethanechol chloride (BC) groups, pre-and post-radiotherapy (RT)
Variable	Condition	PBMT	BC	p-value
Cr* ^(a)	Pre-RT	7.28 + 1.11 ^AB	5.57 + 0.58 ^A	0.03 (0.02†)
	Post-RT	12.35 + 4.86 ^AB	9.98 + 1.66 ^B
P‡ ^(b)	Pre-RT	134.50 ± 57.45 ^A	155.6 ± 69.1 ^AB	0.01
	Post-RT	92.58 ± 48.57 ^B	133.5 ± 92.9 ^AB
S‡ ^(b)	Pre-RT	98.03 ± 172.3	62.71 ± 42.07	?
	Post-RT	102.50 ± 76.92	88.91 ± 79.83
V* ^(a)	Pre-RT	23.20 ± 2.34	22.04 ± 1.70	0.04 (†)
	Post-RT	27.9 ± 341.0	28.16 ± 2.31
^a Mean ± standard error (SE)
^b Mean ± standard deviation (SD)

* Kruskal-Wallis’s test (non-normal distribution) and the †Dunn post hoc test showed non-significance.

‡ Two-way ANOVA and Sidak post hoc test at non-normal distribution.

^A Pre-RT

^B Post-RT

Table 4

Group comparison for the elements phosphorus (P) and sulfur (S) in the photobiomodulation therapy (PBMT) and bethanechol chloride (BC) groups, pre-and post-radiotherapy (RT)
	Condition			ANOVA
Variable	(RT)	PBMT	BC	(Variable)	F-value	p-value
P	Pre-RT	134.5 ± 57.45*	155.6 ± 69.11	Time	11.20	0.01
	Post-RT	92.58 ± 48.57*	133.5 ± 92.90	Treatment	6.86	0.01
				Interaction	0.49	0.48
S*	Pre-RT	98.03 ± 172.3	62.71 ± 42.07	Time	3.94	0.04
	Post-RT	102.5 ± 76.92	88.91 ± 79.83	Treatment	1.41	0.23
				Interaction	0.13	0.71
* There was no significant difference between the Two-way ANOVA and the Sidak post hoc test

The datasets pre- and post-RT for PBMT and BC were analyzed using SOM. The dataset comprised xerostomia (VAS scores), SFR, pH levels, and concentrations of macro- and microelements in 120 samples. SOM classified the samples into three groups (A, B, and C), as shown in Fig. 1, with separation between pre-RT samples in group A and post-RT samples in groups B and C. Cluster discrimination was determined by Euclidean distance, as shown in the dendrogram in Figure S1 (SI). Furthermore, the SOM component planes associated the sample grid positions on the map with the variation of each variable, as demonstrated in Fig. 1B. The U-matrix showed high-similarity among all samples, with low unified distance values indicated in shades of blue. No variable stood out in separating the groups. VAS values were generally high for Group C and low for Group B, while pH was associated with group A.

Squamous cell carcinoma (SCC) is the most common malignant neoplasm in HNC and is typically observed in individuals over 40 years of age and males have a 2 to 4 times higher risk of developing the neoplasm [38,39]. In the treatment of HNC, RT is one of the most common treatment modalities, and the dose of radiation used influences the occurrence of side effects due to changes in oral cavity tissues and salivary gland function [5,39].

In this study, 64% of patients were in more advanced tumor stages (III and IV), with the majority receiving a dose between 60 to 69 Gy, and the average total RT dose was 66.3 Gy, typically distributed over 33 fractions. An average dose of 15 Gy results in minimal reduction in salivary gland function [41]. However, this loss gradually increases with the applied dose, and doses exceeding 40 Gy impact reducing salivary gland function. Conversely, radiation doses surpassing 60 Gy generally lead to permanent salivary gland hypofunction, while doses ranging between 30 and 50 Gy may cause irreversible xerostomia [40].

Hyposalivation emerges as the primary consequence affecting all patients undergoing RT for HNC, as the salivary glands are directly exposed to the radiation beam [6, 7]. This reduction in SFR sets off a chain of consequences, including an increased incidence of cavities, speech and eating difficulties, as well as alterations in taste [3–5]. In terms of SFR, our study's findings indicate that both treatments effectively mitigate the impact of RT in HNC treatment. The PBMT group showed a 40% non-significant reduction in SFR, while in the BC group, it was 30%. Despite this reduction compared to the pre-RT stage, it remained lower than what has been reported in other studies, where reductions of up to 63% in post-RT patients were documented [19].

Therapeutic strategies aimed at alleviating the sequelae of reduced salivary flow rate in patients undergoing cancer treatment can significantly improve oral health and patient quality of life. To our knowledge, this is the first study to evaluate PBMT and BC as therapeutic options for managing hyposalivation and xerostomia during RT, and both have shown effectiveness.

BC is a carbamic ester of β-methylcholine resistant to cholinesterase action, thus having a longer duration of effect compared to other sialogogues. Recommended doses, between 25 to 200 mg per day, are used without observed effects on heart rate, blood pressure, or peripheral circulation. In this study, a dose of 25 mg twice daily was used to minimize any adverse effects [20]. Previous studies by Jham et al. [20] evaluated the clinical effect of BC during RT compared to artificial saliva, and similarly to Jaguar et al. [21], who compared it to placebo, the prophylactic use of BC was effective in reducing salivary gland damage, thus significantly improving salivary parameters.

There was no statistically significant reduction in SFR, and no adverse effects were observed. Salivary stimulants such as BC offer a preferable treatment option for hyposalivation compared to saliva substitutes like artificial saliva because they stimulate natural saliva secretion from undamaged glands [7]. Consistent with findings in the literature, BC can be regarded as a medicinal option to reduce the risk of salivary gland hypofunction and xerostomia [26]. Another preventive measure for inadequate cellular renewal in salivary glands, resulting from damage caused by free radicals generated during RT, is PBMT, which provides beneficial energy for cells to remain active [23,28]. Also, to the recommendation from the World Association for Photobiomodulation Therapy (WALT) [42] for the use of PBMT as a means to prevent hyposalivation during RT, PBMT also appears to minimize radiation-induced hyposalivation [25]. The integration of PBMT into supportive care for patients undergoing antineoplastic treatment has demonstrated benefits for both patients and the healthcare system by reducing morbidity and associated costs [22].

In a study where PBMT was administered after the completion of RT treatment, no difference was found between the therapy group and the control group [4]. In another study, it was noted that PBMT did not significantly impact complaints of xerostomia in patients undergoing RT [43]. An important reason for the discrepancies in the results found may be related to variations in the protocols adopted for PBMT, especially concerning the timing and frequency of applications and the wavelengths used. These variations limit the assessment and direct comparison of results and clinical benefits.

Louzeiro et al. [25] indicate that wavelengths in the red region tend to increase SFR more significantly compared to wavelengths in the infrared (IR) region, particularly those exceeding 750 nm. However, conflicting findings emerged in another study, where patients receiving PBMT for 10 consecutive days using an 830 nm wavelength (IR) showed consistently higher saliva quantities, attributed mainly to its greater tissue penetration capabilities during treatment [23]. PBMT, besides being a simple, cost-effective, patient-friendly, and non-invasive method, contributes to improving local microcirculation and stimulating glandular cell proliferation, thereby enhancing cellular respiration, protein synthesis, ATP production, and intracellular calcium levels. These cellular effects of PBMT vary in intensity according to the energy supplied, yet the wide variability in study methodologies contributes to the diversity of results [25,28].

Radiation-induced xerostomia stands as the most commonly reported side effect, significantly impacting various aspects of long-term quality of life [2,6]. In assessing the severity of xerostomia, which complements SFR data, this study is noteworthy for observing no difference in xerostomia between the BC and PBMT groups. These findings suggest that the prophylactic use of BC and PBMT may play a pivotal role in alleviating complaints of xerostomia and hyposalivation during radiotherapy treatment.

The treatments proposed in this study didn't worsen the sensation of dry mouth in either the BC or the PBMT groups, which is crucial for maintaining oral health in patients. Cotomacio et al. [18] demonstrated an improvement in xerostomia, while Kavitha et al. [28] reported a significant enhancement in subjective oral dryness in 80% of patients. Both studies evaluated BC and they also noted no change in salivary pH. Interestingly, there was an increase in saliva pH post-RT, preserving its buffering capacity, often diminished due to radiation-induced injury to serous acini [28]. However, in this study, there were no pH changes observed at the evaluated times or between the two treatment modalities for hyposalivation. Maintaining the composition homeostasis of saliva is crucial for oral health preservation, although chemical changes occur during RT [44,45].

Furthermore, in this study, the quality of saliva remained unaltered, as most determined elements (Al, As, Bi, Ca, Cd, Co, Cu, K, Li, Mn, Mg, Mo, Pb, S, Sb, Se, Sr, Ti, V, and Zn) showed no significant difference pre- and post-PBMT and BC. However, significant changes were observed in the levels of Cr and P elements. SOM analysis revealed a similarity between saliva analyzed pre- and post-RT for both groups. While there was a division of pre- and post-RT samples into two groups, component planes emphasized the low variation in concentrations of determined elements in saliva for both evaluated treatments. No difference was determined between BC and PBMT treatment regarding the concentration of determined elements.

The SOM analysis unveiled a correlation between xerostomia (high VAS scores) and elevated concentrations of Ca and Mg, as well as associations with As and Ti concentration levels. These findings also correspond with low SFR values, potentially leading to higher Cd and Mg concentrations. Moreover, alterations in salivary As levels have been linked to smoking [46]. Cr, which presented a significant difference between groups, is recognized as a clinical factor in SCC progression. It generates oxygen-free radical species and activates apoptosis inhibition signaling pathways, fostering mutation accumulation that may favor microenvironmental changes promoting tumor progression [45]. This study observed increased Cr levels compared to pre-and post-BC, with no significant difference between pre-and post-PBMT. Considering smoking history, a primary risk factor for oral cancer prevalent among a significant percentage of patients in this study, it's noted that certain associated ions like Cr were found in higher proportions among ex-smokers, while absent in cancerous tissue samples from individuals who never smoked [46].

Conversely, essential elements for oral cavity homeostasis, such as Zn, did not exhibit a significant difference between the studied groups. Zn, alongside Ca and P, plays a crucial role in maintaining periodontal health and regulating rates of dental enamel mineralization. Decreased Zn levels might contribute to halitosis, taste alterations, and reduced salivary flow rate [44]. The SOM analysis illustrates the correlation between low Zn levels and diminished SFR, particularly noticeable in group C (post-RT).

Concerning the advantages and disadvantages of the therapies employed, one benefit of utilizing PBMT to prevent reduced SFR is its widespread use alongside RT for preventing and treating oral mucositis [22]. Therefore, the only additional requirement is the inclusion of exposure points in extraoral regions. Another positive aspect is its localized effect, and given that patients are already undergoing daily RT, they are conveniently present at the hospital for PBMT sessions.

As for BC treatment, the advantage lies in its potential for at-home use through orally administered tablets. However, limited studies are available on the use of BC for this purpose, and achieving results requires patient commitment, along with the consideration of medication costs. Despite these challenges, it is considered a promising option that may effectively improve hyposalivation and xerostomia [47]. A drawback is that patients are already prescribed multiple medications, and this option adds one more to their existing oncological treatment regimen.

Our findings demonstrate that there was no significant reduction in SFR or worsening of xerostomia symptoms with the use of both treatments during RT. Positive and safe results were observed after applying PBMT and/or BC medication to minimize the effects of RT on salivary glands. These treatments may effectively prevent the sensation of dry mouth and RT-induced hyposalivation, thereby improving the quality of life for patients undergoing HNC treatment.

Finally, it's essential to highlight the study's limitations. Firstly, there was no long-term follow-up of patients after the conclusion of radiotherapy, making it impossible to determine the long-term efficacy of therapies in preventing xerostomia and hyposalivation. Additionally, the small sample size, attributed to the high mortality rate among oncological patients, and the absence of a control group without clinical intervention were limitations of the study.

The results of this study demonstrate the efficacy of PBMT and BC treatments in alleviating the adverse effects of RT during HNC treatment. No significant changes were observed in SFR, pH, and xerostomia of patients pre- and post-RT in both treatments. Regarding inorganic components, a significant increase in Cr concentration levels was noted for the BC group, while a reduction in P levels was observed for the PBMT group. The SOM analysis indicated that all analyzed samples showed high similarity in the evaluated clinical parameters and variables, with no difference between PBMT and BC treatments. These findings highlight that both PBMT and BC can enhance the quality of life of patients undergoing RT treatment and help maintain the quantity and quality of saliva.

Author Contribution

NS: Conceptualization, Methodology, Investigation, Data curation, Roles/Writing - original draft, Visualization, Funding acquisition.• BM: Investigation.• RM: Software, Formal analysis.• FC: Software, Formal analysis, Resources, Writing - review & editing, Funding acquisition.• CA: Validation, Formal analysis, Resources.• RM: Validation, Formal analysis.• AN: Data curation, Formal analysis, Resources.• LS: Supervision, Project administration.• MA: Conceptualization, Methodology, Resources, Data curation, Writing - review & editing, Supervision, Project administration.

Acknowledgement

The FSC thanks the partial financial support was received from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brazil (CAPES) – Finance Code 001 and special thanks to Pharmacy Magistral for supplying Bethanechol.

Compliance with Ethical Standards:

Funding information: Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq/Brazil [Grant numbers 308178/2018-1 and 403839/2023-8], and the National Bank for Economic and Social Development – BNDES.

Conflict of Interest: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper

Ethical approval: This study was approved by the Human Research Ethics Committee of Hospital Erasto Gaertner (No. 4-931-012). Informed consent for study participation was obtained from all participants.

Ferlay J, Colombet M, Soerjomataram I, Parkin DM, Piñeros M, Znaor A, et al. (2021) Cancer statistics for the year 2020: An overview. Int J Cancer 149:778–89. https://doi.org/10.1002/ijc.33588.
Mercadante V, Hamad A Al, McCaul J, Nutting C, Harrington K, Carnell D, et al. (2024) Salivary Electrostimulation in the Treatment of Radiation Therapy–Induced Xerostomia (LEONIDAS-2): A Multicenter, Randomized, Double-Masked, Sham-Controlled, Phase 3 Trial. Int J Radiat Oncol Biol Phys 118:142–53. https://doi.org/10.1016/j.ijrobp.2023.03.047.
Simoes A, Campos L, Freitas PM, Eduardo CP, Nicolau J. (2009) Laser as a therapy for oral complications induced by chemotherapy and radiotherapy. J Bras Laser 2:18–23.
Saleh J, Figueiredo MAZ, Cherubini K, Braga-Filho A, Salum FG. (2014) Effect of Low-Level Laser Therapy on Radiotherapy-Induced Hyposalivation and Xerostomia: A Pilot Study. Photomed Laser Surg 32:546–52. https://doi.org/10.1089/pho.2014.3741.
Mercadante V, Al Hamad A, Lodi G, Porter S, Fedele S. (2017) Interventions for the management of radiotherapy-induced xerostomia and hyposalivation: A systematic review and meta-analysis. Oral Oncol 66:64–74. https://doi.org/10.1016/j.oraloncology.2016.12.031.
Jellema AP, Slotman BJ, Doornaert P, Leemans CR, Langendijk JA. (2007) Impact of Radiation-Induced Xerostomia on Quality of Life After Primary Radiotherapy Among Patients With Head and Neck Cancer. Int J Radiat Oncol Biol Phys 69:751–60. https://doi.org/10.1016/j.ijrobp.2007.04.021.
Malallah OS, Garcia CMA, Proctor GB, Forbes B, Royall PG. (2018) Buccal drug delivery technologies for patient-centred treatment of radiation-induced xerostomia (dry mouth). Int J Pharm 541:157–66. https://doi.org/10.1016/j.ijpharm.2018.02.004.
Karbach J, Walter C, Al-Nawas B. (2012) Evaluation of saliva flow rates, Candida colonization and susceptibility of Candida strains after head and neck radiation. Clin Oral Investig 16:1305–12. https://doi.org/10.1007/s00784-011-0612-1.
Borras JM, Barton M, Grau C, Corral J, Verhoeven R, Lemmens V, et al. (2015) The impact of cancer incidence and stage on optimal utilization of radiotherapy: Methodology of a population based analysis by the ESTRO-HERO project. Radiother Oncol 116:45–50. https://doi.org/10.1016/j.radonc.2015.04.021.
Millsop JW, Wang EA, Fazel N. (2017) Etiology, evaluation, and management of xerostomia. Clin Dermatol 35:468–76. https://doi.org/10.1016/j.clindermatol.2017.06.010.
Li Y, Li X, Pang R, Yang G, Tian M, Zhao T, et al. (2022) Diagnosis, Prevention, and Treatment of Radiotherapy-Induced Xerostomia: A Review. J Oncol 2022:1–15. https://doi.org/10.1155/2022/7802334.
Rosa LK, Costa FS, Hauagge CM, Mobile RZ, de Lima AAS, Amaral CDB, et al. (2021) Oral health, organic and inorganic saliva composition of men with Schizophrenia: Case-control study. J Trace Elem Med Biol 66:126743. https://doi.org/10.1016/j.jtemb.2021.126743.
Humphrey SP, Williamson RT. (2001) A review of saliva: Normal composition, flow, and function. J Prosthet Dent 85:162–9. https://doi.org/10.1067/mpr.2001.113778.
Ngamchuea K, Chaisiwamongkhol K, Batchelor-McAuley C, Compton RG. (2018) Chemical analysis in saliva and the search for salivary biomarkers – a tutorial review. Analyst 143:81–99. https://doi.org/10.1039/C7AN01571B.
Kubala E, Strzelecka P, Grzegocka M, Lietz-Kijak D, Gronwald H, Skomro P, et al. (2018) A Review of Selected Studies That Determine the Physical and Chemical Properties of Saliva in the Field of Dental Treatment. Biomed Res Int 2018:1–13. https://doi.org/10.1155/2018/6572381.
Saavedra J, Novo D, Mesko M, Uchoa Vasconcellos AC, Duarte da Silva K, Rojas Zuñiga G, et al. (2022) Comparison of Salivary Electrolytes Profile in Oral Potentially Malignant Disorders and Oral Squamous Cell Carcinoma. Asian Pacific J Cancer Prev 23:1031–9. https://doi.org/10.31557/APJCP.2022.23.3.1031.
Shetty S, Babu S, Kumari S, Shetty P, Hegde S, Karikal A. (2015) Status of trace elements in saliva of oral precancer and oral cancer patients. J Cancer Res Ther 11:146. https://doi.org/10.4103/0973-1482.137973.
Cotomacio C, Campos L, Simões A, Jaguar G, Crosato EM, Alves F. (2017) Influence of bethanechol on salivary parameters in irradiated patients. Med Oral Patol Oral Cir Bucal 22:e76–83. https://doi.org/10.4317/medoral.21395.
Lin A, Helgeson ES, Treister NS, Schmidt BL, Patton LL, Elting LS, et al. (2022) The impact of head and neck radiotherapy on salivary flow and quality of life: Results of the ORARAD study. Oral Oncol 127:105783. https://doi.org/10.1016/j.oraloncology.2022.105783.
Jham BC, Teixeira IV, Aboud CG, Carvalho AL, Coelho M de M, Freire AR da S. (2007) A randomized phase III prospective trial of bethanechol to prevent radiotherapy-induced salivary gland damage in patients with head and neck cancer. Oral Oncol 43:137–42. https://doi.org/10.1016/j.oraloncology.2006.01.013.
Jaguar GC, Lima ENP, Kowalski LP, Pellizzon AC, Carvalho AL, Boccaletti KW, et al. (2015) Double blind randomized prospective trial of bethanechol in the prevention of radiation-induced salivary gland dysfunction in head and neck cancer patients. Radiother Oncol 115:253–6. https://doi.org/10.1016/j.radonc.2015.03.017.
González-Arriagada WA, Ramos LMA, Andrade MAC, Lopes MA. (2018) Efficacy of low-level laser therapy as an auxiliary tool for management of acute side effects of head and neck radiotherapy. J Cosmet Laser Ther 20:117–22. https://doi.org/10.1080/14764172.2017.1376097.
Brzak BL, Cigić L, Baričević M, Sabol I, Mravak-Stipetić M, Risović D. (2018) Different Protocols of Photobiomodulation Therapy of Hyposalivation. Photomed Laser Surg 36:78–82. https://doi.org/10.1089/pho.2017.4325.
Angeli JLF, Rubio B, Kim BSM, Ferreira PA de L, Siegle E, Figueira RCL. (2019) Environmental changes reflected by sedimentary geochemistry for the last one hundred years of a tropical estuary. J Mar Syst 189:36–49. https://doi.org/10.1016/j.jmarsys.2018.09.004.
Louzeiro GC, Teixeira D da S, Cherubini K, Figueiredo MAZ, Salum FG, de Figueiredo MAZ, et al. (2020) Does laser photobiomodulation prevent hyposalivation in patients undergoing head and neck radiotherapy? A systematic review and meta-analysis of controlled trials. Crit Rev Oncol Hematol 156:103115. https://doi.org/10.1016/j.critrevonc.2020.103115.
Mercadante V, Jensen SB, Smith DK, Bohlke K, Bauman J, Brennan MT, et al. (2021) Salivary Gland Hypofunction and/or Xerostomia Induced by Nonsurgical Cancer Therapies: ISOO/MASCC/ASCO Guideline. J Clin Oncol 39:2825–43. https://doi.org/10.1200/JCO.21.01208.
[[27] Schepanski N, Costa FS, Machado EFM, Pacheco MN, Amaral CDB, Machado RC, et al. (2023) Evaluation of photobiomodulation therapy (PBMT) on salivary flow and composition in head and neck cancer patients undergoing radiation therapy. Oral Surg Oral Med Oral Pathol Oral Radiol. 23:S2212-4403(23)00742-3. https://doi.org/10.1016/j.oooo.2023.11.007.
Kavitha M, Mubeen K, Vijayalakshmi K. (2017) A study on Evaluation of efficacy of bethanechol in the management of chemoradiation-induced xerostomia in oral cancer patients. J Oral Maxillofac Pathol 21:459–60. https://doi.org/10.4103/jomfp.JOMFP_72_16.
Banderas-Tarabay JA, González-Begné M, Sánchez-Garduño M, Millán-Cortéz E, López-Rodríguez A, Vilchis-Velázquez A. (1997) Flujo y concentracion de proteinas en saliva total humana. Salud Publica Mex 39:433–41. https://doi.org/10.1590/S0036-36341997000500006.
Eisbruch A, Kim HM, Terrell JE, Marsh LH, Dawson LA, Ship JA. (2001) Xerostomia and its predictors following parotid-sparing irradiation of head-and-neck cancer. Int J Radiat Oncol Biol Phys 50:695–704. https://doi.org/10.1016/S0360-3016(01)01512-7.
INMETRO. Orientação sobre validação de Métodos Analíticos. 7o ed. Rio de Janeiro, Brasil: Instituto Nacional de Metrologia, Qualidade e Tecnologia; 2020.
AOAC. Appendix F – Guidelines for Standard Method Performance Requirements. In: Latimer GW, organizador. Off. Methods Anal. AOAC Int., Rockville: Oxford University PressNew York; 2023. https://doi.org/10.1093/9780197610145.005.006.
Astel A, Nikolov M, Christov V, Simeonova P, Simeonov V. (2010) Chemometric assessment of clinical data for diabetes mellitus 2 ype patients using self-organizing maps. J Environ Sci Heal Part A 45:560–8. https://doi.org/10.1080/10934521003595290.
Vatanen T, Osmala M, Raiko T, Lagus K, Sysi-Aho M, Orešič M, et al. (2015) Self-organization and missing values in SOM and GTM. Neurocomputing 147:60–70. https://doi.org/10.1016/j.neucom.2014.02.061.
Vesanto J. (1999) SOM-based data visualization methods. Intell Data Anal 3:111–26. https://doi.org/10.3233/IDA-1999-3203.
Vatanen T. Self-Organizing Map algorithm (SOM Toolbox 2.1) 2012.
Vesanto J, Himberg J, Alhoniemi E, Parhankangas J. (1999) Self-organizing map in Matlab: The SOM Toolbox. Proc. Matlab DSP Conf., Espoo, Finland: p. 35–40.
Argiris A, Karamouzis M V, Raben D, Ferris RL. (2008) Head and neck cancer. Lancet 371:1695–709. https://doi.org/10.1016/S0140-6736(08)60728-X.
Chamoli A, Gosavi AS, Shirwadkar UP, Wangdale K V, Behera SK, Kurrey NK, et al. (2021) Overview of oral cavity squamous cell carcinoma: Risk factors, mechanisms, and diagnostics. Oral Oncol 121:105451. https://doi.org/10.1016/j.oraloncology.2021.105451.
Pedersen AML, Sørensen CE, Proctor GB, Carpenter GH, Ekström J. (2018) Salivary secretion in health and disease. J Oral Rehabil 45:730–46. https://doi.org/10.1111/joor.12664.
Deasy JO, Moiseenko V, Marks L, Chao KSC, Nam J, Eisbruch A. (2010) Radiotherapy Dose-Volume Effects on Salivary Gland Function. Int J Radiat Oncol Biol Phys 76:S58–63. https://doi.org/10.1016/j.ijrobp.2009.06.090.
Robijns J, Nair RG, Lodewijckx J, Arany P, Barasch A, Bjordal JM, et al. (2022) Photobiomodulation therapy in management of cancer therapy-induced side effects: WALT position paper 2022. Front Oncol 12. https://doi.org/10.3389/fonc.2022.927685.
Ribeiro LN, Lima MH, Carvalho AT, Albuquerque RF, Leão JC, Silva IH. (2021) Evaluation of the salivary function of patients in treatment with radiotherapy for head and neck cancer submitted to photobiomodulation. Med Oral Patol Oral y Cir Bucal 26:e14–20. https://doi.org/10.4317/medoral.23912.
Uwitonze AM, Ojeh N, Murererehe J, Atfi A, Razzaque MS. (2020) Zinc Adequacy Is Essential for the Maintenance of Optimal Oral Health. Nutrients 12:949. https://doi.org/10.3390/nu12040949.
Assis ALEM, Archanjo AB, Maranhão RC, Mendes SO, de Souza RP, de Cicco R, et al. (2021) Chlorine, chromium, proteins of oxidative stress and DNA repair pathways are related to prognosis in oral cancer. Sci Rep 11:22314. https://doi.org/10.1038/s41598-021-01753-x.
Archanjo AB, Assis ALEM de, Oliveira MM de, Mendes SO, Borçoi AR, Maia L de L, et al. (2020) Elemental characterization of oral cavity squamous cell carcinoma and its relationship with smoking, prognosis and survival. Sci Rep 10:10382. https://doi.org/10.1038/s41598-020-67270-5.
Nakamura D, Pinto H, Elchin C, Berard L, Alves F, Antunes L, et al. (2023) Efficacy of bethanechol chloride in the treatment of radiation-induced xerostomia in patients with head and neck cancer: A systematic review and meta-analysis. Radiother Oncol 186:109715. https://doi.org/10.1016/j.radonc.2023.109715.

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Effects of Photobiomodulation and Bethanechol Chloride Treatment on Salivary Composition and Flow Rate in Head and Neck Cancer Patients Undergoing Radiotherapy

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