Based on the previous study, radiotherapy acts to devastate the nutritional status of patients, portending unfavorable post-treatment outcomes for cancer patients [20]. Especially for NPC patients the nutritional defect possesses a high prevalence and negatively disrupts the clinical performance of NPC patient. Therefore, it necessitates the general assessment of the nutritional status of NPC patients. GLIM criteria, as a well-popularized strategy to assess the nutritional status, get reasonably engaged with our study targeting NPC, extracting valued clinical guidelines for nutritional management and practice. Likewise, insightful research into this project may provide more evidence allowing for usability and effectiveness to GLIM criteria.
Undoubtedly, cancer, including NPC, characterize themselves as a cohort of consumptive diseases, which competitively and rapaciously seizure the nutrition due to the enormous energy demands resulting from uncontrollable self-reproduction and proliferation, as a result, heavily uneven distribution of nutrition tilted to tumor cells sparks the consumption of nutrition for cancer patients [21], rendering it understandable that the advanced stage of NPC accompanies the malnutrition before treatment from our result. According to several reports resembling our study, advanced NPC stage cancer patients are more likely to experience weight loss [10, 22]. Conceivably, locoregionally advanced tumor progresses for a long period, concurrent with wide deterioration and corresponding symptoms (like loss of appetite, swallowing, and chewing problems) featuring the impediment to caloric intake, which in the end plunges into nutrition shortage and induced malnutritional ultimately. Our study has uncovered the risk factors, including N stage, overall stage, and IC leading to malnourishment in the clinical practice, allowing for more sophisticated and reasonable managements or nutritional intervention in a preventive fashion.
As for the impact of IC on nutritional status, as an efficacious method to combat the tumor metastasis, it plays an indispensable role especially for advanced stage NPC when noting that 53.9% of NPC patients with IVA, and about 52.2% of patients received IC treatment as a necessary strategy in our study. In one sense, IC prolonged the survival of NPC patients [23, 24]. Nonetheless, the concomitant increased IC-induced toxicity much more likely courts the patients’ malnutrition simultaneously, which acts as a double-edged sword. Therefore, to balance the side effects and efficacy has been up to the agenda, improved IC treatment bearing more effectiveness and less toxicity is supposed to be considered and developed. Instructionally speaking, prior assessment of nutritional status and examination of nutritional signs for the NPC patients are ineluctably required. Early nutritional support such as enteral or parenteral nutrition figures as a strongly-recommended strategy before radiotherapy lest more difficult situations occur to the patients.
According to the previous studies [4, 12], radiotherapy undermines nutrition status, our result of increased prevalence of malnutrition on NPC along with radiotherapy conforms to this observation. The disruptive effect on the tumor and normal cells from radiotherapy incentivizes the impedimental process, leading to the patients’ physical feebleness. On the other hand, released substrates or chemicals from shattered cells and exposed antigens on the targeted cells induce immune responses and inflammation, leading to conclusively the high prevalence of malnutrition during radiotherapy [25-27]. Therefore, radiotherapy would aggravate the NPC patients’ nutritional status unmistakably, and the careful management of NPC patients’ nutrition appeared critical and indispensable in the case declined nutritional status concomitant with radiotherapy heavily compromise the outcomes of patients.
According to the GLIM criteria, if there is one criterion belonging to phenotypic and etiologic criteria respectively, it will denote malnutrition. Compared to a simple parameter or tool used to assess the nutritional status, GLIM criteria to some degree cover the specific information depicting the differed characteristics of patients; therefore, it might be more comprehensive. The different combinations of phenotypic GLIM criteria, weight loss, BMI, ASMI, and FFMI, demonstrated the polarized incidence of malnutrition. Low BMI contributed to the least proportion of malnutrition meaning the lowest sensitivity. On the other hand, weight loss >5% contributed to maximum proportion displaying the highest sensitivity and lowest specificity, and FFMI generally held the second place in sensitivity.
However, weight alteration as a standard to assess the nutritional status displays the shortcomings and becomes easily influenced by many confounding factors because of its widely embraced contents, for an instance, loss of skeletal muscle and increased adipose tissue would possibly amount to the stable weight, masking the objective situations [28]. Therefore, instead of the simple weight-related evaluation, body composition parameters, such as FFM and ASM, release more precise and relevant information to detect and monitor nutritional status [29]. In contrast to weight evaluation, FFMI stays relatively impervious to many other factors and holds considerable sensitivity. Taking clinical practice for nutritional management into account, patients who keep under the malnutritional risk must be screened out and monitored closely as early as possible. Missing any patient with malnutritional risk would be disfavored, therefore, FFMI, compared to other criteria, is of much practicality, to spot as many patients under malnutrition as possible.
Utilization of an effective method to improve FFM and FFMI before radiotherapy may reduce the therapy complications. Nutrition and exercise are the two main ways to improve FFM and FFMI [30]. Sufficient energy supply was able to maintain skeletal muscle mass during radiotherapy. Therefore, rational and effective dietary advice and nutrition intervention should be considered. Besides, physical exercise is another approach to gain skeletal muscle. Lonbro et al.[31]demonstrated that resistance of training effectively increased lean body mass in head and neck cancer patients undergoing radiotherapy. However, there is no long-term intervention and optimal diet guidance to maintain SM and compensate the metabolic consumption for NPC patients with low FFMI before radiotherapy.
Nutritional status involves inseparably with the cancer prognosis and subsequent progress, as evidenced in several studies that weight loss portends the poor outcomes of patients to some extent [32, 33]. Essentially, malnutrition evidently causes the decline of patient life-related conditions including the metabolic levels represented by anabolic hormones and tolerance to diseases due to compromised immunity, which associates with the constant downregulation of released inflammatory cytokines. As a result, patients with malnutrition become incompetent to cancer progression and suffer from the shortened survival period [34, 35]. Hong et al. [11] assessed the nutritional status by modified nutritional index, consequently elucidating that malnutrition relates to worse 5-year OS (61.8% vs 77.1%, p=0.02). Also, a meta-analysis study from another angle revealed the potential concatenation binding malnutrition and survival, indicating that NPC patients with low prognostic nutritional index (PNI) had worse PFS and OS [36]. Partly Consistent in our study, malnutrition of NPC patients contributed to shorter PFS, and meaningfully, advanced efforts are required for the more in-depth research on survival period and malnutritional status. Notwithstanding, the consistent finding of the relationship between malnutrition and OS failed to show in our study, which is presumably ascribed to the inadequate follow-up duration which should have been longer because NPC patients have a long survival period.
We have to admit that several limitations in our study. Evidently, our study belongs to the retrospective study and some information is likely to be omitted or disinformed, instead all relevant data would be closely observed and collected in prospective study. For an instance, C-reaction protein, which denotes the inflammation state counted in etiologic criteria of GLIM criteria, unfortunately appeared missing in our study due to its unnecessariness in radiotherapy department. Besides, insufficient number of patients collected may also affect the results, which would otherwise drive the outcomes more significant like in survival analysis and unveil some other hidden findings.