Pretreatment neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio to guide the treatment decision (radical surgery versus denitive chemoradiotherapy) for locally advanced squamous cell carcinoma located in the middle and upper esophagus

Background: Various inammatory biomarkers, such as the neutrophil lymphocyte ratio (NLR) and platelet lymphocyte ratio (PLR), have been well authenticated to predict clinical outcomes in numerous types of cancer. The optimal treatment for patients with locally advanced esophageal squamous cell carcinoma (ESCC) located in middle or upper region is still inconclusive. The aim of the study was to examine pretreatment NLR and PLR to select from radical surgery or denitive chemoradiotherapy (dCRT) for these patients. The linkage between pretreatment NLR / PLR and prognosis was also analyzed. Methods: NLR and PLR were calculated in 113 locally advanced ESCC located in middle or upper esophagus of patients who underwent radical surgery or dCRT between January 2014 and December 2019. A receiver operating characteristic curve was plotted to select the best cut-off value of NLR and PLR for predicting survival. A survival curve was plotted using the Kaplan–Meier method. Univariate and multivariate Cox regression analyses were applied to assess predictors for survival. Results: NLR and PLR was both associated with the extent of lymph node metastasis (NLR: P = 0.045; PLR: P = 0.002). Additionally, high PLR and recurrence with distant organs metastasis were closely related (P = 0.014), and NLR was related to the tumor stage (P = 0.043). The results of multivariate analysis revealed that NLR (> 2.07) and PLR (> 183.06) were independently associated with poor prognosis. It is noteworthy that surgery was associated with a superior OS compared with dCRT in the low NLR population (P = 0.045). Conclusions: Low pretreatment NLR patients made a decision to undergo radical surgery with a substantial therapeutic benet. Pretreatment NLR and PLR are independent predictors for patients with locally advanced ESCC located in the middle and upper esophagus who underwent radical surgery or dCRT.


Background
Esophageal cancer is the eighth most common malignancy and the sixth leading cause of cancer-related deaths worldwide (1)(2). China is the highest-risk region, where esophageal squamous cell carcinoma (ESCC) is most prevalent, with approximately 90% of all histological sub-types compared with developed nations (3). In contrast to lower esophageal cancer, middle and upper esophageal cancers are more aggressive and the stages at diagnosis are commonly locally advanced (4). The landmark Chemoradiotherapy for Esophageal Cancer Followed by Surgery Study (CROSS) trial has become preferred in locally advanced esophageal cancer. However, the patient population in the CROSS trial had cancers mainly located in the lower esophagus, and accounted for only 24% of patients with ESCC (5). Therefore, radical surgery or de nitive chemoradiotherapy (dCRT) has been adopted for the treatment of locally advanced ESCC located in the middle and upper esophagus and has become the standard modality recommended by most scholars (6)(7)(8)(9). Additionally, with the development of radiation technology, research into the use of intensity-modulated radiation therapy (IMRT) for esophageal cancer treatment has shown improved outcomes (10)(11). On the other hand, the decision to undertake surgery requires careful consideration for fear of high morbidity and mortality rates following thoracotomy and laparotomy in these patients (12)(13). For the moment, the optimal treatment for patients with locally advanced ESCC located in the middle or upper esophagus is still inconclusive. It would be valuable to identify useful biomarkers to select the patients who are most likely to bene t from surgery or dCRT.
A mounting body of evidence has revealed that a systemic in ammatory response has a vital role in cell proliferation, invasion and migration as well as the response to treatment (14)(15). Various clinical in ammatory biomarkers, such as the neutrophil lymphocyte ratio (NLR) and platelet lymphocyte ratio (PLR), have been well authenticated to predict clinical outcomes in numerous types of cancer (16)(17)(18)(19)(20)(21). Among these biomarkers, pretreatment NLR and pretreatment PLR can be easily measured and are inexpensive tests. Both of them have been veri ed to be linked with tumor prognosis in ESCC patients who receive esophagectomy or dCRT (21)(22). However, no study has reported the application of pretreatment NLR and pretreatment PLR to guide the treatment decision between esophagectomy and dCRT for locally advanced ESCC in middle or upper esophagus patients.
In the present study, the locally advanced ESCC located in the middle or upper esophagus of patients who received esophagectomy and dCRT in our hospital were retrospectively reviewed. The objective was to evaluate the application of pretreatment NLR and pretreatment PLR in selected patients for radical surgery or dCRT. We also analyzed the linkage between pretreatment NLR / PLR and progression-free survival (PFS) / overall survival (OS) in this subset of patients.

Patient selection
We retrospectively reviewed patients with locally advanced ESCC in middle or upper esophagus who were seeking a radical cure at Ningbo Medical Center Lihuili Hospital between January 2014 and December 2019. The inclusion criteria were: (1) a pathology diagnosis of ESCC; (2) tumors located in the middle or upper part of the esophagus; (3) received curative esophagectomy or dCRT; (4) surgery without preoperative adjuvant chemotherapy and/or radiotherapy; (5) previously untreated; (6) locally advanced status, stage T3/4 or N+, without distant metastasis or abdominal lymph node metastasis; (7) no chronic or acute in ammatory condition. A total of 113 patients were enrolled. The pretreatment stage was made on the basis of the results of esophagogastroscopy/endoscopic ultrasonography, computed tomography (CT) examination, barium swallow, and bone and positron emission tomography (PET) scans. The stage of patients with curative esophagectomy was replaced by the postoperative staged. The patients were classi ed based on the TNM staging system of the 7th American Joint Committee on Cancer (AJCC).

Data Collection And De nitions
Clinical characteristics and pathological ndings, including age, drinking history, smoking history and tumor length were carefully recorded. The following hematology indexes were evaluated up to 1 week before treatment: neutrophil count (× 10 9 /L), platelet count (× 10 9 /L) and lymphocyte count (× 10 9 /L). We de ned the NLR as the neutrophil count divided by the lymphocyte count. Similarly, PLR was calculated as the ratio of the platelet count to the lymphocyte count.

Treatment Protocol
Surgery group the operative procedure was a traditional right antero-lateral thoracotomy with laparotomy or thoracoscopic esophagectomy in the prone position. The safety of the resected proximal boundary of the esophagus was guaranteed by intraoperative histological analysis of a frozen section of the proximal margin. Four cycles of adjuvant chemotherapy were given after surgery. The chemotherapy regimen was platinum combined with paclitaxel once every 3 weeks per cycle.
Chemoradiotherapy group these patients were treated with IMRT to guarantee tumor coverage and safeguard adjacent normal organs. Delineation of target tumor volume depended on the examination, such as barium swallow, esophagogastroscopy, CT and PET scans. The gross target volume (GTV) was designated as the primary tumor and metastatic lymph nodes, while the clinical target volume (CTV) was de ned as the primary tumor plus a 3-4 cm expansion superiorly and inferiorly along the length of the esophagus. A 1 cm radial expansion, which should also include supraclavicular regions. The planning target volume (PTV) was de ned as the CTV expanded by 0.5-0.8 cm margins in all directions. A dose of 50 Gy (2 Gy/fraction, 5 days per week) was given to PTV, following a boost dose to GTV for an extra 10 Gy in 5 daily fractions. The concurrent chemotherapy regimen was platinum combined with paclitaxel or uorouracil once every 4 weeks per cycle. One or two courses of chemotherapy were performed during radiotherapy. Two or three cycles of adjuvant chemotherapy were followed by radiotherapy.

Follow-up Assessments
Follow-up evaluations, including a thorough clinical examination and CT scan, were performed every 3 months for the rst year, every 6 months for 2 years, and annually thereafter. Diagnostic examinations were performed when recurrence was suspected. OS was calculated from the date of initiation of therapy to the time of death from any reason or terminal time of follow up, was the primary end point of assessment. Secondary assessment endpoints were PFS, which was de ned as the time between the onset of therapy and the progression or last time of follow up.

Statistical analysis
The statistical analyses were performed using a social science statistical software package, version 26.0 (SPSS Inc., Chicago, IL, US), and the best cut-off value of the NLR and PLR were determined using the receiver operating characteristic (ROC) curve. The categorical variables were analyzed with Fisher's exact or chi-squared tests. The survival curves were plotted by the Kaplan-Meier method and any differences were determined using a log-rank test. Predictors for survival were assessed by univariate and multivariate Cox regression analyses. Statistical signi cance was deemed to be a P-value < 0.05.

Patient and treatment characteristics
A total of 113 patients who met the inclusion criteria were chosen for our research study. The median age was 62 years (range: 47 to 80 years) and the majority of patients were male (n = 99, 87.6%). Primary tumors were located in the upper esophagus in 25 patients (22.1%), in the middle esophagus in 61 patients (54.0%), and in both regions in 27 patients (23.9%). A more detailed information of patient characteristics and beseline are shown in Table 1. 183.06. The NLR was closely associated with the extent of lymph node metastasis (P = 0.045) and the tumor stage (P = 0.043). A signi cant correlation was observed between PLR and the extent of lymph node metastasis (P = 0.002). Additionally, a high PLR and recurrence with distant organs metastasis were closely related (P = 0.014). The associations of NLR and PLR with the charactristics of clinical patholog are presented in Table 2. independently associated with poor OS or PFS, and advanced stage (III) were signi cantly correlated with decreased OS (Table 4).  Kaplan-Meier analysis con rmed that low PLR was associated with the added advantage of survival (P = 0.000, Fig. 3B).

Prognostic Effect Of Therapeutic Modalities By NLR and PLR
In the high NLR and PLR populations or the low PLR population, survival bene t was not different between surgery and dCRT (Fig. 4A, B, C). It is noteworthy that surgery was associated with a superior OS compared with dCRT in the low NLR population (P = 0.045). Figure 4D), whose clinicopathological parameters were no difference between surgery and dCRT (Table 5). However, there was no signi cant relationship between therapeutic modalities and PFS in the low NLR cohort of patients (P = 0.099).

Discussion
A systemic in ammatory response, that triggers the proliferation and metastasis of tumor cells through DNA damage and the facilitation of angiogenesis, substantially promotes the development of malignancies and affects survival of patients with cancer (15,23). Neutrophils are able to secrete cytokines and chemokines including interleukin-1, interleukin-6, tumor necrosis factor and myeloid growth factors, which promote tumor progression, inhibit the ability of immune cells to suppress immune functions and induce resistance to cytotoxic drugs (15,(24)(25). Additionally, platelets are a critical source of cytokines, such as transforming growth factor-β and vascular endothelial growth factor (VEGF), which assist angiogenesis and cell invasion. Moreover, lymphocytes can secrete several cytokines, including IFN-γ and TNF-α, to prevent tumor development from immune compartments and regulate the immunosurveillance process. The decreased lymphocyte count suggests inadequate host-to-tumor immunological reactions, with reduced responses against tumor (25)(26)(27). Taken together, these cells interact to form an in ammatory immune system, which have two main functions (anti-tumor and tumor promoting) under different conditions. Several previous studies have shown that systemic in ammation parameters, such as NLR, PLR and lymphocyte-to-monocyte ratio, are commonly supposed to identify the prognosis of various solid tumors (28)(29)(30)(31)(32). Therefore, NLR and PLR are proposed as easily determinable and cost effective in ammatory biomarkers that re ect the anti-tumor or tumor promoting function of the in ammatory immune system. In our retrospective study, we selected NLR and PLR to evaluate the prognosis in patients with ESCC in the middle and upper esophagus. In agreement with most previously published reports (32)(33), both pretreatment high NLR (> 2.07) and pretreatment high PLR (> 183.06) are strongly related to a worse PFS and OS compared with low indexes in these patients treated with surgery or dCRT.
Multivariate logistic regression analysis revealed that pretreatment NLR and PLR values were closely associated with survival. Moreover, both pretreatment high NLR and PLR were correlated with lymph node metastasis (N2/N3) of ESCC patients with tumors located in the middle or upper esophagus. However, stage III was only signi cantly associated with pretreatment high NLR but not pretreatment high PLR.
This negative result may be attributed to the small number of stage II cases examined. Additionally, we found the relationship that pretreatment high PLR patients had a high rate of recurrence with distant organs metastasis. This nding may be explained by the physiological mechanism of platelets. Platelets can protect circulating tumor cells from shear stresses as they circulate in the blood stream, induce VEGF and epithelial-mesenchymal transition, and promote tumor cell extravasation, adhesion and seeding of distant organ sites (34)(35)(36) (26,37). Second, lymphocytopenia can be induced by conventional radiotherapy (38).
The present research provides the rst clinical evidence that the pretreatment NLR value as a hematological biomarker can guide the treatment decision (surgery or dCRT). However, there are several limitations to this research. Our cohort involved a single center and was retrospective in nature, which may lead to bias. In addition, the sample size was relatively small. Finally, unknown other factors, including subsequent therapy, may potentially have affected the patient outcomes.

Conclusions
The pretreatment NLR and PLR, easy-to-use hematological markers, were independent prognostic indicators for patients with locally advanced ESCC located in the middle or upper esophagus that underwent radical surgery or dCRT. A low pretreatment NLR value made the decision to use radical surgery more certain as it produced a considerable therapeutic bene t. 2. We have ensured that we obtained every patient's consent for publication.
3. The patients' information involved in this article was classi ed.
4. The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request. The authors declare that they have no competing interests.