Pre-treatment neutrophil to lymphocyte ratio as a predictive marker for pathological response to preoperative intensity-modulated chemoradiotherapy in pancreatic head cancer

Introduction: The pre-treatment neutrophil to lymphocyte ratio (NLR) was reported to be a predictive indicator of pathological response of pancreatic cancer to neoadjuvant chemoradiotherapy (NAC-RT). The reported cut-off value of NLR is 2.2. Intensity modulated radiotherapy (IMRT) has shown to be able to improve pathological response by escalating radiological dose intensity. The aim of this study is to clarify the association between pre-treatment NLR and the pathological response to NAC-IMRT in pancreatic cancer patients. Methods: The consecutive 17 borderline resectable pancreatic cancer patients who underwent pancreatico-duodenectomy after NAC-IMRT between December 2017 and December 2019 were studied. Predictive factors, including NLR, platelet to lymphocyte ratio (PLR), and prognostic nutrition index (PNI), and CRP/albumin ratio (CAR) were measured prior to treatment. A comparison was made between those with a good response (Evans classification IIb/III) and those with a poor response (Evans I/IIa). Result: The 17 patients comprised 7males and 10 females, and the median age was 66 (range,57-86). The mean NLR value was significantly higher in the poor response group than in the good response group (3.39 vs 1.92; p=0.02), whereas the other examined factors demonstrated no significant differences between the two groups.From the ROC curve, the optimal cut-off level of the pretreatment NLR for predicting pathological non-responders (Evans I/IIa) was determined to be 3.06 (AUC=0.929). Conclusion: NLR was a best predictive indicator among various nutritional indexes. The cut-off level of the pretreatment NLR between might be different between NAC-IMRT and NAC-RT because of the difference of effective radiation dose.