Can NLR/PLR/CEA be a marker for predicting a complete pathological response in locally advanced rectal cancer?

Aim: The standard treatment for locally advanced (T3-4 and/or N +) rectal cancer (LARC) is Total Mesorectal Excision (TME) and adjuvant chemotherapy after neoadjuvant chemo-radiotherapy (n-CRT). Various clinical or pathological complete response (pCR) rates after neoadjuvant therapy have been reported in the literature. Neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) or carcinoembryonic antigen (CEA) levels are used as prognostic markers for many tumors.The aim of this study is to investigate the relationship between treatment response and the above markers in patients receiving n-CRT for LARC. Material and Methos: The pathology results of 113 patients who underwent TME after n-CRT were divided into 4 groups according to the modified ryan tumor regression grade (TRG) classification. Among these groups, NLR, PLR and CEA levels, which are considered prognostic markers in response evaluation, were compared with their changes before and after neoadjuvant treatment. Results: While 11 (9,7%) patients had pCR (TRG 0), 41 (36,3%) patients had good response (TRG 0 and 1), 72 (63,7%) patients had a poor response (TRG 2 and 3) to n-CRT. While the initial prognostic markers were similar between the groups, post-n-CRT values were found to be significantly lower in the group with good response. Discussion: It is not possible to predict n-CRT response in LARC patients at the time of diagnosis, but NLR, PLR or CEA values and changes in these values may be useful in predicting treatment response.