Abstract

There are controversies about the relation between the peripheral lymphocyte levels and response to neoadjuvant therapy. While some authors have reported that a positive correlation between peripheral lymphocyte levels and tumor response, others have suggested the opposite. In the present study, we aimed to investigate the possible relations between the changes in circulating lymphocyte counts due to neoadjuvant chemoradiotherapy (CRT) and intratumoral lymphocytic response (ILR) and tumor regression grade (TRG) in locally advanced rectal cancers. Lymphocyte levels before, during and after CRT as well as before surgery and pathologic findings including ILRs and TRGs were recorded. Lymphocyte levels before CRT were accepted as absolute values. After the changes in the lymphocyte levels during and after CRT and before the surgery were recorded as ratios to the absolute values, the relation between the changes in lymphocyte levels, ILR and TRG were studied by using Pearson and Spearman correlation tests. There was a positive correlation between changes in peripheral lymphocytic levels after neoadjuvant CRT and ILRs. However, there were no other correlations between changes in lymphocytic levels and TRGs and ILRs. The changes in the peripheral lymphocyte counts after CRT may be predictive for ILR. Further studies may provide more information about the relation between peripheral lymphocytes and TILs and tumor response to neoadjuvant CRT.

Key words: Rectal neoplasms, neoadjuvant therapy, lymphocyte count, intratumoral lymphocytic response, tumor regression grade