Tumor lymphocyte immune response to preoperative radiotherapy in locally advanced rectal cancer: The LYMPHOREC study

ABSTRACTIntroduction: Some studies have suggested that baseline tumor-infiltrating-lymphocytes (TILs), such as CD8+ and FoxP3+ T-cells, may be associated with a better prognosis in colorectal cancer. We sought to investigate modulation of the immune response by preoperative radiotherapy (preopRT) and its impact on survival in locally advanced rectal cancer (LARC).Materials & Methods: We analyzed data for 237 patients with LARC who received RT. Density of TILS (CD8+ and FoxP3+) in intraepithelial (iTILs) and stromal compartments (sTILs) were evaluated from surgery pathological specimens and biopsies performed at baseline. The primary endpoint was to assess the impact of infiltration of the tumor or tumor site after preopRT on progression-free survival (PFS) and overall survival (OS). Secondary endpoints were the impact of dose fractionation scheme on TILs.Results: In univariate analysis, several factors significantly correlated (p<0.05) with PFS and/or OS (T-stage, M-stage, the delay between RT and surgery...