Predicting Neoadjuvant Chemoradiotherapy Response in Locally Advanced Rectal Cancer Using Tumor-Infiltrating Lymphocytes Density

J Inflamm Res. 2021 Nov 10:14:5891-5899. doi: 10.2147/JIR.S342214. eCollection 2021.

Abstract

Purpose: Accumulating evidence revealed the predictive value of tumor-infiltrating lymphocytes (TILs) for neoadjuvant chemoradiotherapy (nCRT) response in solid tumors. This study quantified TILs density using hematoxylin and eosin (H&E) stained whole-slide images (WSIs) and investigated the predictive value of TILs density on nCRT response in locally advanced rectal cancer (LARC) patients.

Patients and methods: Two hundred and ten patients diagnosed with LARC were enrolled in this study. The density of TILs in the stroma region was quantified by a semi-automatic method in WSIs. Patients were stratified into low-TILs and high-TILs groups using the median value as the threshold. The tumor regression grade (TRG) was used to assess the response to nCRT in tumor resected specimens. Based on TRG, patients were classified into major-responder (TRG 0-1) and non-responder (TRG 2-3) groups.

Results: The TILs density was significantly correlated with the nCRT response. Specifically, patients with high-TILs tend to have a higher major-responder rate than the low-TILs group (63.8% vs 47.6%, P = 0.026). Univariate analysis showed the TILs density was a predictor for the nCRT response (high vs low, odds ratio [OR] =1.94, 95% confidence interval 1.12-3.37, P = 0.019), and multivariate analysis further confirmed the correlation (adjusted odds ratio [AOR] = 2.41, 1.28-4.56, P = 0.007).

Conclusion: Patients with a high-TIL density have a higher major-responder rate than the low-TILs group, indicating patients with a strong immune response benefit more from nCRT. This semi-automatic method can facilitate the individualized preoperative prediction of the TRG for LARC patients before nCRT.

Keywords: digital pathology; locally advanced rectal cancer; neoadjuvant chemoradiotherapy response; tumor regression grade; tumor-infiltrating lymphocytes.

Grants and funding

This work was supported by the Key R&D Program of Guangdong Province, China [2021B0101420006], National Science Fund for Distinguished Young Scholars [81925023], National Natural Science Foundation of China [81771912, 82001986, and 82071892], High-level Hospital Construction Project [DFJH201805 and DFJH201914], the Applied Basic Research Projects of Yunnan Province, China, Outstanding Youth Foundation [202101AW070001], and Yunnan digitalization, Development and Application of Biotic Resource [202002AA100007].