Significance of tumor-infiltrating lymphocytes in tumor regression in breast cancer: A study in a tertiary care cancer center in South India

Abstract

ABSTRACT Background: Tumor immunology plays a significant role in predicting tumor biology and how a tumor is going to respond to neoadjuvant chemotherapy (NACT). Tumor-infiltrating lymphocytes (TILs) are the easiest and by far the cheapest method of assessing tumor immunity. Many studies have suggested that TILs play an important role in tumor regression in breast cancer. Aim: The aim of the current study was to determine significance of TILs in tumor regression in breast cancer. Materials and Methods: Patients with newly diagnosed and histologically proven breast cancer who were treated with both NACT and surgery in our institute were included in the study. TILs were assessed both before and after NACT, and were correlated with the relative amount of tumor regression and molecular subtypes based on the immunohistochemistry profile. Results: The study included 43 specimens of carcinoma breast in females. 42 cases were diagnosed with invasive carcinoma, no special type (NST), and one with lobular carcinoma. Pathological complete remission (pCR) was noted in 6 cases, partial remission (PRe) in 12 cases, and no response in 25 cases. TILs were noted before and after NACT in all cases and were correlated with other clinicopathological parameters. Conclusion: The present study highlights that TILs play a vital role in tumor regression and can be included in routine reporting. It can provide an insight into tumor biology.