Correlation between Tumor-Infiltrating Lymphocytes and Pathological Response in Locally Advanced Breast Cancer Patients Who Received Neoadjuvant Chemotherapy in H. Adam Malik General Hospital.

BACKGROUND: Tumor-infiltrating lymphocytes (TILs) are emerging as biomarkers mediating tumor response to treatments. Earlier studies have provided evidence that the level of TILs has prognostic value, particularly in triple-negative and human epidermal growth factor receptor-2-positive breast cancer. Moreover, the level of TILs has been associated with treatment outcome in patients undergoing neoadjuvant chemotherapy, and there is a strong correlation with pathologically complete response. In this study, we analyzed whether changes in TILs take place after neoadjuvant therapy and if they correlate with pathological response to treatment.

PATIENTS AND METHODS: We retrospectively analyzed the specimen slides from the Department of Anatomic Pathology of H. Adam Malik General Hospital during 2011-2015. We identified 51 patients fulfilling the inclusion criteria of this study. The histological sections had already been evaluated by hematoxylin and eosin slides. They were reassessed by our pathologist for the percentage of intratumoral and stromal TILs. The correlation with pathological response of the tumor after neoadjuvant therapy was also studied in these patients. Each case was also defined as high- or low-TIL breast cancer adopting previously validated cutoffs.

RESULTS: The mean age of the 51 patients was 49.22 years. The most frequent type of breast cancer histology was invasive ductal breast carcinoma in 49 (96%) patients, and there were 2 (4%) patients with lobular carcinoma. The histopathological grading for high TILs was grade 1 in 5 patients, grade 2 in 15 patients, and grade 3 in 3 patients. High TILs that had a pathologically complete response were found in 47.8% of patients, and low TILs were found in 28.8%. There was no significant correlation between TILs and pathological response in patients with neoadjuvant chemotherapy (p = 0.157).

CONCLUSIONS: This research has not been able to demonstrate a significant correlation between TILs and pathological response in patients with locally advanced breast cancer who received neoadjuvant chemotherapy, but high TILs were more likely to have a complete response. Further information may prove useful for future biomarker trials.