Evaluation and comparison of intratumoural and intrastromal infiltrating lymphocytes with clinicopathological features in breast carcinoma patients who have received neoadjuvant chemotherapy - A cross-sectional study

BACKGROUND: The microenvironment of breast cancer plays a significant role in determining the prognosis of the disease. With the shifting paradigm on the predictive factors post-Neoadjuvant Chemotherapy (NAC), it was sought out that Tumour infiltrating lymphocytes (TILs) are of valuable use for the same. Yet, the delineation of the two types - Intrastromal and Intratumoural has seldom been facilitated. This study, therefore, aimed to evaluate, analyse and compare the two - to gauge the importance of the treatment outcome and clinicopathological features. MATERIALS AND METHODS: 180 breast cancer patients were included in this study who underwent NAC, and their post-surgically resected tumour specimens were sectioned and stained using routine Haematoxylin and Eosin techniques. The evaluation of TILs in the stroma and tumour was done based on the standardised guidelines. RESULTS: Out of the 180 patients, 55 (i.e. 30.56%) displayed pathological complete resolution (pCR). Furthermore, Intratumoural TILs had a slight association with the pCR (p = 0.0335) whereas Intrastromal TILs had a significantly large association with pCR (p < 0.0001) dependent on the lymphocytic response. Backward regression revealed that - the age at operation, pCR, lymph node involvement and menopause highly contributed to predicting 68.2% of the total cases correctly with a sensitivity of 93.0% and specificity of 24.6% for Intratumoral TILs. Age at operation, pCR, lymph node involvement and tumour emboli highly contributed to predicting 71.5% of the total cases correctly with sensitivity of 71.6% and specificity of 71.4% for Intrastromal TILs. CONCLUSION: TILs and the prediction of NAC and pCR should be made standardised and reproducible so that they can be universally available to all patients with breast cancer. Through this study, further avenues of research have opened up for their relations with clinicopathological features mainly age at operation and menopausal status.