Using TILs to Predict Therapeutic Effect of Chemotherapy (Pertuzumab, Trastuzumab, Docetaxel) on HER2-positive Breast Cancer.

BACKGROUND/AIM: Recently, reports of the clinical implications of tumor-infiltrating lymphocytes (TILs) in breast cancer treatment have increased. We evaluated that chemotherapy with a TPD regimen (trastuzumab, pertuzumab, docetaxel) against HER2-positive breast cancer, using TILs as indicators.

PATIENTS AND METHODS: The subjects were 24 patients who had received TPD-chemotherapy. A semi-quantitative evaluation of lymphocytes invading the stroma in needle biopsy specimens prior to treatment as TILs was conducted, after which, sensitivity to chemotherapy and patient prognosis were evaluated.

RESULTS: Overall response rate was significantly higher in the high-TILs group than in the low-TILs group. Significant extension of the progression-free survival (PFS) and overall survival was found in the high-TILs group compared to the low-TILs group. In addition, high TILs numbers significantly contributed to the extension of PFS.

CONCLUSION: Monitoring antitumor immune response using TILs might be a useful indicator for predicting the curative effects of TPD chemotherapy for HER2-positive breast cancer.