The presence of tumor-infiltrating lymphocytes ahead of treatment may help predict response to platinum-based chemotherapy in women with triple-negative breast cancer, according to a new study. The data are being presented at the American Society for Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois.

“Triple-negative breast cancers tend to be more aggressive compared to other types of breast cancers, and being able to predict response to therapy could greatly impact treatment decisions and patient outcomes,” said study author Shaveta Vinayak, MD, oncologist at University Hospitals (UH) Case Medical Center’s Seidman Cancer Center and Assistant Professor at Case Western Reserve University School of Medicine in Cleveland, Ohio. “Our research shows that the presence of lymphocytes before administering chemotherapy could predict a positive response to platinum-based therapy.”

Triple-negative breast cancers are those that do not have estrogen or progesterone receptors, and do not have an excess of the HER2 protein on the cancer cell surfaces. This makes it more difficult to treat because hormone-blocking or HER2-targeting treatments are not effective. Triple-negative breast cancers tend to occur more often in younger women and in African American women.

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Platinum-based therapies are being tested in clinical trials for triple-negative breast cancer, and evaluation of tumor-infiltrating lymphocytes is an important factor in determining response to this treatment. For oncologists, this could provide a new tool to individualize treatment for these women.

The study examined 70 patients with triple-negative breast cancer who had completed at least 4 of 6 planned rounds of chemotherapy. The density of lymphocytes from tissue and tumor sections from prechemotherapy biopsies was evaluated. Residual cancer burden index assessed pathologic response.

Response to platinum-based neoadjuvant chemotherapy was found to be predicted by tumor-infiltrating lymphocytes found in the connective tissue and the tumor itself. Tumor-infiltrating lymphocytes were significantly associated with subtypes of triple-negative breast cancer. The highest frequency of tumor-infiltrating lymphocytes occurred in the immunomodulatory subtype of triple-negative breast cancer.

Researchers from various institutions in the Eastern Cooperative Oncology Group, one of the largest clinical cancer research organizations in the United States that conducts clinical trials in all types of adult cancers, contributed to this analysis. Funding for this study was provided by Breast Cancer Research Foundation, ASCO Conquer Cancer Foundation, Triple-Negative Breast Cancer Foundation, Myriad Genetics, and National Institutes of Health (Stanford CTSA).