Tumor-Infiltrating Lymphocytes and Breast Cancer Prognosis
In study results published in The Lancet Oncology, Carsten Denkert, MD, of the Institut fur Pathologie, Charité Universitätsmedizin Berlin, and colleagues reported that increased levels of tumor-infiltrating lymphocytes (TILs) in women receiving neoadjuvant chemotherapy may be associated with improved prognosis in those with HER2-positive and triple-negative breast cancers. However, increased levels of TILs was found to be an adverse prognostic factor for survival in patients with luminal HER2-negative breast cancer.
The study included 6 randomized trials from the German Breast Cancer Group; pretherapeutic core biopsies from 3,771 women who had primary breast cancer and were treated with neoadjuvant combination chemotherapy were evaluated. TILs were analyzed in 3 predefined groups: low (0% to 10% immune cells in stromal tissue within the tumor), intermediate (11% to 59%), and high (at least 60%).
Pathologic complete response rates were higher in the high-TIL groups than in the intermediate-TIL and low-TIL groups across several tumor subtypes. In addition, a 10% increase in TIL levels was associated with longer disease-free and overall survival in those with triple-negative disease, longer disease-free survival and nonsignificantly longer survival in those with HER2-positive disease, and shorter survival in those with luminal HER2-negative disease.
“Our data support the hypothesis that breast cancer is immunogenic and might be targetable by immune-modulating therapies,” Dr. Denkert and colleagues concluded. “In light of the results in luminal breast cancer, further research investigating the interaction of the immune system with different types of endocrine therapy is warranted.”