Breast cancer lesions containing high levels of tumor-infiltrating lymphocytes appear to give patients a better prognosis and better outcomes when compared with patients whose tumors have fewer levels of the white blood cells, researchers said here.
For every 10 percent increase in stromal tumor-infiltrating lymphocytes found in the breast cancer tissue, there is a corresponding 16% increase in the chance that a woman will achieve a pathological complete response to therapy (P=0.038), said Sherene Loi, MD, PhD, head of the Translational Breast Cancer Genomics Lab at the Peter MacCallum Cancer Centre in Melbourne, Australia.
"Our new data further support the positive relationship between tumor-infiltrating lymphocytes and better outcomes with trastuzumab therapy, this time in a cohort of patients with newly diagnosed HER2-positive breast cancer who received the therapy before surgery," Loi said in a press briefing at the 36th annual San Antonio Breast Cancer Symposium.
"It seems that levels of tumor-infiltrating lymphocytes may be a good biomarker of response to trastuzumab in primary breast cancer, something that researchers have been looking for with little success for some time," added Loi.
Loi and colleagues scrutinized breast cancer tissues from 445 women, identifying through standard pathology 156 women whose breast cancers had high levels of tumor-infiltrating lymphocytes. She reported that 47.4 percent of the women with high levels of the infiltrating lymphocytes achieved a pathological complete response, compared with 31.7 percent of the women in the entire cohort.