Potential Prognostic Cellular Biomarker Investigated for Stage I Triple-Negative Breast Cancer

By: Julia Cipriano, MS
Posted: Friday, July 12, 2024

Chemotherapy-untreated patients with stage I triple-negative breast cancer and high stromal tumor–infiltrating lymphocyte levels had “excellent” 10-year breast cancer–specific survival outcomes, according to Marleen Kok, MD, PhD, of the Netherlands Cancer Institute, Amsterdam, and colleagues. Their findings, which were published in JAMA Oncology, further support the role of these cells as prognostic biomarkers in prospective clinical trials to optimize therapy for this population. The next step is to perform an international prospective study of whether chemotherapy can safely be omitted in patients who have stage I triple-negative breast cancer and high levels of tumor-infiltrating lymphocytes.

Using the Netherlands Cancer Registry, the investigators identified 4,511 patients with stage I triple-negative breast cancer diagnosed between 2005 and 2015; patients who had received neither neoadjuvant nor adjuvant chemotherapy were selected. Clinical data were matched with corresponding pathology data from the Dutch Pathology Registry. The investigators used the International Immuno-Oncology Biomarker Working Group guidelines to score the levels of stromal tumor–infiltrating lymphocytes for 1,041 patients. Follow-up data were provided for a median of 11.4 years.

The median level of stromal tumor–infiltrating lymphocytes was 5% (range, 1%–99%). A total of 74.4%, 25.6%, 19.5%, and 13.5% of the population demonstrated levels of below 30% and at least 30%, 50%, and 75%, respectively. According to the investigators, patients with pT1ab N0 vs pT1c N0 tumors had a more favorable outcome (10-year breast cancer–specific survival: 92% vs 86%). Stromal tumor–infiltrating lymphocyte levels of at least 30% were found to be associated with improved breast cancer–specific survival in the overall cohort (96% vs 87%; hazard ratio [HR] = 0.45).

Compared with patients who had pT1c tumors and stromal tumor–infiltrating lymphocyte levels of less than 50%, those with higher levels seemed to experience better outcomes (HR = 0.27). The latter population had a 10-year breast cancer–specific survival rate of 95%, which increased to 98% with stromal tumor–infiltrating lymphocyte levels of at least 75%; an association of lesser magnitude was found in those with pT1ab tumors.

Disclosure: For full disclosures of the study authors, visit jamanetwork.com.

JAMA Oncology

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