In a Dutch retrospective study reported in the Journal of Clinical Oncology, de Jong et al found that higher levels of stromal tumor-infiltrating lymphocytes (sTILs) were associated with “excellent prognosis” in young women with node-negative triple-negative breast cancer who did not receive (neo)adjuvant systemic therapy.
The study involved data from a Dutch population-based registry on women diagnosed with N0 triple-negative breast cancer at younger than age 40 between 1989 and 2000 who had received no (neo)adjuvant systemic therapy. A total of 441 had sTIL measurements available through evaluation of formalin-fixed paraffin-embedded blocks retrieved from the Dutch Pathology Registry. Percent sTILs was determined as the area occupied by mononuclear inflammatory cells over the total intratumoral stromal area. Patients were categorized according to sTIL percentages of < 30%, 30% to < 75%, and ≥ 75%.
sTIL percentages were > 30% in 230 (52.2%) of the 441 women, 30% to < 75% in 117 (26.5%), and ≥ 75% in 94 (21.3%).
Rates of distant metastasis or death at 15 years were 2.1% (95% confidence interval [CI] = 0%–5.0%) for sTIL percentage ≥ 75%, 15.7% (95% CI = 9.0%–22.3%) for 30% to < 75%, and 38.4% (95% CI = 32.1%–44.6%) for < 30% among all patients. Rates were 3.4%, 17.5%, and 32.6%, respectively, among 59, 57, and 136 patients with T1a/b/c tumors, and 0%, 14.0%, and 47.0%, respectively, among 35, 58, and 92 patients with T2/3 tumors.
Rates of overall survival at 15 years were 93.6% (95% CI = 88.8%–98.7%) for sTIL percentage ≥ 75%, 75.5% (95% CI = 68.1%–83.8%) for 30% to < 75%, and 60.2% (95% CI = 54.2%–67.0%) for < 30% among all patients. Rates were 93.2%, 71.8%, and 65.8%, respectively, among patients with T1a/b/c tumors, and 94.3%, 79.3%, and 52.1%, respectively, among patients with T2/3 tumors.
In multivariate analysis, each 10% increase in sTILs was associated with a significant reduction in risk of death (adjusted hazard ratio = 0.81, 95% CI = 0.76–0.87, P < .001).
The investigators concluded, “Chemotherapy-naive, young patients with N0 triple-negative breast cancer with high sTILs (≥ 75%) have an excellent long-term prognosis. Therefore, sTILs should be considered for prospective clinical trials investigating (neo)adjuvant chemotherapy de-escalation strategies.”
Sabine C. Linn, MD, of the Department of Molecular Pathology, Netherlands Cancer Institute, Amsterdam, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by The Netherlands Organization for Health Research and Development, A Sister’s Hope, Dutch Cancer Society, Agilent Technologies Inc, and others. For full disclosures of the study authors, visit ascopubs.org.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.