Annals of oncology : official journal of the European Society for Medical Oncology | 2019
Prognostic value of tumor-infiltrating lymphocytes in patients with early-stage triple-negative breast cancers (TNBC) who did not receive adjuvant chemotherapy.
Abstract
BACKGROUND\nAlthough stromal tumor-infiltrating lymphocytes (sTILs) have been considered an important prognostic factor in early-stage triple-negative breast cancer (TNBC), there have been limited data on their prognostic value in the absence of adjuvant chemotherapy.\n\n\nPATIENTS AND METHODS\nA pooled analysis was carried out using four cohorts of TNBC patients not treated with chemotherapy. sTILs were evaluated in the most representative tumoral block of surgical specimens. Cox proportional hazards regression models were used for invasive disease-free survival (iDFS), distant disease-free survival (D-DFS), and overall survival (OS), fitting sTILs as a continuous variable adjusted for clinicopathologic factors.\n\n\nRESULTS\nWe analyzed individual data of 476 patients from 4 centers diagnosed between 1989 and 2015. Their median age was 64\u2009years. The median tumor size was 1.6\u2009cm and 83% were node-negative. The median level of sTILs was 10% (Q1-Q3, 4%-30%). Higher grade was associated with higher sTILs (P\u2009<\u200910-3). During follow-up, 107 deaths, and 173 and 118 events for iDFS and D-DFS were observed, respectively. In the multivariable analysis, sTILs obtained an independent prognostic value for all end points (likelihood ratio χ2\u2009=\u20097.14 for iDFS; P\u2009<\u200910-2; χ2\u2009=\u20099.63 for D-DFS, P\u2009<\u200910-2; χ2\u2009=\u20095.96 for OS, P\u2009=\u20090.015). Each 10% increment in sTILs corresponded to a hazard ratio of 0.90 [95% confidence interval (CI) 0.82\u2009-\u20090.97] for iDFS, 0.86 (95% CI 0.77\u2009-\u20090.95) for D-DFS, and 0.88 (95% CI 0.79\u2009-\u20090.98) for OS, respectively. In patients with pathological stage I tumors with sTILs ≥30% (n\u2009=\u200974), 5-year iDFS was 91% (95% CI 84% to 96%), D-DFS was 97% (95% CI 93% to 100%), and OS was 98% (95% CI 95% to 100%).\n\n\nCONCLUSION\nsTILs add important prognostic information in systemically untreated early-stage TNBC patients. Notably, sTILs can identify a subset of stage I TNBC patients with an excellent prognosis without adjuvant chemotherapy.