Abstract 171P
Background
In early-stage triple-negative breast cancer (TNBC), stromal tumor-infiltrating lymphocytes (sTILs) are an independent prognostic factor. Further prognostic stratification may be possible by combining immune biomarkers including tertiary lymphoid structure (TLS) and PD-L1 expression in addition to TILs. Here, we evaluated the association of sTILs, PD-L1, and TLS with prognosis in TNBC not receiving chemotherapy.
Methods
We identified patients with stage I-III TNBC who did not receive adjuvant chemotherapy at the National Cancer Center Hospital between 2001 and 2015. sTILs and TLS were assessed according to guidelines and previous studies, respectively. PD-L1 expression in immune cells was evaluated by the VENTANA SP142 assay. Cox proportional hazards model was used to identify the prognostic value of sTILs, TLS, and PD-L1.
Results
A total of 125 patients were included. Among patients, the median age was 68 years (range 32-99), 69% were T1, and 85% were node-negative. Median sTILs were 10% (IQR 0-30), and 35 patients (28%) were sTILs ≥30%. PD-L1 was positive in 35 patients (28%). Sixty-three patients (50%) showed TLS: 36 patients (29%), ≥1% in the area adjacent to the tumor; 21 patients (17%), ≥10%; 6 patients (5%), ≥50%. In a multivariable analysis, sTILs ≥30% were significantly associated with better invasive disease-free survival (iDFS) (HR 0.19, 95%CI 0.06-0.61, p=0.005), and PD-L1 positivity was significantly associated with worse iDFS (HR 3.22, 95%CI 1.17-8.81, p=0.023). However, TLS was not significantly associated with iDFS. Patients with sTILs ≥30%/PD-L1 negative tumors had the most favorable prognosis (5y-iDFS 100%), and patients with sTILs <30%/PD-L1 positive tumors had the worst prognosis (5y-iDFS 28.6%, 95%CI 4.1-61.2). Patients with sTILs ≥30%/PD-L1 positive tumors (5y-iDFS 80.7%, 95%CI 56.3-92.3) and sTILs <30%/PD-L1 negative tumors (5y-iDFS 83.6%, 95%CI 72.9-90.4) were intermediate prognosis (p<0.001).
Conclusions
Combining sTILs and PD-L1 can stratify prognosis in TNBC patients who did not receive chemotherapy. Patients with sTILs ≥30%/PD-L1 negative tumor had excellent prognosis and may be safely omitted from chemotherapy.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
M. Yoshida: Financial Interests, Personal, Advisory Board: Chugai. T. Nishikawa: Financial Interests, Personal, Expert Testimony: Eisai; Financial Interests, Personal, Speaker’s Bureau: Eisai; Financial Interests, Personal, Speaker’s Bureau: AstraZeneca; Financial Interests, Personal, Speaker’s Bureau: Takeda. K. Yonemori: Financial Interests, Personal, Speaker’s Bureau: Pfizer; Financial Interests, Personal, Speaker’s Bureau: AstraZeneca; Financial Interests, Personal, Speaker’s Bureau: Eisai; Financial Interests, Personal, Advisory Board: AstraZeneca; Financial Interests, Personal, Advisory Board: Takeda; Financial Interests, Personal, Advisory Board: Chugai; Financial Interests, Personal, Advisory Board: Eisai; Financial Interests, Personal, Advisory Board: Ono; Financial Interests, Personal, Advisory Board: Novartis; Financial Interests, Personal, Advisory Board: Daiichi Sankyo. All other authors have declared no conflicts of interest.