Body mass index and tumor infiltrating lymphocytes in triple-negative breast cancer
Menée à partir d'échantillons tumoraux prélevés sur 445 patientes atteintes d'un cancer du sein triple négatif traité par chimiothérapie néoadjuvante, cette étude évalue, en fonction de l'indice de masse corporelle, l'association entre la quantité de lymphocytes ayant infiltré la tumeur et la réponse pathologique complète, la survie sans événement et la survie globale
Background : High levels of stromal tumor infiltrating lymphocytes (sTIL) are associated with increased pathological complete response (pCR) rate and longer survival after neoadjuvant chemotherapy in triple-negative breast cancer (TNBC) patients. Here, we evaluated the value of sTIL in predicting pCR and explored prognosis in TNBC patients treated with neoadjuvant chemotherapy according to body mass index (BMI).
Methods : sTIL were scored centrally on pre-treatment biopsies from two retrospective series of non-underweight TNBC patients (n = 445). sTIL and BMI were considered as binary (sTIL: <30.0% versus ≥30.0%, BMI: lean versus overweight and obese) and continuous variables. Associations with pCR (ypT0/isN0) were assessed using logistic regression, and associations with event-free (EFS) and overall survival (OS) using Cox regressions.
Results : 236 (53.0%) patients were lean and 209 (47.0%) overweight and obese. pCR was achieved in 181/445 (41.7%) patients. Median sTIL was 11.0% and 99/445 (22.2%) tumors had high sTIL. A statistically significant interaction between sTIL and BMI, considered as categorical or continuous variables, for predicting pCR was observed in the multivariable analysis (p=.03 and .04, respectively). High sTIL were statistically significantly associated with pCR in lean (odds ratio, OR = 4.24, 95%CI = 2.10-8.56, p<.001), but not in heavier patients (OR = 1.48, 95%CI = 0.75-2.91, p=.26) in the multivariable analysis. High sTIL were further associated with increased EFS in lean (hazard ratio, HR = 0.22, 95%CI = 0.08-0.62, p=.004), but not in heavier patients (HR = 0.53, 95%CI = 0.26-1.08, p=.08). Similar results were obtained for OS.
Conclusion : BMI is modifying the effect of sTIL on pCR and prognosis in TNBC patients treated with neoadjuvant chemotherapy.
Journal of the National Cancer Institute , résumé, 2019