Abstract P1-10-04: Impact of body mass index (BMI) on the predictive and prognostic value of stromal tumor-infiltrating lymphocytes (sTIL) in triple-negative breast cancer (TNBC) patients treated with neoadjuvant chemotherapy (NACT)

Background. High levels of sTIL have been associated with an increased pCR rate after NACT. Recent experimental and human data have demonstrated that obesity is associated with T-cell dysfunction (mediated by increased expression of checkpoints PD-1, LAG3 and TIM3), herewith reducing antitumor immune response. Here, we evaluated the value of sTIL in predicting pCR and prognosis in TNBC treated with NACT according to patient’s BMI. Patients and methods. We considered two institutional retrospective series of 452 TNBC patients treated with NACT (Leuven: n= 174, and, Curie: n= 278). Underweight patients ( Results. 236 (53%), 132 (30%) and 77 (17%) patients were lean, overweight and obese, respectively. pCR was achieved in 181/445 (41%) of the patients. Median sTIL was 11% and 99/445 (22%) tumors had high sTIL. Median follow-up time was 7.63 years. BMI was associated with menopausal status (33.8% lean and 50.4% overweight u0026 obese patients were postmenopausal, p Conclusion. In this study, we demonstrated that in TNBC patients treated with NACT, high sTIL predict pCR and favorable prognosis only in lean patients. Citation Format: Christine Desmedt, Francois Richard, Lynn Jongen, Anne-Sophie Hamy-Petit, Hans Wildiers, Jan Ardui, Kevin Punie, Ann Smeets, Patrick Berteloot, Ignace Vergote, Maricl Lae, Diane Decroze, Didier Meseure, Fabien Reyal, Elia Biganzoli, Patrick Neven, Giuseppe Floris. Impact of body mass index (BMI) on the predictive and prognostic value of stromal tumor-infiltrating lymphocytes (sTIL) in triple-negative breast cancer (TNBC) patients treated with neoadjuvant chemotherapy (NACT) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-10-04.