Tumor-Infiltrating Lymphocytes (TILs) and Risk of a Second Breast Event After a Ductal Carcinoma in situ

• Published in: Frontiers in oncology Vol. 10; p. 1486
• Main Authors: Farolfi, Alberto, Petracci, Elisabetta, Serra, Luigi, Ravaioli, Alessandra, Bravaccini, Sara, Ravaioli, Sara, Tumedei, Maria Maddalena, Ulivi, Paola, Canale, Matteo, Puccetti, Maurizio, Falcini, Fabio, Folli, Secondo, Curcio, Annalisa, Rocca, Andrea
• Format: Journal Article
• Language: English
• Published: Frontiers Media S.A 19.08.2020
• Subjects: breast conserving surgery; ductal carcinoma in situ; Oncology; radiotherapy; second breast event; tumor infiltrating lymphocytes; tumor recurrence
• ISSN: 2234-943X; 2234-943X
• DOI: 10.3389/fonc.2020.01486

Women with a diagnosis of ductal carcinoma in situ (DCIS) have a high risk of developing a second breast event (SBE). The immune system might play a role in trying to prevent a SBE. Patients diagnosed with DCIS were identified in the population-based cancer registry of Area Vasta Romagna from 1997 to 2010. Median follow-up is 8.5 years. Tumor-infiltrating lymphocytes (TILs) were evaluated both in index DCIS and in SBE. The main endpoint was to assess the association between TILs' levels in index DCIS and risk of a SBE. Out of 496 DCIS patients, 100 SBEs (20.2%) were identified: 55 ipsilateral (11.1%) and 43 contralateral (8.7%). The distribution of TILs was heterogeneous, but significantly associated with grade, necrosis, screen detection and type of surgery. Patients stratified according to TILs percentage (≤5% and >5%) did not show a statistically significant difference in the 5-year cumulative incidence of SBEs: 14.9% (95% CI 11.3–19.1) and 11.0% (95% CI, 6.9–16.2), respectively ( p = 0.147). In the subgroup of patients who did not receive radiotherapy, TILs >5% were associated with a reduced risk of SBE (HR 0.34, 95% CI 0.14–0.82, p = 0.016). Although we did not find any significant association between TILs and SBE, further studies evaluating their role according to radiotherapy are warranted.