Abstract P2-08-08: Isolated ipsilateral local recurrence of breast cancer: Predictive factors and prognostic impact

Background Tumour features associated with isolated invasive breast cancer ipsilateral local recurrence (ILR) after breast conservative treatment (BCT) and consequences on overall survival (OS) are still debated. The aim of our study was to examine predictive factors of isolated ILR after BCT with in sano resection and whole breast irradiation as well as the impact of such an ILR on overall survival in a large multi-institutional cohort. Methods Patients were retrospectively identified from a large cohort of 23,375 consecutive patients who underwent BCT for invasive breast cancer in 16 cancer centres. End-points were ILR rate and OS. The impact of ILR on OS was assessed through multivariate analysis by logistic regression and Cox model, adjusted on ERs/Grade status (ERs+/Grade 1, ERs+/Grade 2, ERs+/Grade 3 and ERs-) and then on tumour subtypes. Results Of 15,570 patients, ILR rate was 3.1%. Cumulative ILR rates differed according to ERs/grade (ERs+/Grade2: HR=1.42, p=0.010; ERs+/Grade3: HR=1.41, p=0.067; ERs-: HR=2.14, p Conclusion ERs/Grade status, lack of endocrine therapy and tumour subtypes predict isolated ILR risk in patients treated with BCT. Short ILR-free-intervals represent a strong pejorative factor for OS. These results may help selecting initial treatment as well as tailoring ILR systemic chemotherapy. Citation Format: Houvenaeghel G, de Nonneville A, Cohen M, Classe J-M, Reyal F, Mazouni C, Chopin N, Martinez A, Darai E, Coutant C, Colombo P-E, Gimbergues P, Chauvet M-P, Azuar A-S, Rouzier R, Tunon de Lara C, Murraciole X, Agostini A, Goncalves A, Lambaudie E. Isolated ipsilateral local recurrence of breast cancer: Predictive factors and prognostic impact [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-08.