Breast Cancer

SS 23 - Breast 3?- General

161 - Salvage Mastectomy Versus Second Conservative Treatment for Second Ipsilateral Breast Tumor Event: A Propensity-Score Matched Cohort Analysis

Tuesday, October 23
1:30 PM - 1:40 PM
Location: Room 303

Salvage Mastectomy Versus Second Conservative Treatment for Second Ipsilateral Breast Tumor Event: A Propensity-Score Matched Cohort Analysis
J. M. Hannoun Levi1, E. van Limbergen2, J. Gal3, R. Schiappa3, C. Polgár4, D. Kauer-Dorner5, D. Pasquier6, C. Lemanski7, S. Racadot Deloge8, G. Houvenaeghel9, B. Guix10, A. Belliere-Calandry11, K. Lössl12, B. Polat13, C. Gutierrez14,15, R. Galalae16, and V. Strnad17; 1Antoine Lacassagne Cancer Center, University of Cote d’Azur, Région de Nice, France, France, 2KU Leuven - University of Leuven, Department of Oncology, Experimental Radiation Oncology, B-3000 Leuven, Belgium, 3Antoine Lacassagne Cancer Center, University of Cote d’Azur, Nice, France, 4Centre of Radiotherapy, National Institute of Oncology, Budapest, Hungary, Budapest, Hungary, 5Radiation Oncology, Medical University of Vienna, Vienna, Austria, Vienna, Austria, 6Centre Oscar Lambret, Lille, France, 7Institut du Cancer de Montpellier, Montpellier, France, 8Radiation Oncology, Leon Berard Cancer Center, Lyon, France, Lyon, France, 9Surgical Oncology, Paoli-Calmettes Cancer Institute, Marseille, France, 10IMOR Foundation, Barcelona 08017, Spain, 11Radiation Oncology, Auvergne Jean Perrin Cancer Center, Clermont-Ferrand, France, 12Radiation Oncology, University Hospital Berne, Berne, Switzerland, 13Radiation Oncology, University of Wurzburg, Wurzburg, Germany, 14Radiation Oncology Department. Catalan Institute of Oncology, L'Hospitalet-Barcelona, Spain, 15University of Barcelona, L'Hospitalet-Barcelona, Spain, 16Medical Faculty, Christian-Albrechts-University, Kiel, Germany, 17Radiation Oncology, University Clinic Erlangen, Erlangen, Germany

Purpose/Objective(s): Second conservative treatment (2ndCT) has emerged as an option for patients with second ipsilateral breast tumor event (2ndILBTE) after conserving surgery and whole breast irradiation. We aimed to address the lack of evidence regarding the 2ndILBTE treatment by comparing oncological outcomes after 2ndCT or salvage mastectomy (SM standard care).

Materials/Methods: Oncological outcomes after 2ndILBTE treatment were analyzed using a propensity-score matched cohort analysis study by patients diagnosed with a 2ndILBTE occurring between 01/2000 and 12/2014. Patient data were collected from 15 hospitals/cancer centers in 7 European countries. Patients were offered management with 2ndCT (lumpectomy + brachytherapy) or SM. For comparative analyses, propensity scores were calculated with logistic regression and multiple imputations (for missing data). Matching (1:1) was achieved using the nearest neighbor method with a caliper of 0.1 (including data related to 2ndILBTE: age, 1st/2ndILBTE time interval, tumor size, histological type and grade, hormonal receptor and Her2 status, chemotherapy, hormonal therapy and 2ndILBTE period). The primary endpoint was disease-free survival (DFS) from the salvage treatment date. Secondary endpoints were overall survival (OS), metastatis-free survival (MSF) and 3rdILBTE free survival.

Results: Among the 1329 analyzed patients (SM: 942/2ndCT: 387), 430 were matched by propensity score (SM: 215/2ndCT: 215). The median follow-up was 65 months [95%CI 58-78] and 68 months [95%CI 57-75] for SM and 2ndCT respectively (p=0.28). In the matched analyses, no differences in 5-year DFS were noted between SM and 2ndCT (78% [95%CI 71-84] vs 82% [76–89]; p=0.22). Similarly, no differences were noted in 5-year OS (90% [86–95] vs 86% [81–92]; p=0.85), MSF (92% [87–96] vs 94% [90–98]; p=0.75) and 3rdILBTE (94% [90–98] vs 98% [95–1]; p=0.17).

Conclusion: To our knowledge, this is the largest matched-analysis between SM and 2ndCT for 2ndILBTE. Compared to SM, 2ndCT including re-lumpectomy and salvage brachytherapy does not seem to be associated with measurable differences of DFS, OS, MSF or 3rdILBTE. Consequently, 2ndCT could be considered as a viable option for salvage treatment.

Author Disclosure: J. Hannoun Levi: Consultant; BEBIG. E. van Limbergen: None. J. Gal: None. R. Schiappa: None. C. Polgár: None. D. Kauer-Dorner: None. S. Racadot Deloge: None. B. Guix: None. A. Belliere-Calandry: None. K. Lössl: None. B. Polat: None. C. Gutierrez: None. V. Strnad: Consultant; ELEKTA.

Jean Michel Hannoun Levi, MD, PhD

Disclosure:
Compensation
BEBIG: Consultant

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