The influence of timing of radiation therapy following breast-conserving surgery on 10-year disease-free survival

van Maaren, Marissa C.; Bretveld, Reini W.; Jobsen, Jan J.; Veenstra, Renske K.; Groothuis-Oudshoorn, Catharina G.M.; Struikmans, Hendrik; Maduro, John H.; Strobbe, Luc J.A.; Poortmans, Philip M.P.; Siesling, Sabine

doi:10.1038/BJC.2017.159

Title

The influence of timing of radiation therapy following breast-conserving surgery on 10-year disease-free survival

Author

van Maaren, Marissa C.

Bretveld, Reini W.

Jobsen, Jan J.

Veenstra, Renske K.

Groothuis-Oudshoorn, Catharina G.M.

Struikmans, Hendrik

Maduro, John H.

Strobbe, Luc J.A.

Poortmans, Philip M.P.

Siesling, Sabine

Abstract

Background: The Dutch guidelines advise to start radiation therapy (RT) within 5 weeks following breast-conserving surgery (BCS). However, much controversy exists regarding timing of RT. This study investigated its effect on 10-year disease-free survival (DFS) in a Dutch population-based cohort. Methods: All women diagnosed with primary invasive stage I-IIIA breast cancer in 2003 treated with BCS+RT were included. Two populations were studied. Population 1 excluded patients receiving chemotherapy before RT. Analyses were stratified for use of adjuvant systemic therapy (AST). Population 2 included patients treated with chemotherapy, and compared chemotherapy before (BCS-chemotherapy-RT) and after RT (BCS-RT-chemotherapy). DFS was estimated using multivariable Cox regression. Locoregional recurrence-free survival (LRRFS), distant metastasis-free survival (DMFS) and overall survival (OS) were secondary outcomes. Results: Population 1 (n = 2759) showed better DFS and DMFS for a time interval of >55 than a time interval of <42 days. Patients treated with AST showed higher DFS for >55 days (hazards ratio (HR) 0.60 (95% confidence interval (CI): 0.38-0.94)) and 42-55 days (HR 0.64 (95% CI: 0.45-0.91)) than <42 days. Results were similar for DMFS, while timing did not affect LRRFS and OS. For patients without AST, timing was not associated with DFS, DMFS and LLRFS, but 10-year OS was significantly lower for 42-55 and > 55 days compared to <42 days. In population 2 (n = 1120), timing did not affect survival in BCS-chemotherapy-RT. In BCS-RTchemotherapy, DMFS was higher for >55 than <42 days. Conclusions: Starting RT shortly after BCS seems not to be associated with a better long-term outcome. The common position that RT should start as soon as possible following surgery in order to increase treatment efficacy can be questioned.

Language

English

Source (journal)

The British journal of cancer. - London

Publication

London : 2017

ISSN

0007-0920

DOI

10.1038/BJC.2017.159

Volume/pages

117 :2 (2017) , p. 179-188