A comparison of three different radiotherapy boost techniques after breast conserving therapy for breast cancer

Abstract

Purpose: Compare different boost techniques after breast conserving therapy (BCT) in terms of local and loco-regional recurrences.

Materials and methods: From 2000 to 2005, patients treated with BCT for invasive breast cancer (BC) were included. An electron boost (EB) was performed for a superficial boost-volume (less than 29 mm under the epidermis), in all other cases a brachytherapy boost (BTB) was proposed. When patients refused a BTB or it was not possible for technical reasons, a photon boost (PB) was given. The primary endpoints were local and loco-regional recurrences. Secondary endpoints were metastasis-free and overall survival.

Results: 1379 patients were eligible for analysis. Most patients (1052) received an EB, 225 a BTB and 76 a PB. At a median follow-up of 8.8 years, 35 (2.5%) patients developed a local or loco-regional recurrence. Ten years local relapse-free rate was 97.9%. No differences between boost techniques were observed in relapse risk, metastasis-free and overall survival after multivariate analyses.

Conclusion: In women treated with BCT followed by a boost irradiation to the tumor bed, no difference in local and loco-regional recurrence, metastasis-free and overall survival was observed comparing three different boost techniques. Outcome was excellent regardless of the boost technique.

Keywords: Boost technique; Breast cancer; Breast conserving therapy; Radiotherapy.