Five-year results of the Very Accelerated Partial Breast Irradiation VAPBI phase I-II GEC-ESTRO trial 

ESTRO 2024 Congress Report

We present the five-year results of a phase I-II trial that was promoted by the Groupe Européen de Curiethérapie (GEC)-ESTRO breast working group and carried out in three European hospitals between 2017 and 2019.

The key finding of this study is the confirmation that accelerated partial breast irradiation (APBI) can be used safely in selected low-risk cases in a short period of only two days, which we call very accelerated partial breast irradiation (VAPBI). Standard postoperative partial breast treatment for early breast carcinomas with multi-catheter interstitial brachytherapy (MIBT) requires the application of seven to eight fractions over four to five days, as used in the phase III APBI GEC-ESTRO trial.

The methodology to demonstrate this was a prospective multicentre study, which began with the treatment of 33 women who each received four fractions of 6.25Gy in two to three days. Then, as no acute complications were reported, 48 more patients were treated with only three fractions of 7.45Gy in two days. In total, of these 81 women, 71 were treated in two days. The mean age was 68 years with a range between 51 and 90 years. The median follow-up was 58 months. Two breast-cancer recurrences were recorded at 37 and 60 months. The five-year locoregional control rate was estimated at 95.9%. The acute side effects were minimal; late fibrosis or slight (G1) induration in the surgical bed was reported in 22% of the women and moderate (G2) induration in 8.6%. There was no case of telangiectasia. The cosmetic outcome was good or excellent in 95% of the women. These results are similar to those found in the phase III trial and confirm that VAPBI can be a good alternative to APBI in appropriate cases.

There are significant implications of this research for future cancer treatments. APBI can be completed in just two days with MIBT, which means the patient is kept for only a single night with plastic tubes, instead of the current standard five days with the application of external beam radiation (EBRT). This approach, VAPBI with MIBT, can be selected for women with left-sided tumours to reduce the dose to the heart and lungs compared with EBRT, or for women who live far away from the treatment centre. Another advantage is the reduction of the workload on the Clinics. VAPBI is a good alternative treatment to discuss with the patient.

On behalf of the GEC-ESTRO breast working group

E-mail: jguinot@fivo.org

José Luis Guinot

Department of Radiation Oncology, Foundation Instituto Valenciano de Oncologia (IVO), Valencia, Spain

Cristina Gutiérrez-Miguelez

Department of Radiation Oncology, Catalan Institute of Oncology, Barcelona, Spain

Norbert Mészáros

Department of Radiation Oncology, National Institute of Oncology, Budapest, Hungary