“WALKING INTO THE FUTURE”
16-17 November 2023, Prague, Czech Republic
Report on breast
During the GEC-ESTRO worshop 2023, different lectures about breast brachytherapy took place by experts in the breast group.
At the beginning of the workshop, a breast presentation focused on the role of brachytherapy in breast cancer took place on the afternoon of Thursday, November 16, by Jean-Michel Hannoun-Levi. A magnificent presentation of the updated results of the clinical trials of Accelerated Partial Breast Irradiation (APBI) were presented, with the different techniques explored and an update of very-acelerated schedules were presented. He also review the different techniques from the beginning of the use of APBI to the new very-acelerated schedules
During the second day of workshop, The Breast Lectures took part during the second day of the workshop, and they were presented by Jean-Michel Hannoun-Levi from Antoine Lacassagne Cancer Center, University Côte d'Azur (France) with the topic of “Brachytherapy: Making the difference”.
Firstly, Drs. Vratislav Strnad from Universitatsklinikum Erlangen (Germany) and Csaba Polgar from National Institute of Oncology in Budapest (Hungary) presented the 10-year results of the phase III non-inferiority study of GEC-ESTRO. A total of 16 European hospitals participated in this study, recruiting 1184 patients. (1) Participants had the following characteristics: age greater than or equal to 40 years, pTis or pT1-T2 (<3cm), pN0/pNmi and M0, with clear margins after surgery of at least 2mm, without lymphovascular involvement or extensive intraductal component. Patients were randomized to receive either whole-breast irradiation of 50 Gy with a boost of 10 Gy or APBI using multicatheter brachytherapy. Of the 1184, 633 patients were randomized to receive APBI using multicatheter brachytherapy. The 10-year results are comparable in patients treated with breast conserving surgery followed by APBI using multicatheter brachytherapy in "suitable" and "cautionary" risk groups, according to ASTRO criteria. In the “suitable” and “cautionary” groups, the cumulative incidence (95% CI) of local recurrence at was 3.29% (1.44-5.13%) and 5.03% (1.8-8.27%), respectively (p = 0.612). 10-year disease-free survival was 81.91% (78.1-85.9%) and 83.63% (78.31-89.32%), respectively (p = 0.63). 10-year overall survival was 88.26% (85.07-91.57%) and 95.04% (91.92-98.27%), respectively (p = 0.02). (2)
Consequently, the authors believe that in due time, a careful retrial of current ASTRO selection criteria for APBI should be considered.
Based on the results, the authors exposed a subanalysis from some traditional intermediate risk GEC-ESTRO group without any differences on the clinical outcomes Due to these results, the authors propose to update the patient selection for APBI. In the low-risk group, they consider including patients between 40-50 years old, single-center DCIS with free margins, invasive lobular carcinoma and positive HER2; in the intermediate-risk group, the inclusion of patients with pN1mi, LVI and triple-negative breast cancer (TNBC) can be unclear.
Dr. Jose Luis Guinot, from Instituto Valenciano de Oncología (IVO) (Spain), gave the second lecture, who presented the 5-y oncologic outcomes from multicenter very accelerated partial breast irradiation (VAPBI) with multicatheter interstitial brachytherapy.
This is a prospective, nonrandomized, multicenter Phase II trial endorsed by the GEC-ESTRO Breast Working Group. Patients received high-dose-rate brachytherapy, four fractions of 6.25 Gy in 2-3 days (n=33), and three fractions of 7.45 Gy in 2 days (n=48), and 16Gy in one fraction. This schemes were compared with the standard APBI treatment, eight fractions of 4Gy or 7 fractions of 4.3 Gy in 4-5 days. (3)
With a median follow-up of 58 months, the locorregional control rate was 95.9%, the overall survival was 92.5% and the cause-specific survival was 98.7%. Regarding toxicity G2 fibrosis increased from 2.5% to 8.6%, with progressive fibrosis in 6% of cases.
He also showed the single fraction in elderly breast irradiation in patients >65 years results. The toxicity outcomes were hiperpigmentation (G1: 26.7%) and late fibrosis (G1: 27%), with an excellent cosmesis 76.4%. No relapses in a follow-up of 40m.
In that way, the results showed no differences on oncological outcomes between the three schedules proposed, and acceptable toxicity. However, further follow-up is mandatory.
To summarize, the mature data provided confirm the value of Breast Brachytherapy for APBI patients based on GEC-ESTRO phase III trial (1). Furthermore, the recent evidence from the new shedules produce similar early-term oncological outcomes and toxicity, and they supported the logistic convenience four our patients logistics. The studies are very promising and lead us to think about shortening the treatment duration of these patients in the future, improving the data on oncological outcomes, reducing toxicity and improving the efficiency of our treatments with respect to fractionation without interfering with local control or overall survival.
Adriana Martínez-lage Goñi
Resident of Radiation Oncology,
Clínica Universidad de Navarra, Pamplona, Navarra, Spain