Long-term Outcomes with 3D Conformal External Beam Accelerated Partial Breast Irradiation (APBI)
Menée sur 293 patientes atteintes d'un cancer du sein traité entre 2006 et 2012 (durée médiane de suivi : 87 mois), cette étude évalue l'efficacité, du point de vue du taux de récidive ipsilatérale et du taux de survie sans progression à 7 ans, et les résultats esthétiques d'une irradiation partielle du sein par radiothérapie externe conformationnelle 3D accélérée
Résumé en anglais
Purpose : Long-term tumor control and cosmetic outcomes for accelerated partial breast radiation (APBI) delivered with 3D conformal external beam radiation (3D-CRT) remain limited. We seek to address these concerns by reporting our experience of 3D-CRT APBI with extended follow-up.
Methods : All patients treated with APBI delivered with 3D-CRT from January 2006 through December 2012 at a single institution were identified. Those with more than a year of follow-up were analyzed for ipsilateral breast tumor recurrence (IBTR), progression-free survival (PFS), cosmesis, and pain. Disease outcomes were analyzed by margin status (<2 mm, ≥2 mm), total radiation dose prescribed, presence of invasive disease, and American Society for Radiation Oncology (ASTRO) 2016 updated consensus groupings (suitable, cautionary, and unsuitable).
Results : 293 patients were identified, of which 266 had >1 year of follow-up. Median follow-up was 87 months (range: 13-156). Of the 266, 162 (60.9%) were ASTRO “suitable,” 87 (32.7%) were “cautionary,” and 17 (6.4%) were “unsuitable.” Seven-year rates of IBTR and PFS were 1.8% and 95.2%, respectively. Margin status, invasive versus in-situ disease, prescribed dose, and ASTRO grouping were not prognostic for either IBTR or PFS on univariate analysis. Cosmesis was good to excellent in 75.2%. Two patients (0.8%) had subsequent plastic surgery due to poor cosmesis. Narcotic medication for treatment site pain was needed by 6 (2.3%).
Conclusion : External beam APBI results in excellent long-term disease control. Good-to-excellent cosmetic outcomes are achieved in most patients, although increasing dose per fraction as well as greater percentage of irradiated breast were predictive of adverse post-treatment cosmetic outcomes. Select patients in “cautionary” and “unsuitable” consensus groupings do not appear to have inferior outcomes.
