Moderate versus ultra-hypofractionated locoregional breast radiotherapy: Results of a retrospective study during the covid-19 era.

Purpose: The use of ultra hypofractionated adjuvant breast radiotherapy for elderly patients was extended during the covid-19 pandemic. We compared its efficacy and safety versus moderate hypofractionation in elderly patients with breast cancer receiving locoregional radiotherapy at a single radiotherapy centre.

Methods: This retrospective analysis utilized routine patient data. Inclusion criteria comprised women aged 65 years or older with non-metastatic breast cancer, positive axillary nodes, and treated with locoregional radiotherapy following the ultra or moderate hypofractionation protocols. Outcomes studied included overall survival, disease-free survival, late normal tissue effects, and acute toxicity. Comparative analysis employed logistic regression and survival analysis with covariate adjustments.

Results: Two hundred and twenty-one patients were included, with a median age of 72.5 years (interquartile range [IQR]: 67.9-77.7 years) and a median follow-up of 36.3 months (IQR: 25.4-47.8 months). No significant differences were found in overall and disease-free survival rates between ultra and moderate hypofractionation protocols (adjusted hazard ratio [HR] for death: 0.81, 95 % confidence interval [CI]: 0.27-2.46, P=0.712; adjusted HR for relapse or death: 0.96, 95 % CI: 0.39-2.37, P=0.923). Although ultra-hypofractionation showed an increase in moderate late-onset breast oedema, no significant differences were observed regarding other more common moderate adverse events, such as acute dermatitis and late-onset homolateral arm oedema.

Conclusion: Our retrospective analysis suggests that the ultra-hypofractionation protocol for locoregional irradiation in elderly patients with breast cancer maintains an acceptable safety profile and shows no significant difference in efficacy compared to the moderate hypofractionation schedule. Prospective confirmation is awaited.