28P - One-week ultra-hypofractionated partial breast RT in early breast cancer: 3DCRT vs IMRT

Background

The purpose of the study was to evaluate the toxicity, local control, overall and disease-free survival of elderly breast cancer (BC) patients treated with adjuvant once-weekly ultra-hypo fractionated radiotherapy (RT) either with intensity-modulated RT (IMRT) or 3D conformal RT (3DCRT).

Methods

From 2019 to 2022, patients with BC receiving RT in dose 5.2 Gy in one week to the partial breast after breast-conserving surgery were considered for the study. Inclusion criteria were: T1–T2 invasive BC, no axillary involvement, age ≥ 60 years.

Results

A total of 154 patients were included in the study. Median age was 71 (61–86) years. Most of BC were T1 (24.7%), while the remaining were T2 (75.3%). The only severe acute toxicity (G3) at the end of RT was erythema (1.3%), registered in the 3DCRT group. With 24 months of median follow-up, severe early–late toxicity (G3) was reported in terms of fibrosis and breast retraction, both with an incidence of 3.24%, mostly in the 3DCRT group. Oncological outcomes at a median follow-up of 2.4 years reported 141/154 (91.5%) patients alive and free from any event and 6 (3.9%) isolated locoregional recurrences. At 3 years, disease-free survival and overall survival were 94.8% and 98%, respectively.

Conclusions

Weekly ultra-hypo fractionated partial breast RT seems feasible and effective. Toxicity was mild, local control was acceptable, and overall survival was 98% at 3 years. Rates of severe toxicity were reduced with the IMRT technique.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.