Five-Year Late Toxicity After Ultra-Hypofractionated Whole-Breast Radiotherapy With Simultaneous Integrated Boost: A Prospective Multicentre Cohort Study.

Authors

Maia Dzhugashvili, Escarlata Lopez, Jaume Fernández-Ibiza, Ana Serradilla, Antonio Seral, Sigfredo Romero, Graciela García, Kirill Matskov Malinochka, Lisellot Torres, Daniela Gonsalves, José Begara, Ana Belén Bezares, Álvaro Flores, María Mateos, David Esteban, Daniel Rivas, Jon Andreescu, Castalia Fernandez, Abrahams Ocanto, Loubna Aakki, Francisco Góngora, Alberto Gómez, Eduardo Melian, Juan José De la Cruz Troca, Philip Poortmans, Juan A Barcia, Felipe Couñago

Published in

International journal of radiation oncology, biology, physics. Oct 16, 2026. Epub Oct 16, 2026.

Abstract

Ultra-hypofractionated whole-breast radiotherapy has become an accepted option for early breast cancer, but evidence on the incorporation of a simultaneous integrated boost within a five-fraction schedule remains limited. The present study evaluated five-year late side effects after whole-breast irradiation with a simultaneous integrated boost delivered in five fractions in a prospective multicentre cohort.
This prospective, non-randomized, multicentre cohort included 242 patients with early breast cancer treated between April and December 2020. All patients underwent breast-conserving surgery with clear margins. Whole-breast irradiation was delivered at 26 Gy in five daily fractions, and 157 patients received a simultaneous integrated boost to 29 Gy in five fractions. The primary endpoint was late normal-tissue side effects in the simultaneous integrated boost subgroup, assessed prospectively with clinical examination, photographic documentation, and LENT-SOMA scoring. Comparisons with patients treated without a boost were exploratory.
Median follow-up was 64.7 months in both the overall cohort and the simultaneous integrated boost subgroup, and 221 of 242 patients completed the scheduled five-year visit. In the simultaneous integrated boost subgroup, cumulative any-grade pain was reported in 14.6% of patients at five years, and cumulative any-grade fibrosis in 8.9%. Other late side effects were uncommon, including breast oedema in 5.1%, arm oedema in 0.6%, atrophy in 1.9%, and telangiectasia in 0.6%; no ulceration was observed. In exploratory unadjusted analyses, pain was more frequent in the simultaneous integrated boost group than in the no-boost group, whereas no significant differences were observed for other late side effects. Chemotherapy receipt was also associated with persistent pain in exploratory analyses.
Whole-breast irradiation with a 29 Gy simultaneous integrated boost in five fractions achieved low rates of objective late side effects and reassuring oncological outcomes after more than five years, while shortening treatment to a single one-week course compared with sequential or moderately hypofractionated schedules. Persistent low-grade breast pain was more frequent with the boost, but non-randomized allocation and its association with chemotherapy preclude causal attribution, supporting continued, careful use in selected patients alongside further prospective, randomized studies with baseline symptom assessment.

PMID:
42887678
Bibliographic data and abstract were imported from PubMed on 17 Oct 2026.

Read full publication at:
Please sign in to see all details.

Stats

1-terrible, 9-excellent. How would you rate this publication? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.