Hypofractionated radiotherapy after conservative surgery may increase low-intermediate grade late fibrosis in breast cancer patients

patients Abstract Fulltext Metrics Get Permission Cite this article Authors Digesù C, Deodato F, Macchia G, Cilla S, Pieri M, Zamagni A, Farioli A, Buwenge M, Ferrandina G, Morganti AG Received 12 March 2018 Accepted for publication 23 May 2018 Published 3 October 2018 Volume 2018:10 Pages 143—151 DOI https://doi.org/10.2147/BCTT.S167914 Checked for plagiarism Yes Review by Single-blind Peer reviewer comments 3 Editor who approved publication: Professor Pranela Rameshwar Article has an altmetric score of 2 Cinzia Digesù,1 Francesco Deodato,1 Gabriella Macchia,1 Savino Cilla,2 Martina Pieri,3 Alice Zamagni,4 Andrea Farioli,5 Milly Buwenge,4 Gabriella Ferrandina,6,* Alessio G Morganti4,* 1Radiotherapy Unit, General Oncology Unit, Fondazione Giovanni Paolo II, Campobasso, Italy; 2Medical Physics Unit, Fondazione Giovanni Paolo II, Campobasso, Italy; 3Radiotherapy Unit, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori, Meldola, Italy; 4Radiation Oncology Center, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy; 5Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy; 6Department of Woman and Child Health, Gynecologic Oncology Unit, Fondazione “Policlinico Universitario A. Gemelli”, IRCSS, Universita’ Cattolica Sacro Cuore, Rome, Italy *These authors contributed equally to this work Aim: To compare late toxicity after postoperative hypofractionated radiotherapy (RT) and standard fractionated RT in patients with early-stage breast carcinoma. Methods: This retrospective study included 447 patients (Modulated Accelerated Radiotherapy [MARA-1]: 317 patients, and control group [CG]: 130 patients). In the CG, the whole breast received 50.4 Gy in 28 fractions (fx) using 3D-radiotherapy, plus a sequential electron boost (10 Gy in 4 fx) to tumor bed. In MARA-1 group, a forward-planned intensity-modulated radiotherapy technique with 40 Gy in 16 fx with a concomitant boost of 4 Gy to breast was used. The primary endpoint was to evaluate late toxicity, and secondary endpoints were acute toxicity, local control, and survival. ClinicalTrials.gov: NCT03461224. Results: Median follow-up was 52 months (range: 3–115 months). Late skin and subcutaneous toxicity were acceptable: 5-year actuarial cumulative incidence of Grade (G) 3 late skin toxicity was 1.5% in CG and 0.0% in MARA-1. Five-year actuarial cumulative incidence of G3 late subcutaneous toxicity was 0.8% in CG and 0.3% in MARA-1. On multivariate analysis, tobacco smoking and planning target volume were associated with an increased risk of late G1 skin toxicity (HR: 2.15, 95% CI: 1.38–3.34 and HR: 1.12, 95% CI: 1.07–1.18, respectively), whereas patients with a larger planning target volume also showed an increased risk of G1 and G2 late subcutaneous toxicity (HR: 1.14, CI 95%: 1.08–1.20 and HR: 1.14, 95% CI: 1.01–1.28, respectively). MARA-1 patients also showed an increased risk of late G1 and G2 subcutaneous toxicity (HR: 2.35, 95% CI: 1.61–3.41 and HR: 3.07, 95% CI: 1.11–8.53, respectively) compared to CG. Conclusion: In this retrospective analysis, postoperative accelerated-hypofractionated RT for early-stage-breast carcinoma was associated with higher incidence of subcutaneous side effects. However, this increase was limited to G1–G2 toxicity. In the future, development of predictive models could help in tailoring dose and fractionation based on the risk of toxicity.