Is the toxicity of breast radiotherapy higher in patients with collagen vascular disease? A systematic review of the literature.

Abstract

e12527 Background: Collagen vascular disease (CVD) has been described to be a relative contraindication for radiotherapy (RT) due to increased toxicity. As a result, RT to the breast or chest wall is underutilized in patients with CVD, despite known benefits in local control and overall survival after breast conserving surgery or mastectomy. We sought to characterize the acute and late toxicity rates associated with curative-intent RT for breast cancer patients with CVD. Methods: A systematic review per the PRISMA guidelines was performed using Pubmed database (inception to July 2019), for English-language articles. Key search themes included collagen vascular disease, connective tissue disease, including specific subtypes, along with terms for radiation and cancer. Title and abstract review were followed by full-text review. Inclusion criteria were reports of toxicity of five or more patients with CVD and treatment with curative-intent RT to the breast or chest wall. Data abstracted included: type of study, CVD diagnosis, number of patients who received breast RT, acute grade ≥3, and late grade ≥1, grade ≥3, and grade 5 toxicity. Primary endpoint was late grade ≥3 toxicity for patients with pre-existing CVD. Acute and late toxicity were classified as per CTCAE version 5.0. Results: The initial search yielded 3286 unique abstracts. 34 articles were determined appropriate for full-text review. From these, a final set of 10 articles met all inclusion criteria. All studies were retrospective. In these studies, more than 30 000 patient cases were reported. 184 patients with CVD who underwent curative-intent RT to the breast or chest wall and had available toxicity data were identified, including 128 patients with CVD diagnosed before RT. In the 5 case control studies, 100 patients were matched to 225 controls. Most studies did not report the incidence of all grades of toxicity. Among patients with available data, 7/102 patients (7%) with pre-existing CVD had late grade ≥3 toxicity, including 4/6 (67%) with pre-existing scleroderma and 3/96 (3%) with pre-existing non-scleroderma CVD. 32/88 patients (36%) with pre-existing CVD and available data had late grade ≥1 toxicity. 1/142 (1%) had late grade 5 toxicity, in the form of chronic pericarditis. 6/66 patients (11%) with pre-existing CVD had acute grade ≥3 radiation dermatitis. No patients had acute grade 5 toxicity. Conclusions: Retrospective data suggest that patients with pre-existing CVD, aside from scleroderma, have acceptable acute and late toxicity rates after RT to the breast or chest wall.