Simultaneous Integrated Boost Irradiation After Breast-Conserving Surgery: Physician-Rated Toxicity and Cosmetic Outcome at 30 Months’ Follow-Up
Menée sur 940 patients atteints d'un cancer du sein de stade 0-III et ayant reçu un traitement chirurgical conservateur entre 2005 et 2010, cette étude évalue, après 30 mois de suivi, la toxicité et les résultats esthétiques d'une radiothérapie conformationnelle tridimensionnelle en combinaison avec une irradiation additionnelle du lit tumoral ("boost")
To evaluate toxicity and cosmetic outcome (CO) in breast cancer survivors treated with three-dimensional conformal radiotherapy with a hypofractionated, simultaneous integrated boost (3D-CRT-SIB) and to identify risk factors for toxicity, with special focus on the impact of age. Included were 940 consecutive disease-free patients treated for breast cancer (Stage 0–III) with 3D-CRT-SIB, after breast-conserving surgery, from 2005 to 2010. Physician-rated toxicity (Common Terminology Criteria for Adverse Events version 3.0) and CO were prospectively assessed during yearly follow-up, up to 5 years after radiotherapy. Multivariate logistic regression analyses using a bootstrapping method were performed. At 3 years, toxicity scores of 436 patients were available. Grade ≥2 fibrosis in the boost area was observed in 8.5%, non-boost fibrosis in 49.4%, pain to the chest wall in 6.7%, and fair/poor CO in 39.7% of cases. Radiotherapy before chemotherapy was significantly associated with grade ≥2 boost fibrosis at 3 years (odds ratio [OR] 2.8, 95% confidence interval [CI] 1.3–6.0). Non-boost fibrosis was associated with re-resection (OR 2.2, 95% CI 1.2–4.0) and larger tumors (OR 1.1, 95% CI 1.0–1.1). At 1 year, chest wall pain was significantly associated with high boost dosage (OR 2.1, 95% CI 1.2–3.7) and younger age (OR 0.4, 95% CI 0.2–0.7). A fair/poor CO was observed more often after re-resection (OR 4.5, 95% CI 2.4–8.5), after regional radiotherapy (OR 2.9, 95% CI 1.2–7.1), and in larger tumors (OR 1.1, 95% CI 1.0–1.1). Toxicity and CO are not impaired after 3D-CRT-SIB. Fibrosis was not significantly associated with radiotherapy parameters. Independent risk factors for fibrosis were chemotherapy after radiotherapy, re-resection, and larger tumor size. Re-resection was most predictive for worse CO. Age had an impact on chest wall pain occurrence.
International Journal of Radiation Oncology, Biology, Physics