Once-Daily Postmastectomy Radiation Therapy Confers Excellent Locoregional Control for Inflammatory Breast Cancer
Menée à l'aide de données portant sur 213 patientes atteintes d'un cancer inflammatoire du sein de stade III (durée médiane de suivi : 3,5 ans), cette étude analyse le taux de récidive locorégionale isolée et la survie sans maladie après une radiothérapie post-mastectomie hyperfractionnée une fois par jour
Background : For patients with cT4dM0 inflammatory breast cancer (IBC), improved locoregional control has been reported following modern trimodality therapy that includes hyperfractionated/twice-daily postmastectomy radiotherapy (PMRT). We evaluated survival outcomes in a contemporary cohort of patients with IBC routinely treated with once-daily PMRT.
Methods : We retrospectively identified 213 patients with stage III IBC treated with neoadjuvant systemic therapy, modified radical mastectomy, and PMRT from January 2006 to December 2022 at a single institution. Routinely, PMRT included 50 Gy in 18–25 daily fractions to the chest wall and regional nodes with a 0.5–1.0 cm skin bolus. We calculated the crude rate of isolated locoregional recurrence (LRR) and estimated disease-free survival (DFS) using Kaplan-Meier survival curves and a Cox proportional hazard regression model.
Results : Median follow-up was 3.5 years (IQR, 1.8–6.3 years). Isolated LRR was observed in 1.8% (4/213) of patients at a median of 10.6 months (IQR, 8.8–18.4 months). LRR with or without a distant failure occurred in 22 patients (10.3%). All LRRs were observed in patients who did not achieve pathologic complete response (pCR) (n = 148). Distant metastasis occurred in 32% (69/213) of patients and 57 deaths were recorded. On multivariable analysis, triple-negative subtype (hazard ratio [HR], 3.16; 95% CI, 1.56–6.41; P = 0.001), lobular histology (HR, 2.45; 95% CI, 1.10–5.45; P = 0.027), and nodal pCR (HR, 0.27; 95% CI, 0.15–0.49; P < 0.001) were associated with DFS. Subgroup analysis demonstrated no difference in DFS between biologic subtypes in patients with pCR (P = 0.29).
Conclusions : Once-daily PMRT confers excellent locoregional control in patients with IBC, as evidenced by low rates of isolated LRR at 3.5 years of follow-up. Worse overall LRR and DFS among patients with triple-negative subtype and residual nodal disease warrants consideration of local therapy escalation with boost and underscores the need for novel systemic therapies for IBC.
International Journal of Radiation Oncology*Biology*Physics , résumé, 2025