Marazzi Fabio, Masiello Valeria, Fabi Alessandra, Manfrida Stefania, Corvari Barbara, Lancellotta Valentina, Mazzarella Ciro, Longo Silvia, De Angeli Martina, Moschella Francesca, Di Leone Alba, Orlandi Armando, Bracci Serena, Colloca Giuseppe Ferdinando, Massaccesi Mariangela, Boldrini Luca, Tagliaferri Luca, Bria Emilio, Masetti Riccardo, Franceschini Gianluca, Valentini Vincenzo, Gambacorta Maria Antonietta, Cellini Francesco
Radioterapia Oncologica, Dipartimento di Diagnostica per Immagini, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy.
Unità Operativa Dipartimentale di Medicina di Precisione in senologia, Dipartimento di Scienze della salute della donna, del bambino e di sanità pubblica Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy.
Acta Oncol. 2025 May 19;64:685-692. doi: 10.2340/1651-226X.2025.42933.
Bone metastases occur in up to 75% of metastatic breast cancer (MBC) cases. Advances in imaging now allow earlier detection, even during the oligometastatic phase. Radiotherapy (RT) is increasingly used in asymptomatic patients with ≤5 bone lesions, however standardised guidelines for dose and target volumes remain lacking. This study evaluates the outcomes of a simultaneous integrated boost (SIB) using intensity-modulated radiotherapy (IMRT) to deliver ablative doses to macroscopic bone lesions.
This retrospective study analysed MBC patients treated with SIB-IMRT for bone metastases between January 2014 and January 2022. The primary endpoint was freedom from local progression (FFLP); secondary endpoints included disease progression after radiotherapy (DP-AR) and overall survival (OS). Subgroup analyses were performed according to age, immunophenotype, and line of therapy.
Among 954 patients treated with RT, 85 received SIB-IMRT (6-8 Gy per fraction, 5 fractions). Median follow-up was 41 months. Nineteen patients (22.4%) had a single bone metastasis, 23.5% were oligometastatic, and 54.1% were plurimetastatic. Median FFLP was 17 months; only 7% experienced local relapse at the SIB site. While DP-AR was 13.2 months, median OS reached 82.7 months. No significant correlation was found between local relapse and age, immunophenotype, or systemic therapy. Immunophenotype significantly influenced DP-AR (p = 0.002), while DP-AR and OS were not significantly associated with local progression.
SIB-IMRT for bone metastases in MBC is feasible and effective, with encouraging local control and minimal toxicity. Prospective studies are warranted to optimise dose escalation and explore synergistic effects with systemic therapies.
骨转移发生在高达75%的转移性乳腺癌（MBC）病例中。现在影像学的进展使得能够更早地检测到骨转移，甚至在寡转移阶段。放射治疗（RT）越来越多地用于无症状且骨转移灶≤5个的患者，然而对于剂量和靶区体积仍缺乏标准化指南。本研究评估了使用调强放射治疗（IMRT）进行同步整合加量（SIB）以向宏观骨转移灶给予消融剂量的疗效。
这项回顾性研究分析了2014年1月至2022年1月期间接受SIB-IMRT治疗骨转移的MBC患者。主要终点是无局部进展生存期（FFLP）；次要终点包括放疗后疾病进展（DP-AR）和总生存期（OS）。根据年龄、免疫表型和治疗线数进行亚组分析。
在954例接受放疗的患者中，85例接受了SIB-IMRT（每分次6-8 Gy，共5次）。中位随访时间为41个月。19例患者（22.4%）有单个骨转移，23.5%为寡转移，54.1%为多转移。中位FFLP为17个月；仅7%的患者在SIB部位出现局部复发。DP-AR为13.2个月，中位OS达到82.7个月。未发现局部复发与年龄、免疫表型或全身治疗之间存在显著相关性。免疫表型对DP-AR有显著影响（p = 0.002），而DP-AR和OS与局部进展无显著关联。
SIB-IMRT用于MBC骨转移是可行且有效的，具有令人鼓舞的局部控制效果且毒性极小。有必要开展前瞻性研究以优化剂量递增并探索与全身治疗的协同效应。
