Stereotactic Body Radiotherapy for Oligometastatic Prostate Cancer
Menée à partir de données portant sur 66 patients atteints d'un cancer de la prostate avec oligométastases, cette étude évalue, du point de vue du contrôle des métastases, de la survie sans progression biochimique et de la survie globale, l'efficacité d'une radiothérapie corporelle stéréotaxique ciblant les métastases
Purpose/Objective(s) : To review outcomes of patients with oligometastatic prostate cancer (PCa) treated with stereotactic body radiotherapy (SBRT) and to identify variables associated with local failure. Methods and Materials : We retrospectively reviewed records of patients treated with SBRT for oligometastatic PCa. Metastasis control (i.e. control of the treated lesion, MC), biochemical progression-free survival (BPFS), distant progression-free survival (DPFS), and overall survival (OS) were estimated with the Kaplan-Meier method. Results : Sixty-six men with 81 metastatic PCa lesions, 50 of which were castrate-resistant, were included in the analysis. Lesions were in bone (n=74), lymph nodes (n=6), or liver (n=1). SBRT was delivered in 1 fraction to 71 lesions (88%), at a median dose of 16 Gy (range, 16-24 Gy). The remaining lesions received 30 Gy in 3 fractions (n=6) or 50 Gy in 5 fractions (n=4). Median follow-up was 16 months (range, 3-49 months). Estimated MC at 2 years was 82%. BPFS, DPFS, and OS were 54%, 45%, and 83%, respectively. On multivariate analysis, only the dose of SBRT was significantly associated with MC; lesions treated with 16 Gy had 58% MC and those treated with ≥18 Gy had 95% MC at 2 years (P≤.001). At 2 years, MC for lesions treated with 18 Gy (n=21) was 88%. No patient treated with ≥18 Gy in a single fraction or with any multi-fraction regimen had local failure. Six patients (9%) had grade 1 pain flare, and 2 (3%) had grade 2 pain flare. No grade 2 or greater late toxicities were reported. Conclusions : SBRT for patients with oligometastatic prostate cancer provided optimal metastasis control and acceptable toxicity with doses ≥18 Gy. BPFS was 54% at 16 months with the inclusion of SBRT in the treatment regimen. SBRT should be considered in patients with castration-refractory, oligometastatic prostate cancer who have limited options for systemic therapy.