Stereotactic body radiotherapy for lung oligometastatic prostate cancer: An international retrospective multicenter study

Background: Management of prostate cancer (PCa) patients with lung oligometastases remains unclear in the absence of published data. Objective: The aim of this study was to evaluate the efficacy of Stereotactic Body Radiotherapy (SBRT) in this setting. Design, setting, and participants: We conducted a multicenter retrospective study that included 35 PCa patients treated with SBRT for lung oligometastases in 7 centers across 3 countries. Outcome measurements and statistical analysis: The efficacy was evaluated by the progression free-survival (PFS), defined as pre-SBRT PSA + 25 % or nadir PSA + 25 % and + 2 ng/mL or radiological progression if it occurred before biochemical progression. The local recurrence free-survival (LRFS), distant metastases free-survival (DMFS), Overall Survival (OS) and Androgen Deprivation Therapy free-survival were also assessed. Survival was estimated using the Kaplan Meier method. Results: 35 patients were included with lung oligometastases staged with PET-CT for 97 % and histologically biopsy confirmed for 51 %. 77 % had an oligorecurrent metastatic disease. The median pre SBRT PSA was at 1.7 ng/mL [0.8, 3.0] and the median follow-up after SBRT was 28.7 months. The median PFS was 21.6 months [95 % CI: 21.6; NA] and the median DMFS was 32.4 months [95 %CI: 22.2-NA]. No parameters were significantly associated with PFS on the univariate and multivariate models. For patients who did not start ADT before or concomitantly with SBRT (n =18), the 1-year ADT free-survival rate was estimated at 87.2 % [71.9;100]. Conclusions: SBRT for PCa lung oligometastases offers good oncological outcomes, comparable to those reported for bone and/or lymph node metastases SBRT. Our results encourage the inclusion of patients with lung oligometastatic disease in clinical trials designed to assess the value of SBRT. Patient summary: SBRT for prostate cancer lung oligometastases shows promising results, similar to treatments for bone or lymph node oligometastases.