X. Qi, H. Z. Li, and X. S. Gao; Department of Radiation Oncology, Peking University First Hospital, Beijing, China
Purpose/Objective(s): Currently, guidelines recommend radiotherapy (RT) to only primary tumor for oligo-metastatic hormone-sensitive prostate cancer (omHSPC). The aim of this study was to evaluate the safety and survival in oligometastatic prostate cancer patients treated with RT for both primary tumor and all metastatic lesions. Here we report the 5-year results. Materials/
Methods: This single-center ambispective cohort study (PROLONG Study) analyzed 395 patients from 10/2011 to 1/2022. Inclusion criteria: 1. Pathologically confirmed prostate cancer; 2. Imaging revealed distant metastasis (non-regional lymph node metastasis/bone metastasis/visceral metastasis). 3.=10 metastases or active metastases. The exposure factor was total consolidative therapy (TCT). De-novo oligo-metastatic (53.7%), oligo--recurrent (14.7%), oligo--progressive (26.6%), and oligo--persistent (1.8%). Daily image-guided rotational intensity modulated radiotherapy (IGRT-VMAT) was used. Kaplan–Meier method, log rank test and cox regression were used to calculate overall survival (OS) and progression-free survival (PFS). PFS included PSA failure, local or distant failure assessed by imaging. Results: The median BED3 of primary tumor was 135.3Gy (IQR: 128.3-135.3Gy). A total of 718 metastases were irradiated, and the median BED3 of metastases was 121.3Gy (IQR: 113.3-131.3Gy). Up to 1/2024, the median time from diagnosis to last follow-up or death was 60 months (IQR: 41-83 months). A total of 115 patients died. The 3-year OS and 5-year OS were 93.2% and 79.5%, respectively. Median OS was 102 months. Multivariate results showed that GS score and PSA at diagnosis were independent prognostic factors of OS. Acute genitourinary (GU) toxicities: G1 (38.7%), G2 (4.1%), G3 (0.5%). Acute gastrointestinal (GI) toxicities: G1 (40.0%), G2 (4.3%) , G3 (0.3%). According to the timing of radiotherapy, the patients were divided into four subgroups: ?De-novo oligo-metastasis subgroup: the median OS and PFS were not reached. Multivariate results showed that patients with higher initial PSA or T1/2 were found to have improved PFS. ?Oligo-recurrence subgroup: the median OS was not reached and the median PFS was 37 months. Multivariate results showed that initial PSA level and hormonal status (HSPC/CRPC) were independent prognostic factors for PFS. ?Oligo-progressive subgroup: the median OS was 85 months (95%CI: 65-105 months), median PFS was 11 months (95%CI: 8.5-13.5 months). Multivariate results showed that pelvic irradiation alone was an independent prognostic factor for PFS. ?Oligo-persistence subgroup: the median OS and PFS were not reached. Conclusion: The 5-year results showed that TCT tolerability was excellent. RT for the primary tumour and all metastatic lesions has better survival than clinical studies of prostate radiotherapy alone, especially for patients with HSPC, shorter interval between diagnosis and RT and lower metastatic burden/volume.
