278P - Full-coverage radiotherapy for prostate cancer patients with oligometastases

Background

Radiotherapy is an effective treatment option for local control of prostate cancer, but its role in the treatment of oligometastatic prostate cancer (omPCa) remains unclear. This study aimed to investigate the potential survival benefit of full-coverage radiotherapy in patients with omPCa.

Methods

A retrospective analysis was conducted on patients with omPCa who received full-coverage radiotherapy between July 2012 and June 2022. Full-coverage radiotherapy was defined as radiotherapy to all lesions, including the primary site and metastatic lesions. Overall survival (OS) was the primary endpoint, and biochemical progression-free survival (bPFS) and radiological progression-free survival (rPFS) were the secondary endpoint. The Kaplan-Meier method was used to estimate univariate analysis, and the log-rank test was used to conduct multivariate analysis.

Results

A total of 33 patients, including 31 de novo oligometastatic hormone-sensitive prostate cancer (omHSPC) patients and 2 oligometastatic castration-resistant prostate cancer (omCRPC) patients, were enrolled in the study. The median follow-up was 38.8 months (range: 4.2–70.6 months). The survival rates at 2, 3, and 5 years were 100%, 95.7%, and 81.2%, respectively. The median bPFS was 58.9 months (95% CI: 47.7 - 70.1 months). The median rPFS is 55.3 months (95% CI: 39.9 -70.8 months). According to the univariate analysis, TURP prior to radiotherapy, presence of symptoms related to the lesions, and the pre-radiotherapy status of CRPC were associated with poorer survival. Multivariate analysis showed EBRT synchronized with ADT or chemotherapy (p=0.016), non-CRPC status before radiotherapy(p=0.000), and PSA levels more than 1 ng/ml before radiotherapy ( p=0.014) may be associated with longer rPFS. Both univariate and multivariate studies have demonstrated that the coexistence of lymph node and bone metastases is associated with a higher risk of biochemical recurrence (p=0.02). The occurrence of acute adverse reactions of Grade 3 or higher was not observed.

Conclusions

Full-coverage radiotherapy with an optimistic bPFS and rPFS may improve the OS of patients with oligometastatic prostate cancer. Further prospective studies are warranted to confirm the findings of this retrospective analysis.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Department of Radiation Oncology, Shanghai Changhai Hospital, the Naval Medical Universit.

Funding

The First Affiliated Hospital of Navy Medical University “234 Subject Climbing Program” (2019YPT004), the First Affiliated Hospital of Naval Medical University “Youth Development Program”(2021JCQNO3).

Disclosure

All authors have declared no conflicts of interest.