Progression of Index Metastases in Oligometastatic Hormone-Sensitive Prostate Cancer: Implications for Metastasis-Directed Therapy?

Background: For de-novo oligometastatic prostate cancer (omHSPC) treated with standard of care androgen suppression and prostate radiotherapy, the patterns of progression vis-a-vis index metastatic sites are not well understood. Methods: This single centre study included patients with de-novo omHSPC (CHAARTED criteria) staged with a PSMA-PET/CT scan at diagnosis, treated with androgen suppression and prostate radiotherapy, and re-staged with PSMA-PET/CT at biochemical progression. Disease status at index oligometastases was noted at progression. Results: From 2015 to 2024, 79 patients with omHSPC were found eligible (M1a = 22, M1b = 57). Over a median follow-up of 39 months (IQR 28-69), 15 patients (19%) had disease progression. Restaging PSMA-PET/CT revealed progression of the index oligometastases for 11/15 patients (73%), with additional metastases in 7 of these. Conclusion: The high proportion of progression at the index oligometastases supports the potential benefit of metastasis-directed therapy for local ablation.