Stereotactic Ablative Body Radiotherapy for PSMA-PET/CT Staged, Oligometastatic Prostate Cancer - A Multi-Centre Study - Beyond the Abstract

The widespread adoption of PSMA-PET has redefined how we detect oligometastatic prostate cancer (omPC), renewing interest in metastasis-directed therapy such as stereotactic ablative body radiotherapy (SABR). While randomized data are emerging, real-world multicentre series remain critical to understanding how PSMA staging and SABR perform outside clinical trials — and whether SABR meaningfully delays systemic therapy.

In this largest-to-date PSMA-PET–staged retrospective series (n=213, median follow-up ~58 months) and majority only 1-2 oligometastasis, SABR produced a median ADT-free survival of ~42 months, with 37.5% of patients remaining ADT-free at 5 years. Biochemical failure-free survival at 12, 24, and 36 months was modest (46%, 26%, 19%), while clinical failure-free survival remained higher (71%, 50%, 39%), suggesting that many biochemical relapses did not necessitate immediate systemic escalation. Most lesions treated were nodal or osseous, and only 13% of patients received concurrent ADT.

Clinical Implications:

  • SABR following PSMA-PET staging can provide a clinically meaningful ADT-free interval of over three years, delaying systemic therapy and its associated quality-of-life impacts.
  • While biochemical recurrence is common, not all PSA rises warrant systemic therapy — reinforcing the need for individualised surveillance and selective re-intervention.
  • Optimal patient selection remains key: those with limited nodal or bone-only disease and favourable biology are most likely to benefit.
Limitations & Future Directions:

As a retrospective series, the study lacks a randomized comparator and did not control for initiation of ADT. Future trials will assess improved staging (whole-body PET, new PSMA tracers) and integration with systemic therapy, including lutetium-PSMA, will refine the role of SABR in omPC.

Take-Home:

In well-selected, PSMA-PET–staged omPC, SABR is an effective strategy to postpone systemic therapy for years, with outcomes supporting its growing role in metastasis-directed management.

Disclosure: The authors declare no competing interests related to this commentary.

Written by:

  • Isabelle Schupak, GenesisCare, St. Vincent's Hospital, Fitzroy, Victoria, Australia; Olivia Newton-John Cancer Wellness & Research Centre (Austin Health), Heidelberg, Victoria, Australia
  • Michael Ng, GenesisCare, St. Vincent's Hospital, Fitzroy, Victoria, Australia; Faculty of Medicine, The University of Melbourne, Carlton, Victoria, Australia
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