Local Ablative Radiation for Oligometastatic Prostate Cancer

Germany: Local ablative radiation (aRT) for oligometastatic prostate cancer (PCa) has shown great promise and has been a focus of current clinical research. In a new trial, it was discovered that aRT is safe and that one of five patients achieved midterm prostate-specific antigen (PSA) progression and androgen deprivation therapy (ADT)-free duration. The findings of this study were published in European Urology Oncology on 13th November 2021.

Tobias Holscher and the team conducted this study with the objective to check whether aRT is safe and effective in oligometastatic PCa patients with gallium-68 prostate-specific membrane antigen targeted positron emission tomography (PSMA-PET).

This study was designed as a nonrandomized, prospective, investigator-initiated phase 2 trial. From 2014 to 2018, two German hospitals enrolled patients with oligometastatic PCa (five or fewer lymph node or osseous metastases) following local curative treatment, without severe comorbidities or androgen deprivation therapy (ADT). aRT was used to treat all PSMA-PET-positive metastases. The primary goal was to detect treatment-related toxicity (grade 2) 24 months after aRT.

Time to progression of prostate-specific antigen (PSA) and time to ADT were key secondary endpoints that were related to putative prognostic markers using Cox regression.

Among the 72 patients, 63 received aRT (13% dropout rate), and the average length of follow-up was 37.2 months.

Two years following therapy, no treatment-related grade 2 toxicity was reported.

The median duration between PSA progression and ADT was 13.2 and 20.6 months, respectively.

After 3 years, 21.4% of the patients were free of PSA progression.

Conclusion

In conclusion, local aRT is well tolerated in selected individuals with PSMA-PET-staged oligometastatic PCa and may postpone disease development and the initiation of systemic treatment. At three years, one out of every five patients has not progressed. The start of randomized controlled studies with therapeutically relevant objectives seems promising.

Reference

Tobias Hölscher, Michael Baumann, Jörg Kotzerke, Klaus Zöphel, Frank Paulsen, Arndt-Christian Müller, Daniel Zips, Lydia Koi, Christian Thomas, Steffen Löck, Mechthild Krause, Manfred Wirth, Fabian Lohaus. Toxicity and Efficacy of Local Ablative, Image-guided Radiotherapy in Gallium-68 Prostate-specific Membrane Antigen Targeted Positron Emission Tomography–staged, Castration-sensitive Oligometastatic Prostate Cancer: The OLI-P Phase 2 Clinical Trial. DOI: https://doi.org/10.1016/j.euo.2021.10.002