Phase II clinical trial results – SBRT for oligometastatic, hormone-resistant prostate cancer
This phase II clinical trial (ARTO trial) examined whether adding stereotactic body radiation therapy (SBRT) to a standard treatment of abiraterone acetate and prednisone (AAP) would help improve outcomes for patients with oligometastatic, castrate- resistant prostate cancer (CRPC). Oligometastatic CRPC refers to prostate cancer that has spread but only to a limited number of sites—three or fewer—and these sites are not in major organs like the liver or lungs.
In the trial, 157 patients who met the criteria were randomly divided into two groups. One group received only AAP, while the other group received both AAP and SBRT. The main goal was to see how many patients experienced a biochemical response meaning their PSA levels, which help track cancer activity, dropped by at least 50% after six months. The study also looked at complete biochemical response, which meant the PSA level dropped below 0.2 ng/mL, and progression-free survival, or how long patients lived without their cancer getting worse.
The results showed that patients who received the combination of AAP and SBRT had better outcomes. Specifically, 92% of the patients in the experimental group (AAP plus SBRT) had a biochemical response, compared to only 68.3% in the group that received AAP alone. For complete biochemical response, 56% of the patients in the experimental group reached this goal, while only 23.2% did in the control group. Additionally, the experimental group had better progression-free survival, meaning their cancer stayed under control for a longer period.
Overall, the authors concluded that adding SBRT to AAP significantly improved cancer control and delayed its progression, offering a promising treatment strategy for patients with oligometastatic CRPC.
J Clin Oncol. 2023 Dec 20;41(36):5561-5568. doi: 10.1200/JCO.23.00985. Epub 2023 Sep 21.
