Top Line: Does radiation delay the initiation of ADT in patients with oligometastatic, castration sensitive prostate cancer.
The Study: RadSABR was a single center, phase 2 trial that sought to determine if the combination of SBRT and radium-223 could be used to treat bone-only oligometastatic prostate cancer without the need for ADT. It included 20 patients who had bone-only oligometastatic disease after definitive treatment of the primary and pelvic nodes. They received 6 cycles of radium-223 and SABR to all sites of disease between the first and second cycles. The recommended SABR dose was 30 Gy in 5 fractions. Radium-223 was discontinued if there was a >10% rise in PSA from baseline (if baseline >20) or if the PSA rose to >20 in those with a baseline <20. The rate of freedom from ADT was 50% at 15 months and 40% at 24 months. In over half of patients (55%), the PSA declined by >50%, and 25% had a PSA decline >90%. Two patients (10%) had an undetectable PSA at 2 years. The rate of grade 3 toxicity was 10%, but no patients reported a significantly decline in quality of life.
TBL: In this small, single center trial, half of patients with bone-only oligometastatic prostate cancer were free from ADT after treatment with SBRT and radium-223. | Tward, Int J Radiat Oncol Biol Phys 2025
The Study: RadSABR was a single center, phase 2 trial that sought to determine if the combination of SBRT and radium-223 could be used to treat bone-only oligometastatic prostate cancer without the need for ADT. It included 20 patients who had bone-only oligometastatic disease after definitive treatment of the primary and pelvic nodes. They received 6 cycles of radium-223 and SABR to all sites of disease between the first and second cycles. The recommended SABR dose was 30 Gy in 5 fractions. Radium-223 was discontinued if there was a >10% rise in PSA from baseline (if baseline >20) or if the PSA rose to >20 in those with a baseline <20. The rate of freedom from ADT was 50% at 15 months and 40% at 24 months. In over half of patients (55%), the PSA declined by >50%, and 25% had a PSA decline >90%. Two patients (10%) had an undetectable PSA at 2 years. The rate of grade 3 toxicity was 10%, but no patients reported a significantly decline in quality of life.
TBL: In this small, single center trial, half of patients with bone-only oligometastatic prostate cancer were free from ADT after treatment with SBRT and radium-223. | Tward, Int J Radiat Oncol Biol Phys 2025