Top Line: A slam dunk indication for SBRT is prolonging survival and time to systemic therapy for oligometastatic prostate cancer.
The Study: Still, it remains unclear if initiating systemic therapy upfront with SBRT can maximize survival times further. The randomized phase 2 RADIOSA trial evaluated the incremental benefit of adding short-course (6 months) androgen deprivation therapy (ADT) to stereotactic body radiotherapy (SBRT) alone for oligorecurrent (≤3 sites) castrate-sensitive prostate cancer. The SBRT regimen was typically 30 Gy in 3 fractions delivered every other day “or equivalent regimens depending on disease site location.” The most common sites were the pelvic nodes (39%), bones (36%), and extrapelvic nodes (25%). Across 102 patients randomized to SBRT alone or SBRT + ADT, the addition of short-course ADT more than doubled the primary endpoint of radiographic progression-free survival from 15 to 32 months. This is…unsurprising, especially considering a rise in PSA no doubt prompted much of this imaging. The discrepancy was driven by out-of-field failures that were noted in 61% without ADT versus 37% with ADT. And this, unsurprisingly, was seen primarily among those with the highest risk recurrences (read: PSA >2, shorter interval from initial therapy, extra-pelvic disease, etc). Since median time to testosterone recovery from initiation of ADT was 9 months, there was less of a discrepancy in median progression-free survival with normal testosterone levels: 15 versus 22 months with ADT.
TBL: “SBRT and short-course ADT might be a good option for some patients, being a compromise between single modality (only ADT or only SBRT) and intensified systemic therapy”…particularly those with high risk oligometastatic recurrence. | Marvaso, Lancet Oncol 2024
The Study: Still, it remains unclear if initiating systemic therapy upfront with SBRT can maximize survival times further. The randomized phase 2 RADIOSA trial evaluated the incremental benefit of adding short-course (6 months) androgen deprivation therapy (ADT) to stereotactic body radiotherapy (SBRT) alone for oligorecurrent (≤3 sites) castrate-sensitive prostate cancer. The SBRT regimen was typically 30 Gy in 3 fractions delivered every other day “or equivalent regimens depending on disease site location.” The most common sites were the pelvic nodes (39%), bones (36%), and extrapelvic nodes (25%). Across 102 patients randomized to SBRT alone or SBRT + ADT, the addition of short-course ADT more than doubled the primary endpoint of radiographic progression-free survival from 15 to 32 months. This is…unsurprising, especially considering a rise in PSA no doubt prompted much of this imaging. The discrepancy was driven by out-of-field failures that were noted in 61% without ADT versus 37% with ADT. And this, unsurprisingly, was seen primarily among those with the highest risk recurrences (read: PSA >2, shorter interval from initial therapy, extra-pelvic disease, etc). Since median time to testosterone recovery from initiation of ADT was 9 months, there was less of a discrepancy in median progression-free survival with normal testosterone levels: 15 versus 22 months with ADT.
TBL: “SBRT and short-course ADT might be a good option for some patients, being a compromise between single modality (only ADT or only SBRT) and intensified systemic therapy”…particularly those with high risk oligometastatic recurrence. | Marvaso, Lancet Oncol 2024