Salvage radiation is still considered standard of care for patients with biochemical recurrence after prostatectomy even when PET imaging is negative. But many patients and even physicians can’t help but wonder, is radiation to the fossa still beneficial if a PSMA PET is negative? In this multicenter, retrospective study, 341 patients who had PSMA PET and salvage radiation (no elective nodal coverage, no ADT) were compared. One group had a completely negative PET while the other had PSMA positive local recurrence only. Those with nodal or distant metastasis were excluded. At 3 years, biochemical PFS was significantly lower in those with a negative PET (71.6% v 80.8%). Interesting differences between groups included a higher median dose in the PET positive group as many physicians gave an additional boost to gross disease, and in that group, dose to the fossa was associated with biochemical control. Another finding was that many patients who were initially PET negative but recurred were found to have nodal metastases. So, PET negative patients still have a very good BPFS with salvage RT to the fossa alone. However, as other trials suggest, the chances of salvage may be higher with ADT and pelvic nodal coverage. | Scharl, Radiother Oncol 2023
