Dr. Claire Vale
The meta-analysis was designed to include a consistent definition of PSA-driven EFS, prior to the unblinding of trial results.
The definition of EFS used in the trial was time from randomization until the first evidence of either PSA of 0.4 ng/mL or greater and rising after completion of radiotherapy, clinical/radiological progression, initiation on nontrial treatment, death from prostate cancer following completion of radiotherapy, or PSA level of 2.0 ng/mL or greater any time after randomization.
They analyzed data on a total of 1,074 men assigned to adjuvant radiotherapy and 1,077 assigned to salvage radiotherapy.
In each of the three trials included in the meta-analysis, there was a nonsignificant trend toward better PSA-driven EFS with salvage radiotherapy vs. adjuvant radiotherapy. The overall hazard ratio was 1.12, with the 95% confidence interval crossing 1, indicating a nonsignificant result.
Dr. Vale noted that early salvage radiotherapy spares many men from potentially unnecessary radiation and its negative consequences. Of the men included in the trials, more than 60% of those randomized to observation with salvage radiotherapy have yet to start radiotherapy.
She noted that investigators still need to assess long-term definitive outcomes such as metastases and survival, and whether some patients may derive benefit from adjuvant radiotherapy.
Invited discussant Gert De Meerleer, MD, PhD, a radiation oncologist at University Hospitals Leuven in Belgium, acknowledged that he agreed with most of the findings of the RADICALS-RT and ARTISTIC investigators.
Dr. Gert De Meerleer
An important take-home message, he said, is that “cure is the aim, and radiotherapy the keystone. If you have PSA relapse after prostatectomy, you can say, ‘I don’t treat the patient’ – fair enough. But if you treat the patient, only giving systemic therapy is the wrong way to go, you have to add radiotherapy,” he said.
He also agreed that “salvage is probably the modality of choice, and it is also in a lot of European countries, provided it is early.”
The RADICALS-RT trial is supported by Cancer Research UK and the Medical Research Council UK. Dr. Parker said he had no disclosures relevant to the trial. ARTISTIC is funded by the Medical Research Council. Dr. Vale reported having no disclosures. Dr. De Meerleer reported speaker fees, advisory board activities, and scientific grants not related to the studies.
SOURCE: Parker C et al. and Vale C et al. ESMO 2019. Abstracts LBA49_PR and LBA48_PR.