In a patient with M0CRPC with PSA doubling time < 6 months, will you wait until the absolute PSA value is >2, or is PSADT alone sufficient to start an AR targeted agent?

The SPARTAN trial required patients to have evidence of PSA progression per Prostate Cancer Working Group 2 (PCWG2) criteria at the time of enrollment. Per PCWG2 criteria, the PSA must be ≥25% and ≥2 ng/ml above the nadir, and it must be confirmed to be rising ≥3 weeks later. Similar eligibility criteria were used in the M0 CRPC studies testing enzalutamide and darolutamide. As such, I would not use a next-generation androgen receptor signaling inhibitor to treat someone with non-metastatic pros...

Yes, it is reasonable to treat a patient with M0 CRPC with one of the new antiandrogen agents even if his most recent PSA is only 1 ng/mL or 2 ng/mL. However, the accuracy of calculating PSADT decreases when PSA levels are less than 1 ng/mL. Also, the majority of patients with M0 CRPC and PSA levels below 5 ng/mL will not have metastases on conventional imaging. Therefore, my practice is to generally wait until the PSA level is somewhere between 3 ng/mL and 5 ng/mL before beginning apalutamide/d...

I would agree with @Dr. First Last and @Dr. First Last, but simply add a caveat of considering the patient's initial Gleason score and PSA at diagnosis. Those with high grade disease and low PSAs are at higher risk for prostate cancer specific mortality (with more neuroendocrine features and also less likely to respond to ADT). So, in those cases I might consider treatment at a lower PSAs compared to the more typical adenocarcinomas with higher presenting PSAs.