A brief discussion on best practices in monitoring patients on therapy for nonmetastatic castration-resistant prostate cancer [nmCRPC].
Alicia Morgans, MD, MPH: Evan, I'm curious, from your perspective, what do you think about in terms of monitoring patients with nonmetastatic CRPC?
Evan Y. Yu, MD: I think the important thing is to say is these patients are coming in regularly anyhow to get their LHRH [luteinizing hormone-releasing hormone] therapy, so I generally tend to give every 3 months depot shots, and when I see those patients, I check their PSA [prostate-specific antigen]. So that's the number one thing I do for monitoring, and I really keep a close tab on their PSA doubling time. Certainly, if I see an inflection point and the slope of the curve start to change, that might be a significant trigger for me to obtain imaging. And if the PSA is rising, and it's starting to become less linear and more exponential, those are some triggers where I might then get imaging and look to see whether the disease status changed or not.
Alicia Morgans, MD, MPH: Well, that's helpful. Do you have any suggestions for people who are concerned about progression radiographically before you see the PSA rising? Is there any sort of standardization to get imaging every 12 months if I haven't done already or anything like that, that you would recommend for clinicians?
Evan Y. Yu, MD: I think a lot of people do that. They get imaging once every 12 months, looking for either neuroendocrine, amphicrine, double negative, and all the aggressive variant subtypes that can result as part of treatment resistance. I think that's a very reasonable standard that a lot of people do annual imaging even if the PSA hasn't significantly risen.
Matthew R. Smith, MD, PhD: I would add that true radiographic progression without PSA progression is vanishingly rare. It's really uncommon. But I would add that I would take any confirmed PSA elevation seriously because patients on these drugs may progress radiographically at much lower PSAs than if they were on ADT [androgen deprivation therapy] alone.
Transcript edited for clarity.