nmCRPC: Unmet Needs and Imaging

Matthew R. Smith, MD, PhD:Our standard approach has been to intervene for patients with metastatic CRPC. There are currently 6 FDA-approved therapies in that setting based on modest improvements in overall survival and, for many of the drugs, meaningful improvements in progression-free survival. But, until recently, there has been no comparable evidence showing improved clinical benefits in patients with nonmetastatic CRPC. So, in my view, really the correct approach, up until very recently, has been to observe patients until they develop detectable metastases by conventional imaging.

For patients with nonmetastatic CRPC, my usual approach is to image about every 6 to 12 months, or sooner for patients who have a particularly rapid rate of PSA rise or develop new symptoms that are concerning for disease progression. My usual choice of imaging is bone scan and abdominal pelvic CT scan, and the selection of those studies reflects my desire to identify patients who would have been candidates for the pivotal studies in metastatic CRPC. In other words, if we identify patients with detectable metastases by those imaging modalities, we could then generalize those patients to the pivotal studies that led to approval for drugs in mCRPC.

Now, the really important and interesting point about this is there are certainly newer and emerging more-sensitive imaging modalities that may identify metastases of patients at an earlier time. But in that specific setting, we really don’t know whether the FDA-approved therapies would have the same risk-benefit consideration as they did in the pivotal trial. And we really accept fundamentally that patients with nonmetastatic CRPC, for the most part, are likely to have occult metastases. And many of those patients might have detectable metastases by newer and more-sensitive imaging tests.

Transcript edited for clarity.