An expert in prostate cancer discusses the typical follow-up and monitoring approaches for a patient with metastatic CRPC.
Matthew R. Smith, MD, PhD: In my practice, the main state of monitoring is a serial measurement of PSA. Typically, serum PSA is measured every 3 months while [a patient is] on androgen deprivation therapy. Then, in a patient with an appropriate response, as in this case, we would repeat imaging after 1 year to establish a new baseline and to exclude the remote possibility of cancer progression despite a lower, undetectable PSA.
There are a number of metrics that we use to inform decision-making about addition or changes in systemic treatment. Rise in PSA on primary androgen deprivation therapy is the leading indicator of progression to castration-resistant disease, but there's quite a spectrum of what that means with different patients. We consider the time from initiation of ADT [androgen deprivation therapy] to progression as an important indicator about the necessity of adding or intensifying systemic treatment. We consider the rate of PSA rise, or so-called PSA doubling time, in subsequent decisions about adding systemic treatment. PSA doubling time is an established part of decision-making in non-metastatic castration-resistant prostate cancer, where the 3 pivotal studies in that disease state included patients who are at higher risk for progression based on a PSA doubling time of less than 10 months.
Transcript edited for clarity.
Case: A 82-Year-Old Man with Metastatic Castration-Resistant Prostate Cancer