Optimizing Surveillance Protocols After Focal Therapy for Prostate Cancer

Long-term monitoring after focal cryoablation for prostate cancer requires balancing the detection of recurrent disease against the burden of an invasive procedure. In a recent interview with CancerNetwork®, Herbert Lepor, MD, Martin Spatz Chair of the Department of Urology and director of the Smilow Comprehensive Prostate Cancer Center at NYU Langone Health, detailed his team’s established surveillance protocol, which includes serial prostate-specific antigen (PSA) testing every 6 months alongside targeted MRI scans extending out to 10 years.

While early practice dictated mandatory post-treatment biopsies for all patients, long-term outcome data led to a more refined strategy. For men presenting with stable PSA levels and no MRI suspicion of disease in or out of field, the risk of clinically significant cancer is roughly 10%, often consisting of disease presenting as less than a millimeter in size. Lepor noted that accepting this minimal risk avoids unnecessary protocol biopsies without compromising long-term safety, as serial monitoring ensures that any emerging, clinically significant cancer is captured and managed appropriately over time.

Transcript:

CancerNetwork: Given a 91% negative predictive value but 25% sensitivity of MRI after focal cryoablation, what is your current recommendation for the ideal long-term surveillance protocol, and when should a protocol biopsy be mandated despite a negative MRI?

Lepor: What we do, today, is a PSA test every 6 months, and an MRI at 6 months, 2 years, 3.5 years, 5 years, 7.5 years, and—soon—10 years. When we first started the focal therapy journey, we did not have a good sense of if we were effectively destroying the disease, or whether disease was developing out of field, so we biopsied everybody at 6 months and again at 2 years. What we found is that if the MRI showed no suspicion for recurrence in or out of field, and there was no progressive increase in PSA, the detection of what we call clinically significant cancer—any Gleason pattern 4—was about 10%. When we make decisions about who we biopsy, we realize that if we want to identify every single cancer, we would have to biopsy everybody, so we accept a threshold of what we are willing to miss on a biopsy to avoid over-biopsying.

In this case, we feel that missing 10% of cancers by not biopsying men with a normal, stable PSA fits the way we make decisions about who gets a biopsy to begin with. We will continue to follow these [patients], and in fact, in that 10% of cases where we missed a Gleason pattern 4, it was less than 1 mm, so we will follow that patient. If the disease becomes clinically significant, we will detect it. At this point, we have that surveillance protocol, and we do not biopsy; we feel confident that this is a good balance between detecting recurrent disease and not over-biopsying everybody.