Active Surveillance of Prostate Cancer: Evaluating Long-Term Outcomes

Announcer:
You’re listening to On the Frontlines of Prostate Cancer on ReachMD. On this episode, we’ll hear from Dr. Lisa Newcomb, who’s the Deputy Director of the Canary Prostate Active Surveillance Study at the University of Washington and Fred Hutchinson Cancer Center in Seattle. She’ll be discussing her research on the long-term outcomes for patients with prostate cancer who are managed with protocol-directed active surveillance. Here’s Dr. Newcomb now.

Dr. Newcomb:
Well, thank you for the opportunity to discuss our publication about long-term oncologic outcomes in patients using active surveillance to manage their prostate cancer. So the overarching goal of our study was to report these outcomes to help achieve a better understanding of how to optimally avoid overtreatment of cancers that will never cause harm if they’re left untreated while at the same time preventing undertreatment of truly aggressive disease. And so to achieve this goal, we set up a multicenter surveillance study that prospectively accrued and followed patients according to a standardized protocol. The eligibility requirements were deliberately broad so that participants represented everyone who uses active surveillance, and even with these broad eligibility criteria and no exclusion based on Grade Group or PSA, 90 percent of the participants were diagnosed with Grade Group 1 cancer—this is Gleason 3+3 cancer—and the median PSA at diagnosis was 5.2 ng/mL.

So accrual started in 2008 at 10 different sites. Patients who chose to use active surveillance rather than immediate curative treatment were enrolled and followed closely with regular PSA measurements, clinic exams—these were both done every six months—periodic prostate biopsies—by that I mean a year or two apart—and more recently, MRI. If there were signs of progression, treatment was offered. If there were no signs of progression, treatment could be avoided altogether. 

The outcomes that we assessed were both reclassification and treatment rates. We define reclassification as an increase in Gleason Score at a follow-up biopsy. We also assessed cancer recurrence after treatment metastasis, death due to any cause, and death due to prostate cancer. 

So we found that 10 years after diagnosis, half of the participants had received definitive treatment. So the flipside of this is half of the participants have not been treated, saving a lot of comorbidities of treatment. About 45 percent had reclassified at biopsies, and about 15 percent were reclassifications to Grade Group 3 or above, which is a phenotype that we would like to avoid. Less than 2 percent of the participants developed metastatic disease at 10 years, and well less than 1 percent have died of prostate cancer, while in the same time frame, the overall mortality was 5 percent.

And one of the unique and important findings is that we compared outcomes in patients treated following the first surveillance biopsy. This means that they were treated about a year after diagnosis. We compared those two participants treated after multiple follow-up biopsies at a median of about four and a half years after diagnosis. So we found very similar rates of adverse outcomes in these patients, and this suggests that the delay in treatment did not cause harm.

So putting all of this together, these results demonstrate that, in patients using active surveillance for favorable-risk prostate cancer, the rates of adverse outcomes that we don’t ever want to see are very low. They’re not zero, but they’re very low, and our findings really support the use of active surveillance compared with immediate treatment for favorable risk prostate cancer. 

Announcer:
That was Dr. Lisa Newcomb talking about her research, which examined the long-term outcomes associated with protocol-directed active surveillance for prostate cancer patients. To access this and other episodes in our series, visit On the Frontlines of Prostate Cancer on ReachMD.com, where you can Be Part of the Knowledge. Thanks for listening!