Does Active Surveillance Increase Metastasis Risk for PCa?

Gerald Chodak, MD


June 29, 2017

Hello. I am Dr Gerald Chodak for Medscape. Today I want to talk about some recent new data on active surveillance that was presented at a European meeting.

The Dutch reported their results on about 900 men who were diagnosed during the first and second year of a European screening trial that began in 1993.[1] They now have about 15 years of follow-up data on their cohort, which includes 25% receiving active surveillance, about 35% receiving external radiation, and the remainder receiving radical prostatectomy.

Thus far, they found the following: The men who had active surveillance as their initial therapy had less than a 1% lower metastasis-free survival and less than 1.5% lower prostate cancer-specific survival compared with the men who had radical prostatectomy. Not surprisingly, these differences were not statistically significant.

Conclusions must be made very carefully because these data were not from a randomized trial and, in fact, the data have been compared with those of the ProtecT trial, which found a greater difference between the men who were managed with active surveillance compared with the men who received definitive therapy.

An important difference is that in the ProtecT trial, men were included who had either intermediate- or even high-risk disease in this low-risk category of men who were treated with active surveillance. The groups are not entirely comparable. In fact, today, few people would treat some of those men in the ProtecT trial with active surveillance.

What can we say about these findings? One of the challenges with doing randomized trials is that the statisticians tell us we must analyze the data according to an intention-to-treat analysis. That means that if someone was assigned to active surveillance but ended up getting surgery, they still had to be included in the active surveillance group, so there is always a contamination that occurs. In the ProtecT trial, only 72% of the men followed through with their assigned therapy. This always complicates analyses.

Here, we have data from a nonrandomized trial that at least allows a look at what to expect in a large group of men who were treated with various options. Thus far, with a rather long follow-up, the differences are extremely small. At the least, it means that going forward, patients who were diagnosed with low-risk disease should be made aware of these findings when they are making decisions. It does not mean that you can tell patients that there is no difference between the different arms, but it certainly seems that the risk for men who get active surveillance appears to be extremely low at the 15-year mark.

What is unclear from this analysis is what percentage of the men who started on active surveillance ended up getting definitive therapy. Regardless of what that number is, it does mean that active surveillance is a very reasonable option for men with low-risk disease.

I look forward to your comments. Thank you.


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