COMMENTARY

Have Relaxed PSA Recs Resulted in Unchecked Prostate Cancer?

Gerald Chodak, MD

Disclosures

September 20, 2018

Hello. I'm Dr Gerald Chodak from Medscape. Today's talk is on the potential consequences of the US Preventive Services Task Force (USPSTF) recommendations against routine screening [for prostate cancer] that occurred in 2012. Critics of that recommendation raised concerns that it would lead to an increase in the proportion of men who had incurable cancer at the time of diagnosis.

Ahlering and colleagues[1] conducted an analysis to try to evaluate this possible concern. They looked at about 20,000 men who had radical prostatectomy at one of nine large-volume centers between 2008 and 2016. Specifically, they were interested in the proportion of men who had Gleason score 8, 9, or 10 disease, seminal vesicle invasion, or lymph node metastases. They divided the patients into two groups: those treated before and those treated after October 2012.

Here are some of their findings. First, there was a significant decrease in the proportion of men with Gleason 3 + 3 disease who had surgery, and at the same time there was an increase in the proportion of men who had Gleason 8, 9, or 10 disease. They reported an increase in the absolute number of men with Gleason 8 to 10 disease.

They also found that the mean age increased from 61 to 62 years and that prostate-specific antigen (PSA) increased from 5.1 to 5.8 ng/mL at the time of diagnosis. And there was a significant decrease in overall surgical volume. Based on these findings, they raised concerns about the recently changed recommendation that men have a discussion about the pros and cons of screening and make a decision.

Before we use this paper, however, there are a number of concerns that question the importance of the findings. First of all, the decrease in the number of men with Gleason 6 cancer having surgery could be due to two things: Genetic/genomic tests had already become available by 2013, and more important, there was a growing use of active surveillance for men with low risk-disease (which includes both Gleason 6 and some Gleason 7s).

Also, the authors said that there was an increase in the absolute number of men with Gleason 8 to 10 disease, yet, their supplementary data showed a decrease in the number of men with Gleason 9 and 10 disease; I could not see the data for Gleason 8. They used propensity matching to account for possible changes in referral patterns as an explanation for their data. However, there are significant weaknesses to that approach and it does not remove the need for a randomized study to avoid potential bias. Another possibility is that more men simply may have chosen to undergo the various forms of radiation therapy instead of undergoing radical prostatectomy.

Last, there was an increase in the proportion of men who had biochemical failure at 1 year after surgery. This could partly be because there was a decreased proportion of men with Gleason 6 disease who underwent surgery. One would expect that proportion to increase. What is unclear from the abstract is whether they did grade-to-grade comparisons. In other words, it would be useful to see whether a different or similar proportion of men with Gleason 8, 9, or 10 disease prior to the date of the recommendation had biochemical recurrence at 1 year. To analyze entire populations together introduces considerable bias.

What does this mean going forward? USPSTF has recommended Level C guidance for screening [men aged 55-69 years],[2] meaning that the pros and cons should be discussed with the patient and then a decision should be made. I think it is very important that doctors not use this paper as a basis for recommending that screening proceed.

I look forward to your comments. Thank you.

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