COMMENTARY

Does Prostate Cancer Screening Decrease Mortality?

Gerald Chodak, MD

Disclosures

October 16, 2018

Hello. I'm Dr Gerald Chodak from Medscape. Today's topic is screening for prostate cancer, prompted by a recent report by Alpert,[1] in which more than 400,000 men from the Kaiser Permanente Health System were evaluated for the effect of screening.

This is a retrospective analysis of men who underwent prostate-specific antigen (PSA) testing between 1998 and 2002 and were followed for 12-16 years. The patients were divided by age at screening and by interval of PSA testing. The main findings are as follows: A 64% reduction in cancer mortality and a 24% reduction in overall mortality were detected in men who were screened compared with men who were not screened. There also was no benefit for screening men under age 55, and the optimal interval for achieving a benefit was screening yearly.

I have two reasons for presenting and discussing this paper. The first is that these results are widely different compared with two large, randomized trials that have been reported previously. In the US trial, there was no benefit seen in overall survival or cancer mortality; yet, this study has been criticized because of the high contamination in the control group.[2] Nevertheless, given the magnitude of benefits seen in the Alpert study, there were enough uncontaminated patients in the American trial to be able to detect a difference, if there really was one.

In the European trial, a 21% lower cancer mortality was detected, but there was still no change in overall survival.[3] This study suffers from two critiques. First, the benefit was primarily from the Swedish patients, which represent only 12% of the entire group, and even the Swedish patients did not have a change in overall survival. A second critique of this study is that more men in the control arm were treated conservatively compared with the men who were in the screened arm. This could have certainly introduced a bias in favor of screening.

A second reason for discussing this paper is related to the apparent differences in a randomized trial compared with a retrospective analysis. With such a wide difference in findings, we are forced to conclude that the uncontrolled trial appears to be overstating the magnitude of benefit that can be achieved with screening for prostate cancer. I look forward to your comments.

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