PSA testing helps prevent prostate cancer deaths

A prostate specific antigen (PSA)-based screening is effective in significantly lowering the risk of death from prostate cancer (PC), reports a study. However, nonattendance, initiation after age 60 years, and discontinuation at age 70 years appear to increase such risk.

“Increasing the adherence to the program, starting before age 60, and not stopping at age 70 for all men may further improve the efficacy [of] PC screening but should be balanced by the risk of overdiagnosis,” the researchers said.

A total of 20,000 men born 1930‒1944 were randomly extracted from the Swedish population register and randomized into either a screening group (SG) or a control group (CG) in December 1994. Men in the SG were repeatedly invited for a biennial PSA testing up to an average of 69 years. PC incidence and mortality (intention-to-screen principle) were the primary endpoints.

PC was diagnosed in 1,528 men in the SG and 1,124 in the CG after 22 years. Overall, 112 PC deaths were recorded in the SG and 158 in the CG. [J Urol 2022;208:292-300]

The SG had a PC incidence rate ratio (RR) of 1.42 (95 percent confidence interval [CI], 1.31‒1.53) and a PC mortality RR of 0.71 (95 percent CI, 0.55‒0.91) relative to the CG. The cumulative PC mortality rate for 22 years was 1.55 percent (95 percent CI, 1.29‒1.86) in the SG and 2.13 percent (95 percent CI, 1.82‒2.49) in the CG.

Using the Cuzick method, correction for nonattendance generated a PC mortality RR of 0.59 (95 percent CI, 0.43‒0.80). The number needed to invite and to diagnose stood at 221 and nine, respectively.

Of note, men who did not undergo testing, those who started the program after age 60 years, and those with >10 years of follow-up after screening termination had an increased PC death risk.

“PSA-based screening substantially decreases PC mortality. However, not attending, starting after age 60, and stopping at age 70 seem to be major pitfalls regarding PC death risk,” the researchers said.

Screening initiation

The ideal age for starting PC screening remains to be evaluated, according to the researchers. However, earlier screening does not appear to result in a significantly higher risk of over diagnosis. [J Urol 2016;195:1390-1396]

Moreover, men who did not attend screening had twice the mortality rate as those who attended (2.0 percent vs 0.9 percent).

“As these men also have a higher overall mortality, their ‘true’ RR will be even higher,” the researchers said. [Eur Urol 2013;64:703-709]

“On the other hand, early deaths prevent potential later attendance—maybe some men were in fact ‘potential attenders’ had they lived longer. Hence, an immortal time bias exists, which makes calculations about nonattenders’ ‘true’ RR difficult,” they added.

More accurate assessment of whether the decision to decline screening participation is a well-informed one or based on other factors is warranted, according to the researchers.

“A man’s choice should always be respected, yet it is important to identify which factors play major roles in the decision to attend or not,” they said.