Men with multiple health problems and a limited life expectancy, and those who would not opt for treatment if a cancer is detected, should not be screened, the task force maintained. And, it added, men aged 70 or older should be told that the potential harms of screening could outweigh the benefits.
That said, there are possible exceptions that could tip the scale in favor of screening. PSA screening is a potential benefit for younger men with a strong family history of prostate or related cancers, men who carry a BRCA1 or BRCA2 mutation, and African-American men, who are more likely than others to develop an aggressive prostate cancer. For them, screening is best started at age 40 or 45.
Among older men, screening can be beneficial to those 70 or over who are very healthy and expected to live another 10 years or longer. Dr. H. Ballentine Carter, urologist at Johns Hopkins Hospital, noted in an editorial in JAMA that “older age is associated with more aggressive prostate cancer; thus, a very healthy older man with the prospects of extended life might benefit from PSA testing.
“Nevertheless,” he added, “routine screening of average risk men 70 years and older should be rare, because they are more likely than younger men to experience the harms of screening, diagnosis and treatment.”
Complicating matters is the fact that circumstances other than cancer can result in an elevated PSA reading. Among them are recent sexual activity, vigorous physical activity, bicycling, benign prostatic enlargement, and inflammation of the prostate. Thus, the test is usually repeated some weeks later before further action is taken.
There are also men in whom the PSA level rises inexplicably and remains elevated despite a repeated inability to find any sign of cancer in their prostates.
In the most definitive study done to date to assess the value of PSA screening, the European Randomized Study of Screening for Prostate Cancer concluded that 781 men aged 55 to 69 when they enrolled would have to be screened to prevent one man from dying of prostate cancer after 13 years. In this study, approximately one man in six who were screened was falsely identified as possibly having prostate cancer, and two-thirds of positive PSA results in the first round of screening were false-positives.