The Medical Minute: Challenges from prostate cancer

By John Messmer, M.D.
Penn State Milton S. Hershey Medical Center

This year, Men's Health Week brings controversy about a problem we thought we were making progress in understanding and treating. It used to be a no-brainer: screen men annually for prostate cancer since early detection leads to cures and better health. Turns out, it's not so simple.

After skin cancer, prostate cancer is the most commonly diagnosed cancer in men as a result of widespread screening with the prostate specific antigen (PSA) blood test. Men with a family history of the disease and African-American men are at increased risk. The chance of having prostate cancer diagnosed increases with age from less than 1 in 10,000 under age 40 to 15 in 100 by age 70. The figures are misleading, however, as more than half the men over age 75 likely have latent tumors in their prostates, but most will never be diagnosed.

Several genes have been identified as possible contributors to disease development and diet and ethnicity appear to play a role in causation. Japanese men in the United States have a higher risk than Japanese men in Japan but lower than white American men. Black men have higher risk than white men, but Hispanic men have lower risk than non-Hispanic Caucasians. High fat diet may contribute, but trace elements and vitamins are being explored for their part in the disease. Prostate cancer does not appear to be related to prostate enlargement, a common occurrence in older men, nor is there any association with vasectomy or frequency of intercourse.

Since the risk increases with age, it would seem logical to begin screening for prostate cancer at some time when the rate of the disease increases, for example, age 50. The problem is that when the results of early detection and treatment are examined, it may not add years to life and might actually make the years after treatment worse than they would have been without treatment.

We used to think that a low PSA meant a low risk of cancer, but a recent study in the Journal of the American Medical Association showed that aggressive prostate cancers were found in men with lower PSA levels. Another study looked at men under age 40 who died accidental deaths and found prostate cancer present in up to 30 percent of them. These findings further complicate the ability of doctors to make a general recommendation for all men in regard to prostate screening. In fact, the U.S. Preventive Health Services, the American Cancer Society and the American Urology Association all have stopped recommending universal annual prostate cancer screening and now recommend only that screening be offered along with an explanation of the potential risks and benefits of such screening.

So what's a fellow to do? If his father or brother had prostate cancer, he should be offered screening earlier than the earliest age it was detected in his family. Black men should be offered screening earlier, probably in their forties. Symptoms such as difficulty urinating, a burning sensation and blood in the urine should probably not lead to screening as prostate cancer is not associated with these symptoms and the problems that are related to them might cause a falsely elevated PSA. White men over 50 should be considered for screening.

Screening should probably consist of a digital rectal exam, as lumps in the prostate are a reason for urology referral. If PSA is done, prostate cancer is very unlikely if the result is less than 1. In men with normal prostate exams, interpreting the PSA is complicated.

For PSA between 1 and 2.5, it is not completely clear. Although prostate cancer could be present, whether to have further evaluation depends on the prostate examination, the man's age and ethnicity, his general health and family history. Men over 75 with normal prostates generally can be reassured.

If the PSA is between 2.5 and 4 for the first time or if it has been steadily rising, further evaluation might be reasonable for younger men, particularly black men or those with a family history of prostate cancer. Men over 75 may have prostate cancer, but it tends to be slower growing. If a man over 75 is in very good health and can expect to live 15 more years, urology referral should be considered. Diagnosis of a low-grade cancer on biopsy might be best managed by observation since treatment might be worse than the disease.

For a PSA between 4 and 10, further evaluation is to be considered. There can be many other reasons for a higher PSA, such as, a large prostate or recent trauma or inflammation. If biopsy is negative and subsequent PSA determinations do not rise, the man can be reasonably relaxed about his risk of cancer.

PSA over 10 is more likely to be due to cancer but the man's age and general health must be considered in deciding whether to biopsy or to treat if cancer is found.

Much research is underway to see if other tests can help pinpoint the individual risk or whether certain medications or dietary interventions will help, but no conclusions have been reached so far. Since doctors do not have enough scientific evidence to give a general recommendation, the best thing for a man to do is to visit his family physician or general internist for a discussion of risk tailored to his own background, and then make an informed decision about screening for prostate cancer in collaboration with his doctor.