Screening guidelines for prostate cancer are on target

A study of more than 12,000 men who had been screened annually for prostate cancer suggests that current guidelines help catch the majority of potentially harmful cancers at early, more treatable stages.

Researchers reviewed follow-up data from 12,453 men between ages 50 and 60 who had been screened between 1991 and 2000. Suspicious results had led to ultrasound-guided biopsy of the prostate gland for 1,571 participants. Of them, 165 were diagnosed with prostate cancer, and about 85 percent of the tumors were considered potentially harmful.

"The take-home message is that early screening catches most prostate cancers at a curable stage," said Robert L. Grubb, M.D., a study leader and resident in urology at the School of Medicine. He presented the findings April 30 at the annual meeting of the American Urological Association (AUA) in Atlanta. Team leader William J. Catalona, M.D., professor of urologic surgery, also discussed the findings at an AUA media briefing May 2.

Many doctors have used a digital rectal exam and a blood test since the early 1990s to evaluate prostate-cancer risk. The blood test measures the circulating level of a protein called prostate specific antigen (PSA), which can rise in the blood when the cancer is present.

Guidelines from the AUA and the American Cancer Society recommend that physicians discuss annual screening for prostate cancer with men 50 and older. For men at higher risk, such as African Americans and those with a family history of cancer, earlier screening has been suggested.

However, some doctors have been reluctant to recommend the PSA blood test out of concern that it might lead to unnecessary treatment while doing little to reduce cancer deaths. Catalona and his colleagues evaluated the cancer prognosis of the 165 men to help address the effectiveness of the screening guidelines.

All 165 men had prostate biopsies to verify the presence of cancer after a digital rectal exam or PSA blood test raised concerns. The majority then had the prostate removed surgically (prostatectomy), though 14 chose radiation therapy and four opted to wait and see if their cancer progressed. Among the 143 men who chose prostatectomy, eight had tumors likely to be harmless. However, five others had rapidly progressing tumors, and the remainder had tumors considered suspect. Among them, though, 119 of the cancers were still confined to the prostate, where current treatments can reduce the risk of cancer return 90 percent of the time.

"We're catching more than 85 percent of the cancers within the prostate using current guidelines," Catalona said.

Results from two other recent studies discussed at the May 2 media briefing support the conclusion that early testing helps reduce prostate cancer deaths. One study published by researchers at the National Cancer Institute found that mortality rates among white and black Americans dropped by 16 percent and 11 percent, respectively, during the 1990s. Another detected a 42-percent drop in the expected 1998 prostate-cancer death rate in the Austrian state of Tyrol. This drop occurred after two-thirds of Tyrolean men between 45 and 75 were screened as part of a free program begun in 1993.

Because treatments for prostate cancer can cause side effects, the University researchers also evaluated difficulties with urination, sexual function and other complications among the 165 men who had cancer. Eighty-three of the 99 men who reported on their ability to control urination were problem-free 18 months or more after treatment. However, 58 of 92 men reported difficulty with sexual intercourse. All but four of these had undergone prostatectomy.

Catalona noted that the prostatectomies were performed in different clinical settings by about a dozen surgeons who might have had varying levels of experience performing the surgeries. In addition, previous studies have indicated that most men are satisfied with their prostate cancer treatment despite any resulting side effects.

"As is the case with most cancers, early treatment produces excellent results in patients with prostate cancer," Catalona said. "The five-year survival rates of men treated for early prostate cancer are nearly 100 percent."