May 4, 1999
Web posted at: 1:29 p.m. EDT (1729 GMT)

WASHINGTON (CNN) -- Researchers from Johns Hopkins University have developed a formula to calculate the cancer relapse risk for patients who have undergone prostate removal and still have an elevated prostate-specific antigen (PSA), according to a study in the May 4 Journal of the American Medical Association (JAMA).

PSA, a protein produced by the prostate gland, is used as an indicator of cancer activity. Men without prostates should have no PSA in their blood, unless some prostate cancer cells remain after surgery and are roaming throughout their bodies.

Prostatectomy often cures prostate cancer, but sometimes the cancer does return in other parts of the body. When this happens it is called metastatic and is considered incurable. Once men relapse, the median survival is five years.

A third of men who have cancerous prostates removed have post-surgical blood tests that suggest the cancer is returning. But tumors may not appear for years. According to the study, it can take a median of eight years from the first elevated PSA test after prostate removal to the development of metastatic cancer.

And most of the men in the study did not relapse; 82 percent were cancer-free 15 years after surgery.

The study "provides evidence that a rising PSA level after a surgery is not a death warrant for all patients," said Dr. Howard Scher of Memorial Sloan-Kettering Cancer Center.

Without a predictive formula, doctors have not been able to determine who needed aggressive treatment in response to elevated PSA readings. Men were frightened and confused by an elevated PSA reading.

Dr. Mario Eisenberg and colleagues studied 1,997 men who underwent radical prostatectomy for clinically localized prostate cancer between 1982 and 1997. They found length of life was related to how soon after surgery the PSA was detected, how fast it rose and whether the initial prostate tumors were high- or low-grade. The longer it takes for an abnormal PSA to appear after surgery, the longer the patient will survive.

For example, a 75-year-old man whose PSA was normal until four years after surgery and whose initial tumor was low-grade probably won't relapse for more than 10 years, Eisenberg said. A patient in this situation may choose no treatment, since healthy men of that age have a 10-year life expectancy anyway.

In contrast, men with high-grade tumors who have an elevated PSA reading within two years of surgery are at risk for relapse within eight years and may choose treatment, especially if they're younger.

The Associated Press contributed to this report.