Sept. 16, 2003 -- Men who have survived their first bout with prostate cancer may be able to get an idea about their future within three months after treatment, according to a new testing method.
Researchers found that in patients with localized, non-metastatic prostate cancer, if the patient's PSA (prostate-specific antigen) levels double within three months after prostate cancer surgery or radiation, they may eventually die from a recurrence of the disease or other causes within 10 years.
The researchers say that a recurrence of prostate cancer, as defined by a PSA after surgery or radiation treatment, is an indication of treatment failure, but what is unclear is whether an increase in PSA after treatment for prostate cancer also points to an increase in the death rate from the disease. Not all patients who have recurrences of prostate cancer die of prostate cancer.
"We can say with 98 percent certainty that if a patient's PSA doubles in less than three months, they may succumb to the disease in under ten years. However, the good news is that it appears only a small population of men are included in this category," says Anthony D'Amico, MD, PhD, a radiation oncologist at Brigham and Women's Hospital and Dana-Farber Cancer Institute, in a news release.
Prostate cancer is the second most common cancer among men, and nearly 29,000 men die from the disease each year.
But researchers say it is also one of the few cancers for which there is routine follow-up test, known as a PSA blood test, which can help detect the risk of disease recurrence.
However, they say that until now the degree to which PSA test results might also be an accurate indicator of the risk of death due to prostate cancer has not been evaluated.
PSA Test Reveals Death Risk
The study, published in the Sept. 17 issue of the Journal of the National Cancer Institute, suggests that short-term monitoring of PSA levels may also reveal the long-term risk of death for prostate cancer patients.
Researchers looked at 8,669 men with localized prostate cancer who were treated with surgery or radiation therapy and tracked their PSA levels over a 10-year period.
"We discovered that the speed with which the PSA level grew, specifically how fast it doubled, signaled pending prostate cancer mortality," says D'Amico. "When the PSA doubled in less than three months, the risk of dying from the disease increased 20 times. This meant that the cancer in and of itself was the sole cause of death."
Researchers say the results suggest that patients whose PSA test results show rapidly rising PSA levels should be treated aggressively and given priority for clinical trials to improve their survival chances.
In an editorial that accompanies the study, Howard M. Sandler, of the University of Michigan, and colleagues say that more study is needed before PSA doubling time can be widely used as a new end point to speed clinical trials and determine when more aggressive treatment is needed.
"Caregivers and patients with prostate cancer know intuitively that PSA levels after therapy are telling us something very important about the future course of the patient's prostate cancer," they write. Depending on that patient's previous history, "the tale being told may be somewhat different."
The challenge, they say, will be converting this intuitive sense to a sound statistical definition of use to researchers.