PSA testing seems to lower long-term risk for prostate cancer metastasis
Posted Oct 28 2010 12:00am
We have previously noted that there is a clear association between early detection and a reduced likelihood of diagnosis with more advanced forms of prostate cancer. Now it seems that early detection actually reduces risk for metastasis too. This is the conclusion of a study by Reddy et al. that will be presented next Monday at the upcoming annual meeting of the American Society for Radiation Oncology (ASTRO) in San Diego. The announcement comes in a media release from ASTRO .
According to the media release, Dr. Reddy said that, “Our study shows that routine screening not only improves the patient’s quality of life by stopping metastatic disease, but it also decreases the burden of care for this advanced disease that must be provided by the health-care system.”
Reddy and his colleagues looked at data from 1,721 prostate cancer patients who were diagnosed between 1986 and 1996 and then given first-line treatment with either radiation therapy or surgery at the Cleveland Clinic. Patients diagnosed and treated in the first part of this study period (1986-92) were diagnosed before the widespread availability of the PSA test (in the period from 1993 to 1996). Patients were also categorized as having high-, intermediate- or low-risk disease to determine which groups may have benefited the most from prostate cancer screening.
The authors then looked at 10-year risk for disease progression, with the following results:
At 10 years of follow-up, 13 percent of the patients had clear evidence of metastatic disease.
Regardless of initial risk classification, men diagnosed as a result of PSA screening were significantly less likely to have metastatic disease at 10 years of follow-up than men diagnosed based on clinical signs and symptoms alone.
Dr. Lionel L. Banez, an assistant professor of urologic surgery at Duke University Medical Center, has said that, “There is compelling evidence that PSA testing saves lives, especially when performed in an optimized strategy. For example, getting an initial PSA measurement at age 40 to properly assess baseline prostate cancer risk has been proven to be quite beneficial.” This viewpoint reflects the current recommendations of the American Urological Association.
However, the role of mass, population-based screening (as opposed to risk-based individual testing) for prostate cancer is highly controversial. While there is no doubt whatsoever that early detection of prostate cancer “saves lives” in otherwise asymptomatic men who are diagnosed with high-risk, localized and even locally advanced forms of prostate cancer, there are major risks associated with widespread annual screening of all men over some specific age. As yet there is no consensus about how to resolve this dichotomy. Even Dr. Banez adds that, “The challenge lies in ensuring that the risks for over-diagnosis and over-treatment, as well as potential decline in quality of life, are minimized or avoided.”