Most men who choose to have the blood test for early detection of prostate cancer don’t need it every year, according to a large government study.
A preliminary analysis of almost 30,000 patients aged 55 to 74 indicates that most men who undergo the prostate-specific antigen test have initial readings so low that checking every two years, or even every five years, is enough to find the cancer in time.
Scientists still can’t tell, however, whether the PSA test prevents deaths from the common cancer.
An ongoing study sponsored by the National Cancer Institute is designed to find out whether screening for prostate, lung, colorectal and ovarian cancer saves lives. The answer likely will take several more years to determine.
Regarding colon cancer, doctors generally recommend further testing if a man’s PSA level rises above 4 nanograms per milliliter of blood.
Of the men who scored between 0 and 1 on their first screening test, researchers found, 98.7 percent continued to have PSA levels below 4 in the next four years. That suggests those men could wait five years before their next test.
Of those with readings between 1 and 2 on the first screening, 98.8 percent had readings below 4 the following year. They could wait two years before going back for another test.
Those with scores between 2 and 4 had much higher odds of having an elevated PSA level within a year and should, therefore, be screened annually.
PSA tests have become an annual ritual for millions of men over 50. But there are no clear guidelines on screening.
Many medical groups suggest each patient should decide for himself, in consultation with his doctor.
One downside of screening is the risk of a false positive test that shows something suspicious that turns out not to be cancer. Another downside is overdiagnosis–the risk of being diagnosed with something that looks like cancer under the microscope, and, therefore, has to be treated like prostate cancer, even though it doesn’t behave like cancer and will never become life-threatening.
The preliminary results of the prostate cancer trial were presented Monday in Orlando at the annual meeting of the American Society for Clinical Oncology.
Also at the meeting, evidence was presented that women with mutations in certain genes called BRCA1 and BRCA2 can significantly reduce their risk of breast and ovarian cancers by having their ovaries removed.
