Contrary to common belief, men age 75 and older are diagnosed with late-stage and more aggressive prostate cancer and thus die from the disease more often than younger men, according to a University of Rochester analysis published online this week by the journal, Cancer.
The study is particularly relevant in light of the recent controversy about prostate cancer screening. Earlier this month a government health panel said that healthy men age 50 and older should no longer be routinely tested for prostate cancer because the screening test in its current form does not save lives and sometimes leads to needless suffering and overtreatment. Patient advocates and many clinicians disagreed with the finding.
Although the Rochester study does not address screening directly it does raise questions about the benefits of earlier detection among the elderly.
“Especially for older people, the belief is that if they are diagnosed with prostate cancer it will grow slowly and they will die of something else,” said lead author Guan Wu, M.D., Ph.D., assistant professor of Urology and of Pathology and Laboratory Medicine at the University of Rochester Medical Center.
“We hope our study will raise awareness of the fact that older men are actually dying at high rates from prostate cancer,” he said. “With an aging population it is important to understand this, as doctors and patients will be embarking on more discussions about the pros and cons of treatment.”
Wu and colleagues studied the largest national cohort of cancer patients, called the Surveillance, Epidemiology, and End Results (SEER) database. They analyzed 464,918 records of men diagnosed with prostate cancer between 1998 and 2007, known as the “PSA era” because of a strong inclination to recommend the PSA test during that time.
(The prostate-specific antigen or PSA is a protein produced by the prostate gland, which can be measured in the blood. An elevated PSA is associated with cancer and other noncancerous prostate conditions.)
The analysis showed that when age groups are broken down into smaller sections, men 75 or older represented only 16 percent of the male population above age 50 and 26 percent of all cases of prostate cancer -- but 48 percent of cases of metastatic disease at diagnosis and 53 percent of all deaths. In general, higher grade cancer seemed to increase with age, the study said.
Researchers were looking for associations between age, metastasis and death because in clinical practice, Wu said, several URMC urologists observed that many otherwise healthy older men were presenting with very advanced disease at diagnosis, and reporting that they had never had a PSA test.
Indeed, older men have largely been excluded from prior clinical trials of the benefits of early detection, the study said. This is based on the idea that older men wouldn’t benefit from early detection because of a shorter remaining life expectancy.
But Wu and colleagues contend that overall health, more than age, impacts life expectancy following a cancer diagnosis, and that more studies are needed to identify ways to manage the disease in older patients.
“Due to a lot of natural variation in the biology of prostate cancer,” Wu said, “the URMC study should stimulate the need to develop an algorithm to identify healthy, elderly men who might benefit from an earlier diagnosis.”