For men over age 65, doing nothing to treat localized, nonaggressive prostate cancer may be the best policy, according to major new research.
Survival rates have improved to 94 percent in such cases, even with no surgery, radiation or hormone therapy.
The finding may lead to a reassessment of the treatment of localized prostate cancer in older men, as patients and doctors find reassurance that conservative management or “watchful waiting” does not result in more deaths.
The study, by researchers from the Cancer Institute of New Jersey in New Brunswick, appeared Wednesday in the Journal of the American Medical Association.
It found that men older than 65 diagnosed since 1992 with mild or moderately aggressive prostate cancer had only a 2 percent to 6 percent chance of dying from the cancer, compared with death rates of 15 percent to 23 percent in the 1970s and 1980s without treatment.
The difference may be due to earlier diagnosis, over-diagnosis as a result of PSA testing or advances in medical care, the study said.
The PSA test, or blood test for prostate-specific antigen, detects prostate cancer six to 13 years before it is found clinically.
“Outcomes following conservative management are now significantly better than those reported in previous eras,” the study said. “Physicians and their patients may need to reconsider this management option.”
Until now, only 10 percent of men over 65 have followed the course of conservative management, despite side effects from treatment that can include impotence and incontinence.
Men diagnosed with prostate cancer face a bewildering decision about treatment options that include surgical removal of the prostate, radiation – either from an external beam or internal implants of radioactive seeds – and hormone therapy to suppress androgens, which stimulate the growth of prostate cancer cells.
“For the majority of patients, their cancer is not that aggressive. They need to balance and weigh the side effects,” said Grace Lu-Yao, a cancer epidemiologist at the Cancer Institute of New Jersey and the lead author of the study.
“A lot of men over 75 have radiation, which has a lot of side effects,” she said. “For that age group, watchful waiting or conservative management is a reasonable decision.”
The results of the study do not apply to men younger than 65, or to those with more aggressive types of prostate cancer, who should be treated.
Prostate cancer strikes 1 in 6 men over the course of a lifetime and is the second-leading cause of cancer death in men. About 192,000 cases nationwide are diagnosed annually.
“In the United States, we have the ability to make the diagnosis earlier and earlier,” Lu-Yao said. “But once we find it, we don’t have the ability to tell which patients will benefit” from the various treatment options available.
The study, based on national data from Medicare and the Surveillance, Epidemiology and End Results cancer registries, is especially important for men older than 75, who have been underrepresented in comparative studies of treatment options.
More than 10,000 patients in that age group were included, Lu-Yao said. The average age at diagnosis for the men treated conservatively was 78.
For men ages 65 to 75 with localized cancer, the study found, the risk of dying from their prostate cancer was 2 percent to 6 percent if the cancer grade was mildly to moderately aggressive, or “moderately differentiated,” and 25 percent to 38 percent if it was aggressive, or “poorly differentiated.”
(Moderately differentiated is represented by a Gleason Score of 5 to 7, and poorly differentiated by a score of 8 to 10, according to the researchers.)
“The key words here are that this study looked at men aged 65 and older,” said Dr. Ihor Sawczuk, chairman of urology and chief of urologic oncology at Hackensack University Medical Center. “If you’re younger, you can’t base your choices on this paper.”
For older patients, he said, the study provided two important pieces of information: If the cancer cells are moderately or well-differentiated, then conservative management is not a bad option. However, if the cancer is poorly differentiated, then the patient should be treated.
A separate study also published Wednesday, in the Journal of the National Cancer Institute by Lu-Yao and a team of Cancer Institute of New Jersey researchers, found that prostate cancer is being diagnosed at an earlier stage, and among younger patients, in 2004-05 as compared with 1988-89.
The age at diagnosis dropped five years, from 72 to 67 years old, and 94 percent of newly diagnosed patients in 2004 and 2005 had localized, early-stage prostate cancer. In addition, the disparity between blacks and whites has narrowed.
Previous studies have shown that African-American men were more likely to be diagnosed at a more advanced stage of the disease.
This study found that the incidence rate for advanced-stage cancer at diagnosis fell from 90.9 per 100,000 positive cases among African-Americans to 13.3; and from 52.7 per 100,000 positive cases among Caucasians to 7.9.
The PSA test became available in 1988 and was in wide use by the early 1990s. Recommendations for its use have been controversial, because diagnosis may lead to additional invasive tests and treatment – with related side effects – that are of little benefit to the patient.
Currently, the American Urologic Association recommends that men in their 40s have a PSA test, to set a baseline for future comparisons, and be screened periodically after that if they choose.
A combination of both a PSA test and a digital rectal exam should be used for prostate cancer screening. Screening is discouraged in men with a life expectancy of less than 10 years.
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