SAN FRANCISCO—Most older men with early-stage prostate cancer will not require treatment or will die of other causes before their cancer progresses significantly, according to a retrospective study of 9,018 men from the SEER database. The men had been diagnosed with stage I-II disease between 1992 and 2002 and did not receive local therapy initially or hormonal therapy within 6 months of diagnosis.
“Most prostate cancers today are identified through PSA testing, but most of the data we have on the natural history of the disease are from the pre-PSA era. So there is a big knowledge gap. The objective of our study is to bridge this knowledge gap by providing data on screen-detected cancer,” lead author Grace Lu-Yao, PhD, cancer epidemiologist at The Cancer Institute of New Jersey, said at the 2008 GU Cancers Symposium (abstract 10).
She also noted that the current study had a much older population than prior studies of the natural history of prostate cancer. More than 5,000 of the men were age 75 or older (median age, 77).
At 10 years, the risk of dying of prostate cancer ranged from about 6% for men age 66-74 years, to 12% for those age 85 or over. About two-thirds of the men died of other causes or did not have cancer complications requiring surgery or radiation therapy. Less than 3% in all age groups were alive with cancer complications.
Of the 2,675 men who did have some treatment, the median time between diagnosis and the start of cancer therapy was 10.6 years.
As expected, men with less aggressive disease did better than those with high-grade disease. After 10 years, 3% to7% of those with low- or moderate-grade disease had died of prostate cancer, compared with 23% with high-grade cancers.
Dr Lu-Yao noted that the clinical outcomes of this study population were substantially more favorable than those observed in previous studies, perhaps because the use of PSA testing has resulted in earlier detection.
She concluded that conservative management may be reasonable for elderly men with lower-risk localized prostate cancer.
“However,” Dr. Lu-Yao said, “for a more definitive answer, it is very important to support prospective trials such as the START trial (Study of Active Surveillance Therapy Against Radical Treatment).”