Surgery to remove small, low-risk prostate cancer tumours can be safely delayed for years without an increased risk of death, according to results from a large long-term study.
With the advent of early screening for prostate cancer in the late 1980s, doctors have been able to detect tumours at much earlier stages, noted Harvard professor Martin Sanda, who co-authored the
research published in the Journal of Clinical Oncology.
But while the so-called prostate-specific antigen (PSA) testing "has enabled us to successfully begin aggressive treatment of high-risk cancers at an earlier stage, it has also resulted in the diagnosis of cancers that are so small they pose no near-term danger and possibly no long-term danger," he said.
Sanda and his team studied the health of 51,529 men since 1986, with participants responding to a health questionnaire every two years. In total, 3,331 of the men reported getting a prostate cancer diagnosis between 1986 and 2007.
Out of this group, 342 men - just over 10% - opted to defer treatment for one year or longer, and 10 to 15 years later, half of the men still had not undergone any treatment. Compared to the patients who opted for aggressive treatment such as surgery or radiotherapy, Sanda's team found that deaths attributed to the cancer "were very low among the men with low-risk tumours".
No statistically significant difference
The research showed only two percent of those who deferred treatment died of the disease - compared with one percent of the men who began treatment immediately following their cancer diagnosis. "This is not a statistically significant difference," Sanda said.
His research team suggested a better approach than broadly encouraging initial treatment, which significantly disrupts a patient's quality of life, would be treatment for high-risk prostate cancers and just initial monitoring for the low-risk tumours.
"This would avoid problems due to treatment of 'overdiagnosed' low-risk cancers, while preserving the life-saving benefits of treating aggressive cancers that have been detected through PSA testing," Sanda said.
Another new study also suggested the largely successful PSA screening method has led to massive overdiagnoses for prostate cancer.
According to research published online in the Journal of the National Cancer Institute, since 1986 an additional 1.3 million men have been diagnosed with prostate cancer who would otherwise have never been diagnosed without the screening, and more than one million have been treated.
Researchers wrote that many of those overdiagnosed patients "are needlessly exposed to the hassle factors of obtaining treatment, the financial implications of the diagnosis, and the anxieties associated with becoming a cancer patient". – (Sapa, September 2009)
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