MedWire News: Men with localized prostate cancer may be receiving curative therapy when it is unlikely to be of clinical benefit in terms of their life expectancy and risk for cancer progression, show findings from a US study.
"Treatment can do more harm than good in some instances," said lead author Cary Gross of Yale University School of Medicine, New Haven in a press statement. "Among men who are older and have less aggressive forms of prostate cancer, their cancer is unlikely to progress or cause them harm in their remaining years."
The National Comprehensive Cancer Network practice guidelines in oncology recommend active surveillance as an alternative to curative therapy (radical prostatectomy or radiation therapy) for patients with low-risk tumor characteristics who have a life expectancy of less than 10 years. For patients with intermediate-risk cancers and a life expectancy of 10 years or more, curative therapy is recommended.
However, "it is unclear whether patterns of care correspond to the likelihood of clinical benefit from treatment, as determined by life expectancy and tumor characteristics," write Gross and team in the Archives of Internal Medicine.
Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked database, the researchers identified 39,270 patients who had been diagnosed with localized prostate cancer between 1998 and 2007. They defined low-risk tumors as those with SEER grade 1 or 2 and tumor, nodes, metastasis (TNM) stage T1 or T2a. Moderate risk tumors were defined as those with SEER grade 3 or 4 or TNM stage T2b-T2c.
They then determined annual mortality rates for each age and comorbidity stratum in a sample of patients without a cancer diagnosis and used these rates to estimate life expectancy as a function of noncancer comorbidity. Patients with a life expectancy of less than 5 years, 5 to 10 years, or 10 years or more were classified as having short, intermediate, or long life expectancy, respectively.
The researchers report that, of the prostate cancer patients identified, 64.3% had received curative therapy. Approximately 39.1% of patients with a short life expectancy, 62.8% of those with an intermediate life expectancy, and 75.1% of those with a long life expectancy received the treatment.
Within each tumor-risk category, the use of curative therapy differed according to patients' life expectancy.
Among men with moderate-risk cancer, the use of the therapy significantly increased in those with a short life expectancy, from 38.0% in 1998-1999 to 52.1% in 2006-2007, whereas it decreased slightly in men with a long life expectancy, from 80.7 to 80.0%.
Furthermore, among men with low-risk tumors, the curative therapy rate showed a downward trend in those with a long life expectancy over time whereas it increased for those with short and intermediate life expectancies.
"We were surprised to find that the biggest increase was among men with moderate-risk prostate cancer who had the shortest life expectancy," said Gross.
"While not treating potentially fatal cancer can reflect poor-quality care, aggressive management of disease that is unlikely to progress puts patients at risk for morbidity and increases cost without medical benefits," say the investigators.
Future research should explore how better to incorporate both cancer characteristics and patients' life expectancy into decision-making, they conclude.
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