AS feasible for favorable-risk prostate cancer patients
MedWire News: Active surveillance (AS) is a feasible treatment option for men with favorable-risk prostate cancer, and for those who are over 70 years old with intermediate-risk disease, say Canadian researchers.
In a study of 450 men on AS protocols for low- or intermediate-risk prostate cancer, patients were much more likely to die from non-prostate cancer-related causes than from their cancer.
“This strategy provides the benefit of an individualized approach on the basis of the demonstrated risk for clinical or biochemical progression with time,” say Lawrence Klotz and team, from the University of Toronto in Ontario.
The study also highlights the need to improve identification of patients who may “harbor more aggressive disease despite favorable clinical parameters at diagnosis,” suggest the researchers in the Journal of Clinical Oncology.
The median follow-up among the cohort was 6.8 years, during which time the overall survival was 78.6%. Changes to patient’s prostate-specific antigen levels were monitored and biopsies were taken every 6 to 12 months after initial biopsy at diagnosis. The average age of the group was 70.3 years.
The men’s PSA levels and biopsy results were used as markers for disease reclassification during the surveillance period. A PSA doubling time of less than 3 years or a biopsy graduation to Gleason score 4+3 disease or greater was classified as high-risk disease, and definitive therapy was offered to 30% of the cohort on this basis.
Of the 117 reclassified, high-risk patients who received treatment, 50.4% experienced PSA failure (PSA greater than 0.2 ng/ml for patients who underwent surgery, and PSA nadir plus 2 ng/ml for patients who received radiation). These patients represented just 13% of the entire cohort.
Of the intermediate-risk patients (PSA above 15 ng/ml, Gleason score 7, stage T3 disease), only one who was treated after more than 2 years of observation went on to develop metastatic disease and die from prostate cancer. There were just five prostate cancer-related mortalities in the entire cohort.
The overall 10-year cancer-specific survival rate among the cohort was 97.2%. Thus, patients were 18.6 times more likely to die from a non-cancer-related cause than from prostate cancer.
Although the researchers acknowledge that over time the rate of prostate cancer-related deaths may increase, they believe that “the ratio of other-cause mortality to prostate cancer mortality is likely to remain stable.”
The researchers conclude: “In a screened population, even intermediate-risk prostate cancer in men older than 70 years may present a relatively low risk for prostate cancer mortality.”
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By Sarah Guy