Compared with immediate radical prostatectomy, watchful waiting, also known as active surveillance, is likely to reduce disease-specific survival only very modestly among men diagnosed with low-risk prostate cancer while potentially leading to significant benefits in terms of quality of life (QOL).
This is the conclusion reached by biostatistician Ruth Etzioni, PhD, of the Public Health Sciences Division at Fred Hutchinson Cancer Research Center in Seattle, Washington, and codevelopers of a simulation model designed to estimate prostate cancer mortality among men who undergo active surveillance compared with those who undergo immediate radical prostatectomy (Clin Cancer Res. 2012;18:5471-5478). The National Institutes of Health supports active surveillance as a viable option for men diagnosed with low-risk prostate cancer, but this approach has little data to recommend it due to the length of time required to measure its effect on prostate cancer mortality.
The new simulation model combined information on the following:
- time from prostate cancer diagnosis to treatment in 769 men under active surveillance and associated disease progression
- time from radical prostatectomy to recurrence in 3,470 men diagnosed with low-risk prostate cancer (T-stage of T2a or less)
- time from recurrence to prostate cancer–related death from low-risk disease in 963 men whose disease recurred after radical prostatectomy.
With results based on a hypothetical cohort of men aged 40 to 90 years with low-risk prostate cancer, a Gleason score no higher than 6, and a prostate-specific antigen (PSA) level of no more than 10 ng/mL, the model projected that 2.8% of men on active surveillance would die of their disease in 20 years, compared with 1.6% of men undergoing immediate radical prostatectomy. The average projected increase in life expectancy associated with immediate radical prostatectomy was 1.8 months. The model also projected that on average, men on active surveillance would remain free of treatment for an additional 6.4 years relative to men who underwent immediate treatment.
“Although this is not a new result, it is confirmation of what we expected and it substantiates data from previous studies looking at watchful waiting,” commented Etzioni in a statement accompanying the release of her team’s findings. “Very few men with low-risk disease die from prostate cancer regardless, and the difference between treatments appears to be very modest.”
Etzioni did acknowledge that while the 6-year treatment-free interval means men who choose active surveillance will not have to endure treatment side effects during that time, such as impotence or incontinence, it is not clear whether that benefit is overshadowed by anxiety or the need for repeat biopsies.