If the number of men with newly diagnosed prostate cancer who opted for watchful waiting increased from 10 percent to 50 percent, the resulting savings would surpass $1 billion, researchers estimated in a study published June 18 in Annals of Internal Medicine. The authors noted that new molecular imaging techniques could improve classification of low-risk candidates and set the stage for a more conservative approach than the active surveillance model.

Nearly 70 percent of men with newly diagnosed prostate cancer have low-risk disease (stage ≤T2a, PSA level < 10 ug/L, Gleason score ≤3 + 3). Yet, more than 90 percent of these men undergo treatment with radical prostatectomy, external beam radiation or brachytherapy. Research suggests up to 60 percent do not need the treatment. The high incidence of long-term adverse effects adds to the costs.

Watchful waiting and active surveillance offer alternate approaches. Active surveillance entails serial PSA testing, digital rectal exams, biopsies and treatment as needed. Watchful waiting entails monitoring and palliative treatment when the disease becomes symptomatic.

Julia H. Hayes, MD, from Dana-Farber Cancer Institute in Boston, and colleagues devised a decision analysis model to determine the costs and benefits of observation versus initial treatment for men ages 65 years and 75 years with low-risk, clinically localized prostate cancer undergoing intensity-modulated radiation therapy (IMRT), brachytherapy, radical prostatectomy, active surveillance or watchful waiting.

Costs were based in 2012 dollars and included prostate cancer treatment costs and treatment of erectile dysfunction, urinary obstructive symptoms, short- and long-term adverse side effects and patient time costs.

The model showed lifetime risk for death from prostate cancer was 4.8 percent for men on active surveillance, 6 percent for men on watchful waiting and 8.9 percent for men treated initially, according to Hayes et al.  Life expectancy was 81.6 years for men on active surveillance, 81.4 years for men on watchful waiting and 81.2 years for men treated initially.

Watchful waiting delivered quality-adjusted life expectancy (QALE) at the lowest cost among men aged 65 years, and provided two additional months of QALE for $15,374 less than active surveillance. The model showed similar results for men aged 75 years.

Among treatment strategies, radical prostatectomy cost $12,199 for men aged 65 years and IMRT cost $25,569.

All analyses placed watchful waiting as the least expensive alternative. “For AS [active surveillance] to be equal to WW [watchful waiting] in cost, we had to set the cost of treatment equal to that of BT [brachytherapy] , the least expensive treatment; reduce costs of surveillance and treating short- and long-term adverse effects of treatment by 50%; and decrease the probability of being treated by 40%.”

Hayes et al attributed the high cost of active surveillance to the cost of treatment and curative intent. The researchers concluded, “Despite the considerable uncertainty surrounding inputs in this model and the limitations of the study, one may conclude that observation is a reasonable, and in some situations, cost-saving alternative to initial treatment.”

Looking forward, Hayes and colleagues suggested that employing emerging molecular and imaging tools to classify men and study varying levels of surveillance “could provide further support for WW and AS as reasonable and underused options for men with prostate cancer.”