Simulation model suggests active surveillance offers greatest quality-adjusted life expectancy

Active surveillance was associated with the greatest quality-adjusted life expectancy (QALE) in men over the age of 65, a simulation model comparing treatments for prostate cancer predicted.

To examine the value of active surveillance compared with initial treatment, researchers used a simulation model of hypothetical cohorts of 65-year-old men newly diagnosed with clinically localized, low-risk prostate cancer, defined as prostate-specific antigen level <10 ng/mL, stage ≤T2a disease, and Gleason score ≤6. Results appeared in the Dec. 1 issue of the Journal of the American Medical Society.

The model projected outcomes of treating the hypothetical men in various ways. The first involved active surveillance, defined as closely monitoring newly diagnosed patients with serial prostate-specific antigen measurements, digital rectal examinations and biopsies, with treatment at disease progression or patient choice. The second involved treatment at diagnosis with brachytherapy, intensity-modulated radiation therapy or radical prostatectomy. Probabilities and utilities were derived from previous studies and literature review. The relative risk of prostate cancer-specific death for initial treatment vs. active surveillance was assumed to be 0.83. Men incurred short- and long-term adverse effects of treatment.

Active surveillance was associated with the greatest QALE (11.07 quality-adjusted life-years [QALYs]), followed by brachytherapy (10.57 QALYs), radiation (10.51 QALYs), and prostatectomy (10.23 QALYs). When compared, surveillance was associated with 6.0 more months of QALE than brachytherapy, which itself provided 4.1 more months of QALE than prostatectomy.

Researchers also conducted a threshold analysis to identify how much greater the risk of death from prostate cancer would have to be for the surveillance and treatment to be associated with equal QALE. They found that 15% of men undergoing surveillance would have to die of prostate cancer compared to 9% who underwent treatment, a lifetime relative risk of death of 0.6 for treatment compared to surveillance.

"Even if choosing active surveillance places men at a substantially higher risk of dying of prostate cancer or the risk of progressive disease on active surveillance is doubled, active surveillance is associated with higher QALE," the authors wrote.

Limitations include that the model applies only to men age 65 or more, and doesn't consider comorbidities common in older men. This study also includes the limitations of the research upon which model inputs were based. Also, decisions must still be tailored to individuals, and models should be developed to account for such variables, the authors concluded.