Observation is safe, cost-saving in low-risk prostate cancer, study suggests

Writing in the June 18 issue of the Annals of Internal Medicine, the authors said their statistical models showed that "observation is a reasonable and, in some situations, cost-saving alternative to initial treatment" for the estimated 70 percent of men whose cancer is classified as low-risk at diagnosis.

The researchers, led by Julia Hayes, MD, a medical oncologist in the Lank Center for Genitourinary Oncology at Dana-Farber, said their findings support observation -- active surveillance and watchful waiting -- as a reasonable and underused option for men with low-risk disease.

"About 70 percent of men in this country have low-risk prostate cancer, and it's estimated that 60 percent of them are treated unnecessarily" with various forms of radiation or having the disease removed with radical prostatectomy surgery, said Hayes, who is also a senior scientist at MGH's Institute for Technology Assessment. A clinical trial called PIVOT reported that such men had about the same small risk of death over a 12-year period whether they underwent radical prostatectomy or simply observation.

Hayes and her co-authors created mathematical models to construct a variety of scenarios, focusing on men ages 65 or 75 at diagnosis, and including estimated costs associated with treatment and different forms of observation.

In active surveillance (AS), patient undergo blood tests for prostate specific antigen (PSA) every three months, rectal examinations every six months, and a prostate gland biopsy at one year and then every three years. If the tests find the cancer is more aggressive than originally thought, the patients begin treatment aimed at curing the disease. "This approach could also be described as deferred treatment," said Hayes.

A patient who chooses watchful waiting (WW) is observed without intensive monitoring and is given palliative treatment when the cancer becomes symptomatic.

Treatments for low-risk prostate cancer include radical prostatectomy, intensity-modulated radiation therapy (IMRT) or brachytherapy (radioactive seed implants.)

The investigators calculated the quality-adjusted life expectancy, or QALE, for the different strategies. (QALE takes into account both the years of life gained and factors that reduce quality of life, such as undergoing invasive tests, the impact of treatment and complications, and disease recurrence.) The researchers also estimated the lifetime costs of each strategy, which ranged from $18,302 for watchful waiting for men aged 75 to $48,699 for a 65-year-old patient treated with IMRT therapy.

The bottom line result was that observation was more effective and in some cases less costly than initial treatment for low-risk prostate cancers. Watchful waiting yielded 11 months additional QALE over brachytherapy -- the most effective treatment -- and 13 months additional QALE over radical prostatectomy, the least effective treatment.

Hayes acknowledged that the study made assumptions based on limited research data on these issues. Nevertheless, "it appears that active surveillance and watchful waiting are safe alternatives to initial treatment for prostate cancer based on these assumptions. But it's important to emphasize that these decisions are very much a matter of individual choice."

Study co-author Philip Kantoff, MD, director of the Lank Center for Genitourinary Oncology at Dana-Farber and a professor of medicine at Harvard Medical School, commented: "This study delineates the cost benefit of active surveillance as well as watchful waiting -- the less aggressive assessment strategy.

"A previous study by Dr. Hayes and colleagues demonstrated that active surveillance is a reasonable option for men with low-risk disease and associated with a better quality of life," Kantoff added. "As non-treatment becomes a more accepted option for these patients, selecting those who require less aggressive assessment including biopsy will become important."

The study's senior author is Pamela McMahon, PhD, at MGH's Institute for Technology Assessment. Others include Daniel Ollendorf, MPH, and Steven Pearson, MD, MSc, of the Institute for Clinical and Economic Review; Michael Barry, MD, of MGH; and Pablo Lee, BS, of MGH's Institute for Technology Assessment.