Few low-risk prostate cancer patients undergo observation

"There is an increasing concern that the enthusiasm for treatment may exceed the need among these low-risk cases," said the study's senior author, John T. Wei, MD, MS, associate professor of urology at the University of Michigan Medical School, Ann Arbor. "The fact is that the vast majority of prostate cancer patients today are diagnosed in the early stages, and many have low-risk disease."

Previous studies suggest that following men with low-grade cancer may be a reasonable option, particularly given the competing risk of dying from other causes, such as heart disease or stroke. The latest research comparing radical prostatectomy against active surveillance has found that younger prostate cancer patients are the most likely to derive benefit from treatment.

"We defined low risk in this study as men with well differentiated (low-grade) prostate cancer, across all age groups. We then added to the low-risk group men over age 70 who had moderate-grade cancer with Gleason scores 6 and 7," Dr. Wei said.

55% have surgery or RT

Researchers studied 64,112 men diagnosed with early-stage prostate cancer using the Surveillance, Epidemiology and End Results (SEER) registry. They divided the men into high-risk or low-risk categories. Among the 24,835 men with lower-risk cancers, 10% were treated with surgery and 45% with radiation therapy.

"The fact that 55% of these men with low-risk cancer ended up having some form of definitive treatment for the cancer within the first year is a statistic that is novel and worth emphasizing," Dr. Wei said. "Eighty-one percent of these low-risk patients who were treated had radiation therapy, which is an important finding because of the uneven distribution. It should prompt researchers to ask why men are more likely to have radiation therapy since surgery and radiation are seen as equally effective therapies for low-risk disease."

The study results raise a number of important questions, according to Dr. Wei, including: How are treatment decisions being made? Are men being given sufficient evidence-based information regarding their treatment options? Are men uniformly being offered active surveillance when they are in a low-risk group?

Dr. Wei said he was surprised when he and colleagues compared their findings in this study to data from a decade ago. They looked at the same data set, definition, and cohort, and found that the treatment rate was lower 10 years ago.

"Clearly, this suggests that physicians and patients are not adopting expectant management in lower-risk cancer patients," he said. "The concept behind watchful waiting, or active surveillance, being an effective option for these patients is not novel-it has been in the literature for more than 10 years."

The researchers conducted a logistic regression and compared individuals who had received definitive treatment to watchful waiting and found that patients younger than 55 years were more likely to be treated than those older than 75 years. This statistically significant finding makes clinical sense, according to Dr. Wei, and helps determine where the greatest problems of over-treatment might be.

"Given that the average patient often has bothersome side effects of surgery or radiation, it is important to consider the potential for greater use of expectant management approaches, including active surveillance, particularly among the reasonably large group of men with lower-risk cancers," said lead author David C. Miller, MD, MPH, clinical instructor and research fellow, department of urology, David Geffen School of Medicine at UCLA.