TUESDAY, Nov. 30 (HealthDay News) -- Using a computer simulation model, researchers say they've determined that relying on "active surveillance" to follow men with low-risk prostate cancer is a "reasonable approach" and alternative to immediate treatment, which can cause unwanted side effects such as incontinence and impotence.

If the tumor were to start growing again, treatment options could include intensity-modulated radiation therapy (IMRT), which uses beams of different radiation intensities to limit damage to surrounding areas of the body, the study authors said.

"The intent of this study is to show that, on average, showing average disease-recurrence probabilities, an average rate of side effects and average individual preferences, active surveillance was an option," said Dr. Julia H. Hayes, lead author of the study published in the Dec. 1 issue of the Journal of the American Medical Association.

But the computer model isn't intended to replace personal decision-making for prostate cancer patients, all of whom have vastly different comfort levels when it comes to how they handle their diagnosis of cancer, the researchers said.

Still, the model might serve as a jumping-off point for doctor-patient discussions, and may provide more impetus for men to choose active surveillance and avoid unnecessary treatment, the researchers added.

Each year, some 200,000 U.S. men are diagnosed with prostate cancer. While about 60 percent of those men don't actually need treatment (because their tumors are low risk and localized), more than 90 percent will still be treated, said Hayes, who is a genitourinary oncologist with the Dana-Farber Cancer Institute and an instructor in medicine at Harvard Medical School.

Active surveillance involves following men closely with prostate-specific antigen (PSA) tests, digital rectal examinations and regular biopsies. If the disease turns out to be more aggressive than initially thought, "they can be treated with curative intent," Hayes said. "The goal is to not treat those who don't need to be treated."

Studies to determine the effectiveness of active surveillance would take decades to complete and researchers simply don't have long-term data yet on how wise this strategy really is.

So, the computer model involved a hypothetical group of 65-year-old men with localized, low-risk prostate tumors.

The patients were treated first with brachytherapy (placing radioactive "seeds" in or near the tumor), IMRT, a radical prostatectomy (removal of the prostate gland) or they were followed using active surveillance.

Then the researchers used a measure called Quality-Adjusted Life Expectancy (QALE) to compare active surveillance to initial treatment. QALE measures both the quality and length of each patient's life.

Active surveillance (and IMRT later if needed) was associated with more QALE at 11.07 quality-adjusted life years (QALYs). Brachytherapy produced a 10.57 QALYs rating, followed by IMRT at 10.51 QALYs, and surgery to remove the prostate at 10.23 QALYs.

QALYs are a measure often used by scientists to indicate "the number of good quality years of life left," explained Dr. Stephen Freedland, associate professor of surgery at Duke University Medical Center, who was not involved with the study. Basically, it refers to how many "good" years are left.

And therein lie some of the complexities of translating these findings into the real world of real men.

"It depends on your definition of 'good,'" Freedland said. "The complications we are discussing are bowel problems, urinary problems and sexual problems. They [patients] are not being tied to a ventilator or being bed-bound. So, while important and significant, they are all in your interpretation of 'good.' Some men just don't care about erectile dysfunction. It's all about seeing their grandkids grow up. For others, sexual function is paramount and they would be willing to trade some quantity of life for quality of life."

"If someone has had a brother who has died of prostate cancer and is anxious about it, their [preference] is going to be lower, so [active surveillance is] probably not an appropriate approach," Hayes added.

So then the challenge is picking which patients are right for active surveillance.

"I wholeheartedly agree with the essential premise that for the right patient this is a reasonable choice. The challenge is, who is the right patient?" Freedland asked. "I feel very comfortable suggesting this for a man with low-risk cancer who is 65, but what happens when he's 55 or 45? The chances of him having a problem in the next 10 years are really low but he has 35 years to live," he said.

"The chance that his cancer will need to be treated in the next 35 years is probably reasonably high so why not treat it now?" Freedland added. "That's not my argument but that's the elephant in the room."

More information

The U.S. National Cancer Institute has more on prostate cancer.