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(Reuters Health) - - Men with prostate cancer that hasn't spread to surrounding tissues are more likely to get radiation therapy if they're diagnosed by doctors who own radiation machines, a Texas study suggests.
Most men with prostate cancer have this kind of tumor. Treatment options include surgery, radiation, or so-called "active surveillance" that involves holding off on treatment and instead doing periodic tests to see if the malignancies grow. Often, doctors and patients struggle to choose the best option, because it's hard to tell which tumors will grow fast enough to be potentially life-threatening and which ones might never get big enough to cause problems.
Some previous research has found when urologists own radiation equipment, men are more likely to get this treatment instead of surgery, said senior study author Dr. Karen Hoffman of the University of Texas MD Anderson Cancer Center in Houston. The current study, however, suggests that equipment ownership might tip the scales in favor of any treatment - either surgery or radiation - over active surveillance.
Compared with men diagnosed by specialists who didn't own radiation machines, men diagnosed by urologists who did own equipment were 61 percent more likely to receive surgery or radiation, researchers report in the journal Prostate Cancer and Prostatic Diseases.
"For patients with very favorable prostate cancer, our findings suggest that urologist ownership of radiation equipment may contribute to unnecessary treatment," Hoffman said by email.
"However, for patients with disease with aggressive features, our findings suggest that urologist ownership increases correct treatment, meaning that these patients who need treatment are more likely to receive it if they are diagnosed by a urologist with an ownership interest in radiation therapy," Hoffman added.
For the study, researchers examined data on 17,982 men diagnosed with localized prostate cancer from 2006 to 2009 in Texas.
Most of the men in the study were 66 to 70 years old, white, and without other major medical problems.
During the study period, the percentage of men diagnosed by urologists who owned equipment increased from about 2 percent to almost 25 percent.
Men diagnosed with so-called favorable risk disease, meaning tumors less likely to grow and spread enough to be dangerous, were 89 percent more likely to receive treatment instead of active surveillance when their doctor owned radiation equipment, the study found.
With so-called unfavorable risk disease, or tumors more likely to become lethal, men were more than twice as likely to receive treatment instead of active surveillance when their urologist owned equipment.
Equipment ownership was also associated with higher odds than men would receive external beam radiation (EBRT). Men with favorable risk were 45 percent more likely to get EBRT when urologists owned machines, and men with unfavorable risk were 53 percent more likely to get EBRT with equipment ownership.
The average annual cost of treatment was typically more than $2,000 higher for men who were seen by urologists who owned equipment than for men who were seen by specialists without an ownership stake in the machines.
One limitation of the study is that researchers couldn't account for patient preferences or other factors such as urinary, bowel and sexual function that may influence the care men receive, the authors note.
Still, the findings add to a growing body of evidence suggesting that equipment ownership influences treatment decisions, Dr. Lih-Ming Wong, a urology researcher at the University of Melbourne who wasn't involved in the study, said by email.
"Allowing physicians to self-refer may lead to unnecessary treatment and added health care costs to society and patients," said Dr. Quick-Dien Trinh, a urology researcher at Brigham and Women's Hospital and the Dana Farber Cancer Institute Prostate Cancer Program.
"That said, to be fair, the study does not tell us if self-referral practices merely diverted their previous use of radiation therapy from another facility to theirs," Trinh, who wasn't involved in the study, said by email. "However, it doesn't explain why self-referral practices are more likely to use radiation therapy regardless of disease risk."
SOURCE: go.nature.com/2paXJD7 Prostate Cancer and Prostatic Diseases, online March 28, 2017.