Study finds diagnosing physicians influence therapy decisions for prostate cancer patients

(Press-News.org) New research from The University of Texas MD Anderson Cancer Center is shedding light on the important role a diagnosing urologist plays in whether older men with low-risk prostate cancer receive treatment for their disease, and if so, the type of treatment they receive as a result.

The findings, published in JAMA Internal Medicine, sought to examine why active surveillance, a management program for low-risk disease, which includes repeat PSAs, prostate exams and biopsies, is underused in this patient population.

According to the American Cancer Society, 233,000 new cases of prostate cancer will be diagnosed this year, making it the most common non-skin cancer in men. Previous studies have shown mortality rates are similar for those who opt for surveillance versus treatment in this older population, yet many men continue to incur unnecessary treatment harms.

"What's striking was just how much variation exists in managing prostate cancer, with the diagnosing physician playing as much a role, if not more of a role, than accepted patient factors that impact surveillance use," said Karen Hoffman, M.D., assistant professor in Radiation Oncology and lead author.

Using the Surveillance, Epidemiology and End Results (SEER) registry, researchers identified 12,068 men ages 66 and older diagnosed with low-risk prostate cancer from 2006—2009. Physician characteristics were obtained from linked Medicare claims to determine variations attributable to medical degree, year of training, training location and board certifications.

The main outcome was no cancer-directed therapy within 12 months of diagnosis. Researchers also set to determine the impact of the diagnosing urologist on treatment decisions, quantify the rate of surveillance versus treatment and identify urologist and patient factors associated with surveillance selection.

Results Indicate Widespread Differences

Of the 12,068 men, 80 percent received treatment and only 20 percent underwent observation. Observation rates varied significantly across urologists, from 4.5 to 64.2 percent, and radiation oncologists, from 2 to 47 percent.

Interestingly, researchers found the diagnosing urologist accounted for more than double the rate of variation seen in treatment versus observation decisions compared to individual patient characteristics such as age, comorbidities and PSA level.

Patients diagnosed by urologists who treated low-risk prostate cancer were more likely to receive treatment, and when treated, more likely to receive a therapy their diagnosing urologist used. Hoffman said these findings suggest that physicians not only influence decision making, but the type of treatment selected.

For example, the research found that patients diagnosed by urologists who billed for external beam radiation therapy were more likely to receive it, bringing financial considerations into the fold. The study could not determine those physicians with ownership interests in radiation equipment, but the finding that was also referenced in earlier reports underscores a possible rationale behind some of the disparity.

The authors note public reporting of physician's cancer management profiles would enable primary care providers and patients to make more informed decisions when selecting a physician to diagnose and treat their prostate cancer.

"Primary care physicians play a key role because they refer patients to urologists for elevated PSA levels and prostate biopsies. Increasing transparency could lead to selecting physicians more open to surveillance," Hoffman said.

The authors note several limitations to the study. Those included shifting practice patterns that may influence treatment decisions and the inability to measure certain factors that may impact treatment choice, such as family history and patient anxiety.

Follow-up work in this area will evaluate if patient counseling in a multidisciplinary setting and patient decision aids increase active surveillance acceptance.

INFORMATION: This work was supported by grants from the Cancer Prevention and Research Institute of Texas (RP101207), the National Cancer Institute (T32CA77050, CA079466), the American Cancer Society (RSGI-09-149-01-CPHPS), the McCombs Institute, Center for Radiation Oncology Research at MD Anderson and the National Cancer Institute (P30CA016672).

In addition to Hoffman, other authors on the all MD Anderson study include: Benjamin Smith, M.D., Grace Smith, M.D., Ph.D., Thomas Buchholz, M.D., George Perkins, M.D., Deborah Kuban, M.D. of Radiation Oncology; Sharon Giordano, M.D. and Jiangong Niu, Ph.D. of Health Services Research; Yu Shen, Ph.D. and Jing Jiang of Biostatistics; John Davis, M.D. and Jay Shah, M.D. of Urology; Jeri Kim, M.D. of Genitourinary Medical Oncology; and Robert Volk, Ph.D., General Internal Medicine.

Disclosures: Hoffman receives research support from the American Society for Radiation Oncology and Benjamin Smith receives funding from Varian Medical Systems.