Diagnosing docs strongly influence PCa Tx decisions

Diagnosing physicians-urologists in particular-significantly influence decision making in men with low-risk prostate cancer as well as the type of treatment selected, according to researchers from The University of Texas MD Anderson Cancer Center in Houston.

Their study, published online in JAMA Internal Medicine (July 14, 2014), sought to examine why active surveillance is underused in men with low-risk disease.

“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 lead author Karen Hoffman, MD in a news release.

Using the Surveillance, Epidemiology, and End Results registry, Dr. Hoffman and colleagues identified 12,068 men ages 66 years and older diagnosed with low-risk prostate cancer from 2006 to 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 a year 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.

Eighty percent of the men received treatment and 20% underwent surveillance. Observation rates varied significantly across urologists, from 4.5% to 64.2%, and radiation oncologists, from 2% to 47%.

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, according to the authors.

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. Dr. Hoffman said these findings suggest that physicians not only influence decision making, but the type of treatment selected.

The research found, for example, that patients diagnosed by urologists who billed for external beam radiation therapy were more likely to receive it. The study could not determine those physicians with ownership interests in radiation equipment.

The authors note several limitations to the study, including 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.

Dr. Hoffman receives research support from the American Society for Radiation Oncology and a study co-author receives funding from Varian Medical Systems.