A recent study of imaging utilization found an association between inappropriate imaging of patients with low-risk prostate cancer and low-risk breast cancer across hospital referral regions (HRRs), suggesting regional-level factors contribute substantially to utilization trends.

“Understanding whether prostate and breast cancer imaging are associated at a regional level might promote more nuanced, regionally tailored interventions, such as legislation, payment reform, and educational initiatives, to improve population health and provide higher-value care,” wrote authors Danil V. Makarov, MD, MHS, of the department of urology at New York University School of Medicine, and colleagues. Their findings appeared online March 12 in JAMA Oncology.

The American Society of Clinical Oncology identified imaging in patients with low-risk prostate or breast cancer as two services that are likely unnecessary under the Choosing Wisely initiative, which seeks to decrease wasteful medical resource use.

Makarov and colleagues targeted these procedures in their retrospective study, and identified 9,219 men with prostate cancer and 30,398 women with breast cancer in the Surveillance, Epidemiology, and End Results–Medicare linked database. The patients were spread throughout 84 HRRs and were diagnosed from 2004 to 2007, a pre-Choosing Wisely era selected to help emphasize regional-level drivers of resource utilization.

Results showed that among those with low-risk (according to Choosing Wisely definitions) prostate cancer, the rate of inappropriate imaging was 44.4 percent. This rate was similarly high among those with low-risk breast cancer at 41.8 percent.

Inappropriate prostate cancer imaging rates were associated with inappropriate breast cancer imaging rates at the HRR level, and a man with low-risk prostate cancer had odds ratios of 1.72, 1.19 or 1.76 for undergoing inappropriate imaging if he lived in HRRs the fourth, third or second quartiles, respectively, of inappropriate breast cancer imaging rates, compared with the lowest quartile.

Makarov and colleagues noted that patients with breast cancer were more likely to undergo resource-intensive imaging than those with prostate cancer. They suggested regions with high rates of inappropriate breast cancer imaging may have access to PET scanners and other infrastructure that could promote imaging, while equipment for prostate cancer imaging is less specialized and regions with high prostate cancer imaging rates may not perform all imaging frequently.

“As patients with prostate cancer and breast cancer are a nonoverlapping cohort treated by nonoverlapping specialists, an association of inappropriate imaging between them suggests that regional culture and infrastructure contribute to health care utilization patterns across diseases,” wrote Makarov et al.

In an associated editorial, Samuel Swisher-McClure, MD, MSHP, and Justin Bekelman, MD, of the department of radiation oncology at the University of Pennsylvania’s Perelman School of Medicine, acknowledged that the study extended understanding of regional correlation between inappropriate imaging for breast and prostate cancers, but they encouraged readers to not lose sight of the related but distinct issue of geographic variation in healthcare utilization overall.

“Although the existence of excess variation in health care spending without improvement in patient outcomes suggests that inappropriate utilization may be a primary explanatory factor, prior studies have indicated that only a small proportion of observed geographic variation in health care spending can be explained by inappropriate use,” wrote Swisher-McClure and Bekelman. “Furthermore, as alluded to in the study by Makarov et al, high-spending regions tend to have higher rates of both appropriate and inappropriate care, while lower-spending regions have lower rates of both appropriate and inappropriate care. This has been referred to as the thermostat model. If correct, it might suggest that policy interventions targeted at the regional level must be designed with extreme care, lest they reduce utilization of appropriate care for patients who need it along with intended reductions in inappropriate care.”