Imaging use is growing faster for Medicare stage IV cancer patients than for those at earlier stages, according to a study published in the Journal of the National Cancer Institute.
The results suggest overuse in patients with advanced cancer, and highlight a need for better clinical guidelines, according to an announcement of work from a research group from the Dana-Farber/Harvard Cancer Center, Brigham and Women's Hospital, and the University of Wisconsin.
The researchers compared imaging rates and frequency of exams between stage IV patients (105,594) and a second group in stage I or stage II (86,835) drawn from a population of Medicare patients listed in the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) cancer registry, AuntMinnie.com reports. They tracked the four cancers that most frequently lead to death: breast, colorectal, lung, or prostate cancer.
Advanced imaging--CT, MRI, nuclear medicine, PET/CT, and PET--in the stage IV group grew by 4.6 percent from 1995 to 2006, while it fell by 2.5 percent in the stage I and II group.
The average number of scans per person per month grew in the lesser stages, but more slowly than for those in stage IV. When divided into a "diagnostic" phase, "continuing-care" phase and "end-of-life" phase, only the initial phase showed higher imaging rates than the final phase.
"Because scans help clinicians determine whether a change in [or cessation of] treatment is indicated, the expanding use of advanced imaging in stage IV disease is likely a manifestation of the increasing number and types of treatment options available to these patients," the authors said, according to the announcement.
Despite changes in treatment, though, the researchers said that survival rates among stage IV patients has changed only modestly. They also noted that several national guidelines were published during the study period calling for more limited use of imaging for patients with stage I and II disease.
Though imaging can lead to appropriate palliative measures it can also distract patients and caregivers from the focus on quality of life they said.
In an accompanying editorial, epidemiologists K. Robin Yabroff and Joan Warren, of the U.S. National Cancer Institute's Health Services and Economics Branch said that guidelines must be informed by better evidence about the incremental benefit of advanced imaging.
A recent study published at Health Affairs noted that advanced imaging for Medicare beneficiaries grew at more than 6 percent per year until 2006, then slowed to between 1 and 3 percent annually until 2009. The American College of Radiologists, however, called that work incomplete and potentially misleading.
HMO imaging rates, in a University of California, San Francisco study, were found to be similar to those of Medicare patients, for whom previous research had attributed the increases in part to fee-for-service payment models that reward doctors for ordering the costly tests.