Diagnosis of low-risk thyroid cancer has increased, yet researchers have unexpectedly found an increase in the use of postdiagnosis imaging among patients with all stages of disease, according to a report published online in Cancer.
“Greater imaging use clearly contributes to increased costs. Specific to thyroid cancer, increased imaging may identify low-volume recurrent disease that is unlikely to be clinically significant, leading to heightened patient anxiety and potentially unnecessary interventions,” Dr. Jaime L.Wiebel and associates at the University of Michigan wrote.Investigators analyzed the records of 23,669 patients diagnosed with differentiated thyroid cancer from 1991-2009 in the Surveillance, Epidemiology, and End Results-Medicare database, and identified the percentage of patients who underwent a neck ultrasound, I-131 scan, or PET scan during the first 3 years after diagnosis.
“Using the SEER-Medicare database, we unexpectedly found that there was a significant increase in the use of surveillance imaging studies over the past 20 years across all stages of disease,” wrote.
Patients diagnosed after 2000 were more likely to have localized disease (P < .001) and tumors measuring less than 1 cm (P < .001), compared with those diagnosed between 1991 and 2000, and were more likely to undergo neck ultrasound (odds ratio, 2.15; 95% confidence interval, 2.02 to 2.28) and I-131 scan (odds ratio, 1.44; 95% confidence interval, 1.35 to 1.54).
Compared with 1996 through 2004, PET scan use from 2005 to 2009 increased 32.4-fold (P = .001) in patients with localized disease, 13.1-fold (P < .001) in patients with regional disease, and 33.4-fold (P < .001) in patients with distant differentiated thyroid cancer, Dr. Wiebel and her associates reported (Cancer 2015 Jan. 6 [doi: 10.1002/cncr.29210]).
“We demonstrated the increased use of imaging over time despite the diagnosis of smaller, more limited, low-risk thyroid cancer. Although many of the themes presented in the current study are true for other malignancies, the overuse of imaging is highlighted by the increased use in patients with this relatively indolent malignancy,” the researchers wrote.
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