Objective: Improvements in imaging technology over time have led to its increasingly widespread use in health care, even when the imaging may not be indicated. This study evaluates patterns of preoperative ultrasound, CT and MRI use among uterine cancer patients in Ontario.
Methods: This population-based study identified women diagnosed with uterine malignancy from 1995-2005 in the Ontario Cancer Registry. Record linkages were made to other healthcare databases to characterize residence, socioeconomic status, comorbidities, and timing of investigations surrounding diagnosis.
Results: We identified 12,522 women who received surgery for uterine adenocarcinoma or sarcoma, of which 9145 (73%) had a preoperative ultrasound, and 1148 (9.2%) had a preoperative CT and/or MRI. Over 10 years, the rate of CT use increased 4.5-fold while MRI use increased 10.6-fold. There were no significant differences in CT/MRI use among patients with increased comorbidities, urban residence or socioeconomic status. Higher rates of CT/MRI use were associated with non-endometrioid high-risk histology (33.5% vs 14.6%, p<0.0001). Median time from ultrasound to surgery was 11.6 weeks. Time from diagnosis to surgery was 2 weeks longer if a preoperative CT/MRI was done. Half of these tests were ordered by non-gynecologists.
Conclusions: The rate of preoperative CT and MRI use in patients with uterine cancer has increased twice as much as the reported rate in cancer patients overall. Given the questionable utility of preoperative CT/MRI in this disease, guidelines should be developed for use of these imaging tests in uterine cancer, especially when use is associated with a delay in surgery.