Advanced imaging modalities in early stage breast cancer: preoperative use in the United States Medicare population

Abstract

Background: Guidelines for breast cancer staging exist, but adherence remains unknown. This study evaluates patterns of imaging in early stage breast cancer usually reserved for advanced disease.

Methods: Surveillance Epidemiology, and End Results data linked to Medicare claims from 1992-2005 were reviewed for stage I/II breast cancer patients. Claims were searched for preoperative performance of computed tomography (CT), positron emission tomography (PET), bone scans, and brain magnetic resonance imaging (MRI) ("advanced imaging").

Results: There were 67,874 stage I/II breast cancer patients; 18.8% (n=12,740) had preoperative advanced imaging. The proportion of patients having CT scans, PET scans, and brain MRI increased from 5.7% to 12.4% (P<0.0001), 0.8% to 3.4% (P<0.0001) and 0.2% to 1.1% (P=0.008), respectively, from 1992 to 2005. Bone scans declined from 20.1% to 10.7% (P<0.0001). "Breast cancer" (174.x) was the only diagnosis code associated with 62.1% of PET scans, 37.7% of bone scans, 24.2% of CT, and 5.1% of brain MRI. One or more symptoms or metastatic site was suggested for 19.6% of bone scans, 13.0% of CT, 13.0% of PET, and 6.2% of brain MRI. Factors associated (P<0.05) with use of all modalities were urban setting, breast MRI and ultrasound. Breast MRI was the strongest predictor (P<0.0001) of bone scan (odds ratio [OR] 1.63, 95% confidence interval [CI] 1.44-1.86), Brain MRI (OR 1.74, 95% CI 1.15-2.63), CT (OR 2.42, 95% CI 2.12-2.76), and PET (OR 5.71, 95% CI 4.52-7.22).

Conclusions: Aside from bone scans, performance of advanced imaging is increasing in early stage Medicare breast cancer patients, with limited rationale provided by coded diagnoses. In light of existing guidelines and increasing scrutiny about health care costs, greater reinforcement of current indications is warranted.

Figure 1

Imaging trends from 1992 to 2005. Panels represent: (A) CT Scans, (B) PET Scans, (C) Brain MRIs, and (D) Bone Scans. In all panels, the x-axis represents the year and total number of sample patients having stage I and II breast cancer in that year. For panel (B), the thin arrow represents the year in which PET Scans were FDA approved for use in cancer patients, while the thick arrow represents the year in which PET scans were approved by Medicare for use in breast cancer patients specifically.