Advanced diagnostic breast cancer imaging: variation and patterns of care in Washington state.

INTRODUCTION: Because receipt of breast imaging likely occurs in nonrandom patterns, selection bias is an important issue in studies that attempt to elucidate associations between imaging and breast cancer outcomes. The purpose of this study was to analyze use of advanced diagnostic imaging in a cohort of patients with breast cancer insured by commercial, managed care, and public health plans by demographic, health insurance, and clinical variables from 2002 to 2009.
METHODS: We identified women with breast cancer diagnoses from a Surveillance Epidemiology and End Results (SEER) registry whose data could be linked to claims from participating health plans. We examined imaging that occurred between cancer diagnosis and initiation of treatment and classified patients according to receipt of (1) mammography or ultrasound only; (2) breast magnetic resonance imaging (MRI); and (3) other advanced imaging (computed tomography [CT] of the chest, abdoment, and pelvis; positron emission tomography [PET]; or PET-CT). We used logistic regression to identify factors associated with receipt of breast MRI as well as other advanced imaging.
RESULTS: Commercial health plan, younger age, and later year of diagnosis were strongly associated with receipt of breast MRI and other advanced imaging. Women with prescription drug plans and those who had less comorbidities were more likely to have received breast MRI.
CONCLUSION: Use of breast MRI and other advanced imaging is increasing among patients newly diagnosed with breast cancer; individual patient and insurance-related factors are associated with receipt of these imaging tests. Whether use of diagnostic advanced imaging affects outcomes such as re-excision, cancer recurrence, mortality rates, and costs of breast cancer treatment remains to be determined.