Associations of preoperative breast magnetic resonance imaging with subsequent mastectomy and breast cancer mortality
To examine associations between pre-operative magnetic resonance imaging (MRI) use and clinical outcomes among women undergoing breast-conserving surgery (BCS) with or without radiotherapy for early-stage breast cancer.
We identified women from the Surveillance, Epidemiology, and End Results-Medicare dataset aged 67–94 diagnosed during 2004–2010 with stage I/II breast cancer who received BCS. We compared subsequent mastectomy and breast cancer mortality with versus without pre-operative MRI, using Cox regression and competing risks models. We further stratified by receipt of radiotherapy for subgroup analyses.
Our sample consisted of 24,379 beneficiaries, 4691 (19.2%) of whom received pre-operative MRI. Adjusted rates of subsequent mastectomy and breast cancer mortality were not significantly different with and without MRI: 3.2 versus 4.1 per 1000 person-years [adjusted hazard ratio (AHR) 0.92; 95% confidence interval (CI) 0.70–1.19] and 5.3 versus 8.7 per 1000 person-years (AHR 0.89; 95% CI 0.73–1.08), respectively. In subgroup analyses, women receiving BCS plus radiotherapy had similar rates of subsequent mastectomy (AHR 1.17; 95% CI 0.84–1.61) and breast cancer mortality (AHR 1.00; 95% CI 0.80–1.24) with versus without MRI. However, among women receiving BCS alone, MRI use was associated with lower risks of subsequent mastectomy (AHR 0.60; 95% CI 0.37–0.98) and breast cancer mortality (AHR 0.57; 95% CI 0.36–0.92).
Pre-operative MRI was associated with improved outcomes among older women with breast cancer receiving BCS alone, but not among those receiving BCS plus radiotherapy. Further research is needed to identify appropriate settings for which MRI may be helpful.
KeywordsMagnetic resonance imaging Outcomes research Competing risks models Risk stratification
The collection of the California cancer incidence data used in this study was supported by the California Department of Public Health as part of the statewide cancer reporting program mandated by California Health and Safety Code Section 103885; the National Cancer Institute’s Surveillance, Epidemiology and End Results Program under Contract N01-PC-35136 awarded to the Northern California Cancer Center, Contract N01-PC-35139 awarded to the University of Southern California, and contract N02-PC-15105 awarded to the Public Health Institute; and the Centers for Disease Control and Prevention’s National Program of Cancer Registries, under agreement #U55/CCR921930-02 awarded to the Public Health Institute. The authors of this report are responsible for its content. The ideas and opinions expressed herein are those of the author(s) and endorsement by the State of California, Department of Public Health the National Cancer Institute, and the Centers for Disease Control and Prevention or their Contractors and Subcontractors is not intended nor should be inferred. The authors acknowledge the efforts of the Applied Research Program, NCI; the Office of Research, Development and Information, CMS; Information Management Services (IMS), Inc.; and the Surveillance, Epidemiology, and End Results (SEER) Program tumor registries in the creation of the SEER-Medicare database. The interpretation and reporting of the SEER-Medicare data are the sole responsibility of the authors.
This investigation was supported by a Pilot Grant and a P30 Cancer Center Support Grant (CCSG), both from Yale Comprehensive Cancer Center.
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Conflict of interest
Dr. Wang receives research support from Genentech. Dr. Gross receives support from Medtronic, Inc., Johnson & Johnson, Inc., and twenty-first Century Oncology. These sources of support were not used for any portion of the current manuscript. None of the other coauthors have conflicts to report.
The Yale Human Investigation Committee determined that this study did not directly involve human subjects. Thus, tis article does not contain any studies with human participants or animals performed by any of the authors.