Abstract P5-13-13: Non-clinical drivers of variation in preoperative MRI utilization for breast cancer
Authors: Pak LM , Banaag A , Koehlmoos TP , Haider AH , Learn PA 
Published: May 2019

Abstract
Background: Preoperative MRI utilization in breast cancer treatment has increased significantly over the past two decades but its use continues to have inter-provider variability and disputed clinical indications. The objective of this study was to evaluate non-clinical factors associated with preoperative breast MRI utilization.
Methods: This study utilized claims from the Military Health System Data Repository (MDR) on TRICARE Prime beneficiaries, from fiscal years 2006-2015. TRICARE provides health benefits for Active Duty service members, retirees, and their dependents at both military (direct care with salaried physicians) and civilian (purchased care with fee-for-service physicians) treatment facilities. We studied patients aged 25-64 years old with a breast cancer diagnosis who had undergone mammogram/breast ultrasound alone or with subsequent breast MRI prior to surgery. Patient demographics and treatment characteristics were abstracted from the data. The National Center for Health Statistics (NCHS) urban-rural classification was used to determine the urbanization level of the treatment facility. Adjusted multivariate logistic regression tests were used to identify independent factors associated with preoperative breast MRI utilization.
Results: Of the 25,656 identified patients, 64.4% of patients (n=16,511) received preoperative mammogram/breast ultrasound alone while 35.6% of patients (n=9,145) underwent additional MRI after mammographic and/or ultrasound imaging. On multivariable analysis, younger age, presence of two or more comorbidities, active duty or retired beneficiary category, officer rank (surrogate for socioeconomic status), Air Force service branch, metropolitan location, and purchased care were associated with increased likelihood of preoperative MRI utilization. Nonmetropolitan location and Navy service branch were associated with decreased MRI use.
Odds Ratio95% Confidence IntervalAge Group (Ref: 55-64 years)25-34 years1.851.60-2.15 35-44 years1.591.47-1.72 45-54 years1.271.19-1.35Charlson Comorbidity Index (Ref 0-1)2+2.472.33-2.61Beneficiary Category (Ref: Dependent)Active Duty1.201.04-1.38 Retired1.231.09-1.40Rank (Ref: Senior Enlisted)Junior Enlisted0.930.78-1.11 Junior Officer1.251.14-1.37 Senior Officer1.481.36-1.60 Warrant Officer1.231.06-1.42Service Branch (Ref: Army)Air Force1.101.03-1.18 Navy0.920.85-0.99 Marines0.950.84-1.07 Coast Guard1.070.89-1.29Urban-Rural Classification (Ref: Medium Metropolitan)Large Central Metropolitan1.801.68-1.93 Large Fringe Metropolitan1.591.47-1.71 Small Metropolitan0.650.59-0.71 Micropolitan0.400.34-0.46 Noncore0.250.18-0.34Treatment Facility Care Setting (Ref: Direct Care)Purchased Care1.601.48-1.73
Conclusions: After controlling for expected clinical risk factors, patients were more likely to receive additional MRI when treated at larger metropolitan facilities or through the purchased, fee-for-service system. Both associations may point toward non-clinical incentives to perform MRI in the treatment of breast cancer.
Citation Format: Pak LM, Banaag A, Koehlmoos TP, Haider AH, Learn PA. Non-clinical drivers of variation in preoperative MRI utilization for breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-13-13.