Impact of Age, Rurality and Distance in Predicting Contralateral Prophylactic Mastectomy for Breast Cancer in a Midwestern state: A Population-Based Study

Abstract Background: There is substantial variability in the use of contralateral prophylactic mastectomy (CPM) in women with unilateral breast cancer across the United States. Iowa is one of several rural Midwestern states found to have the highest proportions of CPM nationally in women <45 years of age. We evaluated the role of rurality and travel distance as factors related to these surgical patterns.Methods: Women with unilateral breast cancer (2007-2017) were identified using Iowa Cancer Registry records. Patients and treating hospitals were classified as metro, nonmetro and rural based on Rural-Urban Continuum Codes. Differences in patient, tumor, and treatment characteristics and median travel distances (MTD) were compared. Characteristics associated with CPM were evaluated with multivariate logistic regression.Results: 22,158 women were identified: 57% metro, 26% nonmetro and 18% rural. The overall proportion of CPM in Iowa was consistently higher than in the national Surveillance, Epidemiology, and End Results (SEER18) throughout the interval from 2007-2015. Young rural women had the highest proportion of CPM (<40 years: 52%, 39% and 40% for rural, metro, nonmetro, respectively). Half of all rural women had surgery at metro hospitals; these women had the longest MTD (56 miles). Of all women treated at metro hospitals, rural women had the highest proportion with CPM (17% rural; vs 14% metro/nonmetro, p=0.007). On multivariate analysis, traveling ≥50 miles (ORs 1.48-2.34) or being rural regardless of travel distance was predictive of CPM (OR = 1.36). Other risk factors were young age (<40 years: OR=7.18, 95% CI: 5.89-8.76) and surgery at a metro hospital that offers reconstruction (OR=2.3, 95% CI: 1.70-3.21) and is not NCI-designated (OR=2.19, 95% CI: 1.78-2.69).Conclusion: There is an unexpectedly high proportion of CPM use in young rural women in Iowa. Travel ≥50 miles and rural residence are independently associated with likelihood of CPM. Disparities in access to specialty care may underlie the desire for surgery that is perceived to minimize follow-up visits.