The Impact of Bilateral Mastectomy on Reconstructive Rate and Method In the United States: A Population Based Analysis

Background: The number of bilateral mastectomies is increasing in the US due to rising use of contralateral prophylactic mastectomy.  National rates of bilateral prophylactic mastectomies have not been measured. The influence of changing mastectomy patterns on reconstructive rate and method are unknown. The aim of the current study is: 1) measure trends in the type of mastectomy performed, 2) analyze reconstruction rates and techniques used for the different mastectomy types, 3) determine sociodemographic characteristics of patients undergoing the different mastectomies.

Methods:  Analysis of mastectomies from 1998-2008 was performed using the Nationwide Inpatient Sample (NIS) database, the largest registry of US hospital discharges. Ablative procedures were classified based on ICD-9 diagnosis/procedure codes as either: 1) Unilateral mastectomy (UM), 2) bilateral mastectomies with a unilateral or bilateral cancer diagnosis (BMC), and 3) Bilateral prophylactic mastectomies (BPM). Rates were adjusted per 1,000 mastectomies or reconstructions depending upon the analysis. Lumpectomies were excluded. Longitudinal trends were analyzed with Poisson regression and expressed as incidence rate ratio (IRR). Sociodemographic (SD) variables and reconstructive rates were compared using chi-square.

Results: Information on 178,603 mastectomies was analyzed. UM decreased 2% per year while both BMC and BPM increased significantly by 18% and 12% per year (p<0.01)[Figure 1]. Reconstruction rates increased yearly for all three mastectomy types by 3-5% (p<0.01). BPM and BMC have had consistently higher reconstruction rates than UM throughout the study period [Figure 2]. Patients undergoing unilateral mastectomies were more frequently reconstructed using autologous tissue than patients undergoing either BMC or BPM [Figure 2]. Patients undergoing BPM compared to BMC and UM tended to be: younger, Caucasian, private insurance recipients and operated on at teaching hospitals.

Conclusion: The increasing trend towards bilateral mastectomies within the Unites States has contributed to both higher reconstruction rates and greater use of implant based techniques. Patients undergoing BPM have a unique SD profile compared to patients undergoing mastectomy for a cancer diagnosis.