Retrospective Cohort Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Oncol. Jun 10, 2016; 7(3): 302-307
Published online Jun 10, 2016. doi: 10.5306/wjco.v7.i3.302
Contralateral prophylactic mastectomy rate stable at major Canadian breast cancer center
Amanda Roberts, Lakhbir Sandhu, Tulin D Cil, Stefan O P Hofer, Toni Zhong
Amanda Roberts, Lakhbir Sandhu, Department of Surgery, University of Toronto, Toronto, ON M5G 2C4, Canada
Tulin D Cil, Division of General Surgery, University Health Network and Women’s College Hospital, Toronto, ON M5G 2M9, Canada
Stefan O P Hofer, Toni Zhong, Division of Plastic and Reconstructive Surgery, University Health Network, Toronto General Hospital, Toronto, ON M5G 2C4, Canada
Author contributions: Roberts A completed the data collection and prepared the manuscript; Sandhu L analyzed the data; Roberts A, Cil TD and Zhong T developed the research question and concept; Sandhu L, Cil TD, Hofer SOP and Zhong T provided feedback on research and critically appraised manuscript.
Institutional review board statement: Research Ethics Board approval was acquired from the University Health Network and maintained throughout the study.
Informed consent statement: Not applicable.
Conflict-of-interest statement: None of the authors declare any conflicts of interest and/or commercial involvement.
Data sharing statement: There is no additional data available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Correspondence to: Toni Zhong, MD, MHS, FRCSC, Associate Professor, Division of Plastic and Reconstructive Surgery, University Health Network, Toronto General Hospital, 8N-871, Toronto, ON M5G 2C4, Canada.
Telephone: +1-416-3403858
Received: January 30, 2016
Peer-review started: January 30, 2016
First decision: March 24, 2016
Revised: April 16, 2016
Accepted: May 7, 2016
Article in press: May 9, 2016
Published online: June 10, 2016

AIM: To examine trends of contralateral prophylactic mastectomy (CPM) rates at a Canadian academic breast cancer center.

METHODS: A single-institution retrospective cohort study was completed. Women of any age who underwent at least a unilateral mastectomy (UM) for primary unilateral breast carcinoma between January 1, 2004 and December 31, 2010 were included. Patients who underwent CPM on the same day as UM were isolated to create two distinct cohorts. Patient and procedure characteristics were compared across groups using R software (version 3.1.0). The percentage of CPMs per year was determined. The Cochrane-Armitage test was used to assess the trend of CPMs over time. A P value of < 0.05 was considered significant.

RESULTS: A total of 811 women met the inclusions/exclusion criteria; 759 (93.6%) underwent UM alone and 52 (6.4%) underwent UM with immediate CPM. The absolute number of procedures (UM and UM + CPM) increased over time, from 83 in 2004 to 147 in 2010 reflecting an increase in mastectomy volume. Annual CPM rates did not increase over time (P = 0.7) and varied between 2.6% to 10.7%. Family history of breast cancer [OR 3.6 (1.8-7.3)] and immediate reconstruction [10.0 (5.2-19.3)] were both significantly associated with CPM. Women who underwent CPM were younger (median age CPM 49 years vs UM 52 years, P < 0.0001) but age less than 50 years was not statistically associated with increased rates of CPM.

CONCLUSION: CPM rates from 2004 to 2010 at a high-volume Canadian breast cancer center did not increase over time, in contrast to trends observed in the United States.

Keywords: Breast, Oncology, Prophylactic, Mastectomy, Surgery

Core tip: Contralateral prophylactic mastectomy rates from 2004 to 2010 at a high-volume Canadian breast cancer center do not demonstrate the same rising trend observed in the United States.