title: Contralateral prophylactic mastectomy in an Asian population: a single institution review.
abstract: BACKGROUND
  Contralateral prophylactic mastectomy (CPM) removes the non-diseased breast in women who have unilateral breast cancer. This reduces the incidence of contralateral breast cancer, and potentially improves survival in high risk patients. Such surgical risk-reduction strategy is increasingly being adopted in the United States, despite a decreasing incidence of contralateral breast cancer. The use of CPM in an Asian population is yet unknown. We present the first Asian report on CPM rates and trends in Singapore, the country with the highest incidence of breast cancer in Asia.
  
  
  METHODS
  A retrospective review of all patients who had breast cancer surgery from 2001 to 2010 at the largest healthcare system in Singapore was performed. Patient demographics and tumour characteristics were analysed with regards to type of surgery performed. Factors associated with CPM were identified.
  
  
  RESULTS
  From 2001 to 2010, a total of 5130 patients underwent oncological breast surgery. A decreasing trend of mastectomies (82.7%-70.8%), an upward trend of breast conserving surgery (BCS) (17.3%-29.2%) and an increasing trend in CPM (0.46%-1.25%) is observed. Patients who opted for CPM are likely to be younger (48.4 ± 9.4 years), married (60%), parous (56.7%), with no family history of breast/ovarian cancer (66.7%), and diagnosed at an earlier stage. The rate of synchronous occult breast malignancy was found to be 10% (n = 30), and these were in patients who were of a low cancer-risk profile.
  
  
  CONCLUSIONS
  This retrospective study reflects an increasing incidence of breast cancer in Singapore, with a decrease in mastectomies, and an increase in BCS and CPM rates, similar to Western data. Similar to Western populations, the Asian woman who opts for CPM is likely to be young and have an earlier stage of breast cancer. In contrast, the Asian woman is likely to have no family history of breast or ovarian cancers. Commonly cited reasons for increased CPM rates such as the increased availability of genetic counselling and pre-operative MRI evaluation, along with wide use of reconstruction, do not feature as dominant factors in our population, suggesting that the Asian patients may have different considerations when electing for CPM.
authors.affiliation: Department of Surgery, Singapore General Hospital, Outram Road, Singapore 169608, Singapore.
authors.forename: Yirong
authors.initials: Y
authors.lastname: Sim
authors.affiliation: Department of Surgical Oncology, National Cancer Centre Singapore, 11 Hospital Drive, Singapore 169610, Singapore.
authors.forename: Veronique Kiak Mien
authors.initials: VK
authors.lastname: Tan
authors.affiliation: Department of Surgical Oncology, National Cancer Centre Singapore, 11 Hospital Drive, Singapore 169610, Singapore.
authors.forename: Gay Hui
authors.initials: GH
authors.lastname: Ho
authors.affiliation: Department of Surgery, Singapore General Hospital, Outram Road, Singapore 169608, Singapore.
authors.forename: Chow Yin
authors.initials: CY
authors.lastname: Wong
authors.affiliation: Department of Surgical Oncology, National Cancer Centre Singapore, 11 Hospital Drive, Singapore 169610, Singapore.
authors.forename: Preetha
authors.initials: P
authors.lastname: Madhukumar
authors.affiliation: Department of Surgery, Singapore General Hospital, Outram Road, Singapore 169608, Singapore.
authors.forename: Benita Kiat Tee
authors.initials: BK
authors.lastname: Tan
authors.affiliation: Department of Surgical Oncology, National Cancer Centre Singapore, 11 Hospital Drive, Singapore 169610, Singapore.
authors.forename: Wei Sean
authors.initials: WS
authors.lastname: Yong
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore, 1E Kent Ridge Road, NUHS Tower Block, Level 11, Singapore 119228, Singapore.
authors.forename: Yvonne Ying Ru
authors.initials: YY
authors.lastname: Ng
authors.affiliation: Department of Surgical Oncology, National Cancer Centre Singapore, 11 Hospital Drive, Singapore 169610, Singapore. Electronic address: ong.kong.wee@nccs.com.sg.
authors.forename: Kong Wee
authors.initials: KW
authors.lastname: Ong
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D044466:Asian People / Q000706:statistics & numerical data*; D001943:Breast Neoplasms / Q000517:prevention & control* / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000517:prevention & control* / Q000601:surgery; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000517:prevention & control* / Q000601:surgery; D018275:Carcinoma, Lobular / Q000517:prevention & control* / Q000601:surgery; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008408:Mastectomy / Q000639:trends*; D015412:Mastectomy, Segmental / Q000639:trends; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000517:prevention & control* / Q000601:surgery; D012189:Retrospective Studies; D012846:Singapore
keywords: BCS; Bilateral breast carcinoma; CBC; CPM; Contralateral breast cancer Asia; Contralateral prophylactic mastectomy; ER; MRI; PR; Prophylactic mastectomy; breast conserving surgery; contralateral breast cancer; contralateral prophylactic mastectomy; magnetic resonance imaging; oestrogen receptor; progesterone receptor