title: Breast cancer in Chinese women younger than age 40: are they different from their older counterparts?
abstract: BACKGROUND
  Breast cancer in young women is uncommon, but when it does occur it has been reported to have aggressive biological characteristics. The incidence of breast cancer peaks at age 40 in Hong Kong Chinese women, earlier than in Caucasians. This study is the first to report the tumor characteristics and management of breast cancer in Chinese women younger than age 40 and a comparison with their older counterparts.
  
  
  METHODS
  Demographic and clinicopathologic findings of 1,485 Chinese women with breast cancer seen during the period September 2003 to November 2006 were prospectively recorded, and comparisons were made between those who were under the age of 40 and those 40 years of age and older. These results were then compared with a reference population obtained from the Surveillance, Epidemiology and End Results (SEER) database between 2003 and 2004.
  
  
  RESULTS
  17.6% of the women were younger than 40 years old, and age distribution was significantly different from women in the SEER database. The mean age at menarche was lower in women under age 40 (p < 0.0005), and age at first live birth was also higher (p = 0.017). The rate of first detection by screening mammography was significantly higher among women who were 40 of age and older (p = 0.002). Breast conservation surgery was more commonly performed in the younger age group of Chinese women, particularly when tumor size was less than 2 cm (p = 0.001). A significantly higher proportion of women under age 40 had breast reconstruction (p < 0.001). The majority of women presented with stage 0-II disease, but in the Chinese groups the younger patients presented at a later stage (p = 0.04). Younger women had higher pathological grade and poorly differentiated tumors (p = 0.02), more nodal involvement (p = 0.024), and lymphovascular permeation involvement (p < 0.001). The majority of tumors were ER and PR positive in both groups, but younger women had a higher proportion of cerbB2-positive tumors.
  
  
  CONCLUSIONS
  Chinese women present with breast cancer at an earlier age. Younger women present with more advanced disease and more aggressive tumor characteristics. More ethnic-specific screening protocols and treatment decisions may benefit this group of patients.
authors.affiliation: Breast Care Center, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong, China. akwong@asiabreastregistry.com
authors.forename: Ava
authors.initials: A
authors.lastname: Kwong
authors.forename: Polly
authors.initials: P
authors.lastname: Cheung
authors.forename: Stephanie
authors.initials: S
authors.lastname: Chan
authors.forename: Silvia
authors.initials: S
authors.lastname: Lau
mesh_terms: D000328:Adult; D017677:Age Distribution; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000706:statistics & numerical data*; D001943:Breast Neoplasms / Q000208:ethnology* / Q000473:pathology / Q000628:therapy; D015331:Cohort Studies; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D012189:Retrospective Studies; D018426:SEER Program; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data*; D055815:Young Adult