title: Opportunistic breast cancer screening by mammography in Japan for women in their 40s at our preventive medical center: harm or benefit?
abstract: BACKGROUND
  After recent revised grading by the US Preventive Services Task Force of mammography (MMG) recommendations for women in their 40s, it is urgent to collect data on the benefits and harm of MMG screenings in Japan. In this paper, we study the actual status and effectiveness of opportunistic breast cancer screening by MMG for women in their 40s.
  
  
  METHODS
  From January to December 2008, the total number of opportunistic breast cancer screenings by MMG at our institute was 12823. Of them, 398 (3.1 %) who were diagnosed as category 3 or more on MMG required further exams. The data were compared between two groups (women in their 40s, women aged 50 and older). Recall rate, detection rate of breast cancers, and implementation rate of further exams were evaluated.
  
  
  RESULTS
  Recall rate was 4.0 % (166/4138) for women in their 40s and 2.4 % (166/6949) for women aged 50 and older. Detection rate of breast cancers was higher in women in their 40s (0.56 %) than women aged 50 and older (0.26 %). Non-cancer rate among women receiving invasive examination was higher in women in their 40s (0.76 %) than women aged 50 and older (0.42 %) (p = 0.02). The number of false positives required to detect one true cancer patient was smaller in women in their 40s (4.5) than women aged 50 and older (5.3).
  
  
  CONCLUSIONS
  The results from our single institute revealed that opportunistic breast cancer screening by MMG for women in their 40s shows higher net benefits than for women aged 50 and older.
authors.affiliation: Department of Radiology, St. Luke's International Hospital, 9-1 Akashi-cho, Chuo-ku, Tokyo, 104-8560, Japan, marikiku@luke.or.jp.
authors.forename: Mari
authors.initials: M
authors.lastname: Kikuchi
authors.forename: Hiroko
authors.initials: H
authors.lastname: Tsunoda
authors.forename: Tomomi
authors.initials: T
authors.lastname: Koyama
authors.forename: Toshiko
authors.initials: T
authors.lastname: Kawakita
authors.forename: Koyu
authors.initials: K
authors.lastname: Suzuki
authors.forename: Hideko
authors.initials: H
authors.lastname: Yamauchi
authors.forename: Osamu
authors.initials: O
authors.lastname: Takahashi
authors.forename: Yukihisa
authors.initials: Y
authors.lastname: Saida
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D055088:Early Detection of Cancer; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007564:Japan; D008327:Mammography; D008403:Mass Screening / Q000706:statistics & numerical data*; D008875:Middle Aged