title: Invasive Breast Cancer Incidence in 2,305,427 Screened Asymptomatic Women: Estimated Long Term Outcomes during Menopause Using a Systematic Review.
abstract: BACKGROUND
  Earlier studies of breast cancer, screening mammography, and mortality reduction may have inflated lifetime and long-term risk estimates for invasive breast cancer due to limitations in their data collection methods and interpretation.
  
  
  OBJECTIVE
  To estimate the percentage of asymptomatic peri/postmenopausal women who will be diagnosed with a first invasive breast cancer over their next 25 years of life.
  
  
  METHODS
  A systematic review identified peer-reviewed published studies that: 1) enrolled no study participants with a history of invasive breast cancer; 2) specified the number of women enrolled; 3) reported the number of women diagnosed with a first invasive breast cancer; 4) did not overcount [count a woman multiple times]; and, 5) defined the length of follow-up. Data sources included PubMed, Cochrane Library, and an annotated library of 4,409 full-text menopause-related papers collected and reviewed by the first author from 1974 through 2008. Linear regression predicted incidence of first invasive breast cancer, based on follow-up duration in all studies that met the our inclusion criteria, and in a subset of these studies that included only women who were 1) at least 50 years old and 2) either at least 50 or less than 50 but surgically menopausal at enrollment.
  
  
  RESULTS
  Nineteen studies met the inclusion criteria. They included a total of 2,305,427 peri/postmenopasual women. The mean cumulative incidence rate of first invasive breast cancer increased by 0.20% for each year of age (95% CI: 0.17, 0.23; p < 0.01; R2 = 0.90). Over 25 years of follow-up, an estimated 94.55% of women will remain breast cancer-free (95% CI: 93.97, 95.13). In the 12 studies (n = 1,711,178) that enrolled only postmenopausal women, an estimated 0.23% of women will be diagnosed with a first invasive breast cancer each year (95% CI: 0.18, 0.28; p < 0.01, R2 = 0.88).
  
  
  CONCLUSIONS
  The vast majority (99.75%) of screened asymptomatic peri/postmenopasual women will not be diagnosed with invasive breast cancer each year. Approximately 95% will not be diagnosed with invasive breast cancer during 25 years of follow-up. Women who receive clinical examinations, but do not have mammograms, will have higher cancer-free rates because innocuous positives (comprising 30-50% of mammography diagnoses) will remain undetected. Informed consent to asymptomatic women should include these results and consideration of the benefits of avoiding mammograms.
authors.affiliation: Department of Women's Health Research, Athena Institute for Women's Wellness, Chester Springs, Pennsylvania, United States of America.
authors.forename: Winnifred
authors.initials: W
authors.lastname: Cutler
authors.affiliation: Department of Gynecology, Hirslanden Hospital Group, Bern, Switzerland.
authors.forename: Regula
authors.initials: R
authors.lastname: Bürki
authors.affiliation: Department of Obstetrics and Gynecology, The Philadelphia College of Osteopathic Medicine, Philadelphia, Pennsylvania, United States of America; Department of Obstetrics and Gynecology, Paoli Hospital, Paoli, Pennsylvania, United States of America.
authors.forename: James
authors.initials: J
authors.lastname: Kolter
authors.affiliation: Department of Psychology, Ursinus College, Collegeville, Pennsylvania, United States of America.
authors.forename: Catherine
authors.initials: C
authors.lastname: Chambliss
authors.affiliation: School of Nursing, University of Maryland, Baltimore, Maryland, United States of America.
authors.forename: Erika
authors.initials: E
authors.lastname: Friedmann
authors.affiliation: Department of Mathematics and Computer, The Hotchkiss School, Lakeville, Connecticut, United States of America.
authors.forename: Kari
authors.initials: K
authors.lastname: Hart
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D058070:Asymptomatic Diseases; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology; D055088:Early Detection of Cancer / Q000706:statistics & numerical data*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D015994:Incidence; D008327:Mammography; D008593:Menopause; D008875:Middle Aged; D010808:Physical Examination; D011336:Probability; D011379:Prognosis