title: Changing epidemiology of colorectal cancer makes screening sigmoidoscopy less useful for identifying carriers of colorectal neoplasms.
abstract: BACKGROUND
  There is renewed interest in flexible sigmoidoscopy (FS) colorectal cancer (CRC) screening following trials showing significantly reduced CRC incidence and mortality.
  
  
  OBJECTIVE
  To evaluate the potential usefulness of FS screening in our population.
  
  
  METHODS
  We examined rectosigmoid (RS) cancer epidemiology in our Jewish population using Israel National Cancer Registry data, computed by CRC site, age groups, and gender. We also reviewed endoscopy-screening publications for prevalence of RS and proximal advanced adenomas (AAP) and having both or either.
  
  
  RESULTS
  During 1980-2008, there were 64,559 CRCs registered; 31.6 % were RS cancer which has now decreased to 29 % of men's and 26 % of women's CRC (both P < 0.01). In <50 year olds, RS cancer occurred in 42 % of males' and 35 % of females' CRC, and in the last 2 decades this ratio is unchanged. In 50-74 year olds, RS cancer decreased to stable levels of 32 % of males' and 29 % females' CRC (both P < 0.01). In ≥75 year olds, RS cancer progressively decreased to 24 % of males' and 22 % females' CRC (both P < 0.001). From endoscopy screening reports in 40-79 year olds, RS AAPs occurred in 2.0-5.8 %, being least in women, most in men, and not increased with aging. Some 50-57 % of screenees had both RS and proximal AAPs, least when aged 40-49 years at 25 %, women were 35 %, and with aging 40 %, but most in men at 70 %.
  
  
  CONCLUSIONS
  With the changing CRC epidemiology, having fewer RS neoplasms but more proximal cancer, the effectiveness of FS screening for identifying significant neoplasms decreases with screenees' age and especially in females. These make FS screening less suitable for our aging and increasingly female population.
authors.affiliation: Sestopali Fund for Gastrointestinal Cancer Prevention, Department of Gastroenterology, Tel Aviv Medical Center, 6 Weizmann Street, 64239 Tel Aviv, Israel. prozen@012.net.il
authors.forename: Paul
authors.initials: P
authors.lastname: Rozen
authors.forename: Irena
authors.initials: I
authors.lastname: Liphshitz
authors.forename: Micha
authors.initials: M
authors.lastname: Barchana
mesh_terms: D018256:Adenomatous Polyps / Q000453:epidemiology; D000367:Age Factors; D000368:Aged; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D007557:Israel / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012737:Sex Factors; D012812:Sigmoidoscopy