title: Fifty-three years of reporting colorectal cancer in Nigerians--a systematic review of the published literature.
abstract: OBJECTIVE
  This study aimed to perform a systematic review of all the available published data on CRC in Nigerians over a period of 53 years as a proximate indication of the burden of the disease.
  
  
  METHODS
  The data were sourced from PubMed, MEDLINE, EMBASE and Google Scholar search engines as well as direct contact with some authors. All published studies on histologically confirmed CRC in Nigerians constitute the materials. Selected papers were independently reviewed by the authors.
  
  
  RESULTS
  Of 35 papers found, 19 met the criteria and a total of 2497 cases reported in these 19 publications constituted the materials utilised for the review. There is increasing incidence as evident by increase in annual frequency increased from 18.2/annum in the early years (1954-1969) to 86.8/annum in the latter years (1991-2007). The average age incidence was 46 years (peak=41-50 age group); 674 (32%) of all the cases were aged below 40 years. The male to female ratio was 1.3:1. Of the 2238 cases in which site was reported, rectum 1349 (60%) was the commonest site followed by caecum 260 (17%). All the cases were adenocarcinomas and 1043 (56%) were well differentiated. Mucinous carcinoma and signet ring type accounted for 309 (17%) and 32 (2%) respectively. Of 1061 cases in which Duke's staging was reported, 622 (59%) presented in stage B disease followed by stage C 266 (25%).
  
  
  CONCLUSIONS
  The incidence is of CRC is increasing in Nigeria. The mean age is low and incidence appears to be increasing in younger patients.
authors: Olorunda
authors: O
authors: Rotimi
authors: Fatimah B
authors: FB
authors: Abdulkareem
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology*; D002288:Adenocarcinoma, Mucinous / Q000453:epidemiology; D000328:Adult; D018279:Carcinoma, Signet Ring Cell / Q000453:epidemiology; D003110:Colonic Neoplasms / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009549:Nigeria / Q000453:epidemiology; D012004:Rectal Neoplasms / Q000453:epidemiology*