Incidence of hereditary non-polyposis colorectal cancer in a population-based study of 1137 consecutive cases of colorectal cancer.
BACKGROUND
Previous reports have indicated that 5-13 per cent of colorectal cancer is hereditary. However, the proportion of cases arising as a result of mutations in the hereditary non-polyposis colorectal cancer (HNPCC) genes remains to be determined.


METHODS
This study is a part prospective, part retrospective review of all cases of colorectal cancer from a district hospital over 14 years. Some 1137 consecutive patients with colorectal cancer were questioned about their family history of cancer and details were logged on a database. For the past 4 years each case has been re-evaluated where possible.


RESULTS
Some 118 patients indicated initially that they had a first-degree relative with colorectal cancer, but on re-evaluation there were significant discrepancies. Only three cases (0.3 per cent) occurred in families which strictly fulfilled the criteria for HNPCC and there were no cases of familial adenomatous polyposis. A total of 16 patients (1.4 per cent) fulfilled looser criteria for HNPCC.


CONCLUSIONS
This population-based study has shown a lower frequency of familial bowel cancer than previous studies and may reflect a lower incidence of inherited mutations in the HNPCC DNA mismatch repair genes than is currently accepted.
Evans
D G
DG
Department of Medical Genetics, St Mary's Hospital, Manchester, UK.
Walsh
S
S
Jeacock
J
J
Robinson
C
C
Hadfield
L
L
Davies
D R
DR
Kingston
R
R
D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000453:epidemiology*; D004198:Disease Susceptibility; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D011446:Prospective Studies; D012189:Retrospective Studies