FAMILY HISTORY OF COLORECTAL TUMORS AND IMPLICATIONS FOR THE ADENOMA-CARCINOMA SEQUENCE - A CASE-CONTROL STUDY

Family history of colorectal cancer is a risk factor for sporadic colo rectal cancer, but it is not known which step of the adenomacarcinoma pathway it influences. This case control study investigated the relati on between family history of cancer and colorectal adenomas and cancer s. Family history of colorectal cancer (FHCRC) was as frequent in smal l (<10 mm) adenoma patients (11.7%, n=154) as in polyp free patients ( 10.6%, n=426), whereas it was more frequent in patients with large ade noma(s) (18.8%, n=208; p<0.01). Odds ratios for FHCRC were 1.2 (p>0.10 ) for small adenomas and 2.1 (p<0.01) for large adenomas. Family histo ry of other (non-colorectal) cancers (FHOC) was similar in the three g roups. Patients with a colorectal cancer (n=171) had more frequently a family history of cancer, both colorectal (15.8%; p<0.01) and other c ancers (35.7%; p<0.001) than general population controls (n=309; FHCRC : 8.1%; FHOC: 21.7%). In a logistic model, both factors were independe ntly related to colorectal cancers (odds ratios: 1.9 (p<0.05) for FHCR C and 2.1 (p<0.001) for FHOC). These data suggest that family history of colorectal cancer influences only the growth of adenomas or their m alignant transformation. The finding of a further predisposition to an y type of cancer needs to be confirmed.