Clinical and Pathological Analyses of Patients with a Family History of Colorectal Cancer

Patients who were registered by the Japanese Society for Cancerof the Colon and Rectum between 1978 and 1983 were examinedclinically and pathologically, in terms of colorectal cancerwith familial accumulation. The incidence of patients with afamily history of colorectal cancer (FH⁺ group)—patientswith adenomatosis coli were excluded—was 6.5% in 15,369colorectal cancer patients. The incidence of patients with afamily history of malignant tumors other than colorectal cancerwas 27.7%. Comparison of the FH⁺ group with the FH^– group(patients without a family history of colorectal cancer) revealedthe incidence of colonic cancer to be significantly higher thanthat of rectal cancer in the FH⁺ group (P<0.01). The patientswith colonic cancer in the FH⁺ group were significantly youngerthan those in the FH^– group (P<0.01), but there wasno age-dependent difference between patients with rectal cancerin the two groups. There was no difference in sex ratio andthere was little difference in the subsite of the primary lesionin the colon between the FH⁺ and FH^– groups. The incidenceof multiple primary colorectal cancer was significantly higherin patients with colonic cancer in the FH⁺ group than in theFH^– group (P<0.01). The incidence of multiple primarycancer in sites other than the colon and rectum was significantlyhigher in the FH⁺ group (P<0.01), but no significant differencewas found in the site of lesions. The prognosis of patientsin the FH⁺ group was significantly better than that of thosein the FH^– group; however, there were no differences inbackground factors such as findings of the primary lesion, statusof metastasis, clinical stage and rate of curative resectionbetween the groups.