Colorectal adenomatous polyps and carcinoma in Ashkenazi and non-Ashkenazi Jews in Israel.

In Israel, the incidence of colorectal cancer among European-American-born Jews is approximately 2.5 times that of African-Asian-born Jews. To determine the risk of all colorectal tumors for the two ethnic groups, 335 patients with colorectal adenomatous polyps and 295 with colorectal cancer, diagnosed between 1980-1984 at the Sheba Medical Center, were compared to the 35,094 persons attending the outpatient clinics at the same hospital, during September and October 1984. Ashkenazi patients (European-American-born) had a 2.5-fold risk (95% confidence interval 1.9-3.3) of colorectal polyps compared to non-Ashkenazi patients (African-Asian-born). The risk was similar for males (odds ratios [OR] = 2.3) and females (OR = 2.8). Ashkenazis also had a significantly enhanced risk of carcinoma: OR = 3.1; 95% confidence interval 2.2-4.3. The risk ratio was slightly higher for males (OR = 3.5) than females (OR = 2.7). Age-specific analyses demonstrated an elevated risk of both malignant and benign neoplasms among Ashkenazi patients at all ages at diagnosis. Among the polyp patients, the highest risk ratio was for patients between 30 and 49 years old, while among the cancer patients the risk was highest in the group of 60-69-year-olds. The distribution by size of polyps, number of polyps, as well as polyp subsite, was similar for Ashkenazi and non-Ashkenazi patients; however non-Ashkenazis tended to have slightly more right-sided colon cancer.