Clinicopathological features of colon polyps from African-Americans

Among the ethnic groups, the age-standardized incidence rate of colorectal cancer (CRC) is highest among African-Americans. The majority of CRC arise from preexisting adenoma. It is shown that 30% of the US adult population has adenomas. The potential risk of malignant transformation in adenomas differs by specific pathologic and clinical characteristics that we aimed to study in AAs.

All pathologic reports (150,000) in Howard University Hospital from 1959 to 2006 were reviewed manually. Those pathology reports compatible with the colorectal polyps were carefully reviewed and selected by a GI pathologist. All cases with cancer were then excluded from the list. Data were then entered into Microsoft Excel and checked for missing data and duplications. Differences in right-side and left-side polyps for sex, histology, and clinical symptoms were assessed by Chi-2 test.

A total number of 5,013 colorectal polyps were diagnosed in this period that include 47% male, with mean age (SD) of 63 (12). Half of the cases were diagnosed in 2001-2006. Tubular adenoma was the most frequent pathology (73%). The highest frequency of right-sided polyps was observed in the 1990s (56%). Left-sided polyps were younger (p < 0.0001), more hyperplasic (23 vs. 5%; p < 0.0001), and more frequent in female (56 vs. 52%; p = 0.02) compared to right-sided polyps. The frequency of right-sided adenoma significantly increases from 18% in the 1960s to 51% in the period of 2001-2006 (p < 0.0001). The most frequent symptom in both sides was GI bleeding (21%).

There was a ratio of 8:1 for neoplastic to hyperplastic polyps in our study, which is more than what has been reported in Caucasians (7:1). Our data shows a shift in polyps from the left side to the right side of the colon in recent years. This data is consistent with the lack of a reduction in the incidence of colon cancer in African-Americans. Screening is thus very important in AA to reduce the incidence of colon cancer.