Colorectal cancer in a multi-ethnic urban group: its anatomical and age profile

To determine the age of presentation and anatomical distribution of colorectal cancer in an urban multi-ethnic group.

Patients with colorectal adenocarcinoma from 1976-1995 in the tumor registry file of a major hospital in New York City's borough of Manhattan were identified. The charts of 688 patients were reviewed and the location of the cancer, ethnicity, and age at diagnosis were recorded. The tumors were classified as: right cancers (RC); from the cecum, to and including the hepatic flexure, transverse (Trans); left cancers (LC): from the splenic flexure down to and including the sigmoid colon, rectum (Rec); rectosigmoid and rectal lesions; and colorectal lesions without known locations (CA). Patients were classified from self identification, place of birth, or race as: Asians (AS); blacks (BL); Hispanics (HI); and white (WH). An ANOVA test, and a Schefee post hoc test were used to compare the mean ages. While a chi2 and a fully saturated log-linear model compared the proportions.

We could not identify the ethnicity of three patients, and they were not included in the analysis. There were 295 women and 390 men, with a mean age of 66.6 years and 65.0 years, respectively. The overall mean age was 65.7 years. The ethnicity of the patients were: AS = 102, BL = 98, HI = 189, and WH = 296. The mean ages for the different groups were: AS = 59.9 years, BL = 63.5 years, HI = 60.4 years, and WH = 71.7 years. The age difference was significant (P < 0.05), when comparing WH versus each other group. The regional distribution of the individual groups was: AS, RC = 28, Trans = 3, LC = 31, Rec = 37, CA = 3; BL, RC = 40, Trans = 2, LC = 33, Rec = 22, CA = 1; HI, RC = 45, Trans = 3, LC = 71, Rec = 61, CA = 9; and WH, RC = 76, Trans = 19, LC = 95, Rec = 89, CA = 17. The interethnical regional distribution of the cancers was significantly different (P < 0.05). Blacks had a greater presentation of right-sided lesions than expected, and whites had less Rec and RC lesions than expected.

Minority Americans presented with colorectal cancer at a significantly earlier age than WH Americans. Blacks had a high frequency of proximal lesions, and Caucasian Americans had low presentation of RC and Rec lesions. These findings may prove helpful in deciding when to begin screening for colorectal cancer among the different ethnic groups, and what modalities to apply given the differences in anatomical distribution of this cancer.