Adenocarcinoma of the small bowel: A 60-yr perspective derived from M. D. Anderson Cancer Center Tumor Registry

OBJECTIVES: To analyze subsite distribution of small bowel adenocarcinoma (SBA) over a 60-yr interval and to determine the impact of age, gender, and ethnicity on SBA cross-referenced for selected variables including anatomic distribution. METHODS: Data from 1944 to 2003 were extracted from the M. D. Anderson Cancer Center Tumor Registry (MDACCTR) and analyzed by age, gender, ethnicity, anatomic site, and time intervals. RESULTS: A total of 523 confirmed cases with 460 specified for subsite were identified. Peak incidence occurred in the sixth decade with male predominance (58%). Relative distribution for subsites was stable over the period of study; however, site-specific incidence differed significantly with age. Although jejunal SBA comprised only 21% of site-specific total (SST), 49% occurred in 0-49 age group rendering duodenal SBA (59% of SST) more common with increasing age (p < 0.001). A higher percentage of women presented at younger age; however, the difference was not significant (p = 0.061). Subsite distribution was similar for both genders, but varied significantly among ethnicities (p = 0.048) with Hispanics and African Americans having a higher percentage of duodenal SBA. The age and gender distribution among ethnicities varied significantly. African Americans having SBA presented at a younger age (p < 0.001), and comprised a higher percentage of women (p = 0.026). CONCLUSION: Differences exist for SBA subsite distribution within age and ethnic groups but not gender. Unlike colon cancer, SBA subsite distribution has been stable during the last six decades. Different risk factors for SBA appear to affect different subsites. Site- and age-related distribution impacts on diagnostic evaluation for SBA.