Background: Little is known about the epidemiology of rectal carcinoids in the United States since the implementation of screening colonoscopy.
Objective: The goal of this study was to identify epidemiological differences between rectal and small intestinal carcinoids.
Design: This study was retrospective in design.
Setting: Surveillance, Epidemiology and End Results registry data from 1992 to 2008 were examined.
Patients: Patients with rectal carcinoids included those with carcinoid tumors of the rectum. Patients with small intestinal carcinoids included those with carcinoids in the duodenum, jejunum, or ileum.
Main outcome measure: Epidemiological characteristics of rectal carcinoids were identified and compared with small intestinal carcinoids using multiple variable logistic regression.
Results: Patients with rectal carcinoids were more likely to be women (OR, 1.196 (95% CI, 1.090-1.311); p < 0.001). Rectal carcinoids were more common among all minorities, including Asians (OR, 10.063 (95% CI, 8.330-12.157); p < 0.001), blacks (OR, 1.994 (95% CI, 1.770-2.246); p < 0.001), and Hispanics (OR, 2.682 (95% CI, 2.291-3.141), p < 0.001). Patients in the 50- to 59-year age group (OR, 0.752 (95% CI, 0.599-0.944); p = 0.014) were more likely to be diagnosed with rectal carcinoids than those in the 60- to 69-year (OR, 0.481 (95% CI, 0.383-0.605); p < 0.001) and ≥70-year age groups (OR, 0.220 (95% CI, 0.175-0.277); p < 0.001). Rectal carcinoids were more likely to be diagnosed in the screening colonoscopy era among the 50- to 59-year age group (OR, 1.432 (95% CI, 1.082-1.895); p = 0.012). Since the implementation of screening colonoscopy in 2000, the proportion of patients diagnosed with rectal carcinoids has been greater than the proportion diagnosed with small intestinal carcinoids in every year except 2001, and the proportion of patients diagnosed with rectal carcinoids after 2000 has been greater than the proportion diagnosed with small intestinal carcinoids in 12 of 13 Surveillance, Epidemiology, and End Results registry reporting agencies.
Conclusions: Rectal carcinoids and small intestinal carcinoids are epidemiologically distinct tumors with unique presentations. In the era of screening colonoscopy, rectal carcinoids are the more common tumor.