Background: There are great differences in incidence and prognosis of cancer among the component sites of the digestive tract. Furthermore, a number of the histologic types of tumors at these sites differ in their incidence and prognosis.
Methods: The SEER data from 1973 to 1987 on frequency, incidence, staging, and survival for the various histologic types of 194,452 cancers of the esophagus, stomach, and intestines were studied.
Results: There was an increased incidence of adenocarcinomas of esophagus, gastric cardia, small intestine, and colon; incidence rates for rectal adenocarcinoma and esophageal squamous cell carcinoma remained stable; and rates for gastric adenocarcinoma decreased. Blacks had higher incidence rates than whites for gastric adenocarcinoma; squamous cell carcinoma of the esophagus; carcinoids of the small intestine, colon, and rectum; and gastric sarcomas. Whites, especially males, had higher incidence rates for adenocarcinomas of the esophagus and gastric cardia than did blacks. Blacks had lower rates for rectal adenocarcinomas than did whites, but slightly higher rates than whites for rectal mucinous carcinomas and colonic adenocarcinomas. Data on race, sex, survival, and time trends indicate that mucinous colorectal carcinomas are biologically different from other adenocarcinomas. Males had poorer overall survival than did females for most histologic types of digestive tract tumors. Appendiceal mucinous adenocarcinomas with distant metastases were associated with a high (50%) 5-year survival. The poor prognosis of cases diagnosed as colonic carcinoid raises the possibility that some of these actually may be carcinomas.
Conclusion: Studies of digestive tract cancer require analysis by histologic type for adequate assessment.