Evaluation of the Survival Outcomes of Intestinal Adenosquamous Carcinomas Using the SEER 18 Registry: What Do We Know?

Abstract

Background: Intestinal adenosquamous carcinoma (ASC) is a rare malignancy. This study evaluated overall survival of this malignancy in the small intestine, colon, and rectum. Methods: Using the Surveillance, Epidemiology, and End Results (SEER) 18 registry, we analyzed cases from 2000 through 2015 by Cox proportional hazards using univariate and multivariate analysis, adjusting for age, primary tumor site, tumor grade, and type of surgery performed to calculate the hazard ratios for overall survival. All analyses were performed on R version 4.0.5. Results: We identified 332 patients with ASC: small intestine ( n = 20, 6.02%), colon ( n = 200, 60.2%) and rectum ( n = 112, 33.7%). Age of diagnosis was significantly different between the groups: 44.5, 40, and 36, for small intestine, colon, and rectum, respectively ( p < 0.05). The 5-year survival for small intestine, colon, and rectum were 5.0%, 24.9% and 42.5%, respectively ( p < 0.001). Based on grade of cancer at diagnosis, overall 5-year survival was 61% for 1, 39.9% for 2, 25.9% for 3/4 tumors, and 24.1% for tumors of unknown grade with significant difference ( p = 0.006). The overall hazard ratio in poorly differentiated grade 3 tumors was 3.17 times that of well-differentiated tumors (95% CI, 1.01–9.96, p < 0.05). The overall hazard ratio for death in patients without any surgical intervention was 3.33 (95% CI, 2.34–4.72, p < 0.001) compared to patients who had surgery. Conclusion: There was high rate of diagnosis in advanced stages of ASC, which was associated with poor survival outcomes. Patients who underwent surgical intervention had better survival outcomes when adjusted for grade and site of tumor.