National trends in the presentation of surgically resected appendiceal adenocarcinoma over a decade

Background: Rates of nonoperative management of acute appendicitis and appendiceal adenocarcinoma have increased over a decade, but the presentation and outcomes of appendiceal adenocarcinoma over this period is not well-characterized. Methods: Patients with surgically resected Stage I–III appendiceal adenocarcinoma were identified from the 2006 to 2015 National Cancer Data Base and classified into two cohorts, 2006–2010 and 2011–2015, based on year of diagnosis. Three-year overall survival (OS) was analyzed using Cox proportional hazards regression and Kaplan–Meier survival estimates. Results: Of 4233 patients, 1369 (32.3%) and 2864 (67.7%) were diagnosed in 2006–2010 and 2011–2015, respectively. Following multivariable analysis, patients in 2011–2015 were more likely to be <40 years of age (6.4% vs. 4.7%, odds ratio [OR] 1.53, p.015), present with pT4 tumors (40.2% vs. 34.4%, OR 1.46, p.004), and undergo hyperthermic intraperitoneal chemotherapy (4.4% vs. 2.4%, OR 1.97, p.001). Comparing patients diagnosed in 2011–2015 to 2006–2010, adjusted 3-year OS was no different among all patients (81.1% vs. 79%, p.778). Conclusions: There has been an increase in the proportion of patients with pT4 appendix tumors over time, primarily among older (≥60 years) patients. Even so, these shifts in presentation have not resulted in differences in survival outcomes.