Impact of cytoreductive surgery on outcomes of metastatic appendiceal carcinoma: a real-world, population-based study.

Abstract

Aim: To evaluate the impact of cytoreductive surgery on the outcomes of patients with metastatic appendiceal carcinoma. Methods: Surveillance, Epidemiology and End Results (SEER) database was accessed and patients with metastatic appendiceal carcinoma diagnosed (2010-2015) were reviewed. Kaplan-Meier survival estimates/log-rank testing were then used to assess overall survival outcomes according to cytoreductive surgery. Multivariable Cox regression analysis was then used to evaluate factors affecting cancer-specific survival. Factors included in this model were age, race, sex, stage and histology and cytoreductive surgery. Results: A total of 1339 patients with metastatic appendiceal carcinoma were included in the current study. Using Kaplan-Meier survival estimates to evaluate overall survival, patients with surgery for metastatic disease have better overall survival compared with patients without surgery for metastatic disease (p < 0.001). Stratifying survival analysis according to histology, the overall survival benefit from surgery for the metastases seems to be limited to patients with mucinous adenocarcinoma (p=0.002) rather than patients with nonmucinous adenocarcinoma (p = 0.401). Multivariable Cox regression analysis was then conducted to evaluate factors predicting cancer-specific survival. The following factors were associated with worse cancer-specific survival: African-American race (hazard ratio [HR]: 1.356; 95% CI: 1.036-1.774; p = 0.026), more advanced stage (HR: 3.910; 95% CI: 2.735-5.588;p < 0.001), nonmucinous adenocarcinoma (HR for signet ring carcinoma vs mucinous adenocarcinoma: 2.119; 95% CI: 1.674-2.683; p < 0.001) and no surgical resection of metastatic disease (HR: 1.273; 95% CI: 1.067-1.519; p < 0.001). Conclusion: The current study suggests that among patients with metastatic appendiceal carcinoma, surgical cytoreduction of metastatic disease is associated with improved outcomes for patients with mucinous adenocarcinoma but not in patients with nonmucinous adenocarcinoma.