Lymph node positivity and association with long-term survival for different histologies of appendiceal cancer

Background: Appendiceal cancers represent a diverse group of malignancies with varying biological behavior. The significance of lymph node metastases in relation to long-term survival and chemotherapy response is poorly defined. Methods: The National Cancer Database was queried to find patients diagnosed with appendiceal cancer from 1998 to 2012. Kaplan–Meier curves and multivariable Cox regression analyses were used to study the association between lymph node status and overall survival. Stage IV patients were excluded. Results: The rate of nodal positivity of the 9841 patients with known node status was: signet ring 47.4%, carcinoid 42.3%, nonmucinous adenocarcinoma 28.8%, goblet cell 21.9%, and mucinous adenocarcinoma 20.4%. Node-positive patients had worse long-term survival for all subtypes with the exception of carcinoid tumors (p < 0.001). The strongest association was for signet cell and goblet cell. Adjuvant chemotherapy in node-positive patients improved survival for mucinous, nonmucinous, and signet ring cell histology (p < 0.01), but not for goblet cell. Conclusions: Nodal involvement in patients with appendiceal cancer varies in incidence, association with adverse survival, and response to systemic therapy. Individualized treatment algorithms for the management of the subtypes of appendiceal cancer are needed.