Prognostic validity of AJCC staging system in neuroendocrine tumors of the appendix

Background

Neuroendocrine tumors (NETs) are the most common appendiceal tumors and can be categorized as well-differentiated NETs (WDNETs) and mixed adenoneuroendocrine tumors (MANECs). Currently, WDNETs are classified based on the American Joint Committee on Cancer (AJCC) staging (seventh edition), first proposed in 2010 or according to the European Neuroendocrine Tumor Society staging systems (ENETS). Both systems differ slightly in the T stage. MANECs, which are more aggressive, are staged according to AJCC staging for appendiceal adenocarcinomas. However, the prognostic value of AJCC staging system in WDNETs and MANECs has not been validated.

Methods

Patients (pts) diagnosed with appendiceal WDNET and MANEC (between 1988-2012) in the Surveillance, Epidemiology and End Results (SEER) program were assigned stages I-IV according ENETS (WDNETs only) or AJCC 7th edition (WDNETs and MANECs). Kaplan-Meier method and univariate Cox model were used to evaluate overall survival (OS) and differences in OS across stages, respectively.

Results

We identified 860 and 1173 pts with WDNET and MANEC, respectively. The 10-year survival rates for WDNETs according to ENETS stages I-IV were 96%, 95%, 92%, and 55%, respectively (P 

Conclusions

For WDNET, stage IV is associated with worse survival in both the AJCC and ENETS classifications. In MANEC, both stages III and IV are associated with worse survival.

Clinical trial identification

Legal entity responsible for the study

Dr. Amir Mehrvarz Sarshekeh, Dr. Arvind Dasari

Funding

The University of Texas MD Anderson Cancer Center

Disclosure

All authors have declared no conflicts of interest.