Gastroenteric neuroendocrine neoplasms classification: Comparison of prognostic models

BACKGROUND: Gastroenteric neuroendocrine neoplasms (GE-NENs) display highly
variable clinical behavior. In an attempt to assess a better prognostic
description, in 2010, the World Health Organization (WHO) updated its previous
classification, and the European Neuroendocrine Tumors Society (ENETS) proposed a
new grading and TNM-based staging system. In the current study, the authors
evaluated the prognostic significance of these models and compared their efficacy
in describing patients' long-term survival to assess the best prognostic model
currently available for clinicians.
METHODS: The study cohort was composed of 145 patients with extrapancreatic
GE-NEN who were observed from 1986 to 2008 at a single center and were classified
according to the WHO and ENETS classifications. Survival evaluations were
performed using Kaplan-Meyer analyses on 131 patients. Only deaths from neoplasia
were considered. A P value < .05 was considered significant. Prognostic efficacy
was assessed by determining the Harrell concordance index (c-index).
RESULTS: Both the 2010 WHO and the ENETS classification were able to efficiently
divide patients into classes with different prognoses. According to the model
comparison, the ENETS TNM-based staging system appeared to be the strongest. All
combined models were effective prognostic predictors, but the model that included
the 2010 WHO classification plus ENETS staging had a higher c-index.
CONCLUSIONS: Both the 2010 WHO classification and the ENETS staging system are
valid instruments for GE-NENs prognostic assessment, with TNM-based stage
appearing to be the best available choice for clinicians, both alone and in
association with other classifications.