For both NEC (n = 1346) and OCT (n = 1214), significant differences in CSS were found with increasing SEER historic stage (localized, regional and distant, all P < .001), combined 8th AJCC stage (P < .001), and increasing M status (M0 and M1, P < .001). This evidence concerns the gene PLXNA2 and neuroendocrine carcinoma.