Background
Retrospective registry study. 305 patients with advanced gastrointestinal neuroendocrine carcinoma (GI-NEC, WHO G3, Ki-67 >20%) diagnosed 2000–2009, retrospectively registered at 12 Nordic hospitals. GI-NEC is a poorly differentiated, aggressive malignancy historically treated with cisplatin+etoposide regimens extrapolated from small-cell lung cancer. NORDIC NEC was the first large-scale analysis of outcomes and predictive/prognostic factors in this rare entity.
Interventions and follow up
Regimen: Platinum-based chemotherapy (cisplatin/carboplatin + etoposide, or oxaliplatin/irinotecan-based regimens) — retrospective registry of advanced gastroenteropancreatic NEC, Nordic centres 2000–2009
Primary endpoint: Overall survival; secondary: response rate, PFS, prognostic factors
Median follow-up: NR (retrospective study; diagnosis 2000–2009)
Primary endpoint: Overall survival; secondary: response rate, PFS, prognostic factors
Median follow-up: NR (retrospective study; diagnosis 2000–2009)
Results
mOS (chemotherapy cohort): 11 months
mOS (BSC cohort): 1 month
ORR (first-line chemo): 31%
Stable disease rate: 33%
Ki-67 <55% — ORR: 15% vs 42% (Ki-67 ≥55%), P<.001
Ki-67 <55% — mOS: 14 vs 10 months, P<.001
Platinum schedule (EP vs oxaliplatin): Did not significantly affect response rate or survival
mOS (BSC cohort): 1 month
ORR (first-line chemo): 31%
Stable disease rate: 33%
Ki-67 <55% — ORR: 15% vs 42% (Ki-67 ≥55%), P<.001
Ki-67 <55% — mOS: 14 vs 10 months, P<.001
Platinum schedule (EP vs oxaliplatin): Did not significantly affect response rate or survival
Adverse events
Overall: Not systematically reported (retrospective registry); toxicities managed per institutional standards.
Expected platinum/etoposide toxicities: Myelosuppression, nephrotoxicity, nausea/vomiting, and peripheral neuropathy.
Expected platinum/etoposide toxicities: Myelosuppression, nephrotoxicity, nausea/vomiting, and peripheral neuropathy.
Conclusions
Platinum-based chemotherapy prolongs survival dramatically versus BSC in advanced GI-NEC (11 vs 1 month). Ki-67 is simultaneously predictive and prognostic: patients with Ki-67 <55% respond poorly to platinum-based chemotherapy but have longer survival, suggesting important biological heterogeneity within the WHO G3 category. Poor PS, colorectal primary site, and elevated LDH/platelets are independent negative prognostic factors. Platinum schedule did not influence outcomes, providing some flexibility in regimen choice.
Key Limitations
Key Limitations: Retrospective registry design with selection and treatment-allocation bias (the BSC cohort was inherently sicker, exaggerating the apparent chemotherapy benefit). Heterogeneous regimens, doses, and supportive care across 12 centers over a decade. No central pathology review; Ki-67 cutoffs were derived post hoc. Adverse-event capture was incomplete. Diagnosis era (2000–2009) predates current WHO NEC/NET-G3 distinctions.
Clinical Context
NORDIC NEC shaped the modern approach to GI-NEC, establishing platinum/etoposide as first-line therapy and identifying the Ki-67 55% threshold that informs the WHO distinction between well-differentiated NET-G3 and poorly differentiated NEC. ENETS and NANETS guidelines incorporate this distinction: NET-G3 tumors (lower Ki-67) often respond poorly to platinum and may be considered for temozolomide-based or NET-directed therapy, whereas true NEC is treated with platinum/etoposide.