Despite enrichment of high-risk patients (Ki-67 > 55% in 66.7% of patients) in our real-life cohort, the median TTF of 4.9 months (95% CI 3.4–6.4) with first-line therapy was in the range of PFS results reported for the control arms of recent phase III studies in SCLC (Horn et al. 2018; Paz-Ares et al. 2019), which is generally used as reference entity for the very rare GEP-NEN G3. This evidence concerns the gene MKI67 and small cell lung carcinoma.