Abstract 246P
Background
Neuroendocrine carcinoma (NEC) is classified as a highly aggressive, poorly differentiated Grade 3 (G3) tumor, marked by significant nuclear and cellular atypia with Ki-67 indices exceeding 20%. While most of these aggressive cases are lung neuroendocrine carcinomas, extrapulmonary NECs are rarer and less well-documented. Typically, treatment for these tumors involves a regimen of etoposide and platinum chemotherapy. Inspired by the positive outcomes from the IMpower133 study, which demonstrated significant survival benefits with atezolizumab combined with chemotherapy in the first-line treatment of extensive-stage small-cell lung cancer, this study aims to assess the efficacy of atezolizumab combined with platinum and etoposide in treating extrapulmonary NEC, exploring whether these notable benefits can be replicated in this distinct patient group.
Methods
This retrospective cohort study was conducted at Taipei Veterans General Hospital, Taiwan, from January 2016 to June 2023. We compared the efficacy of atezolizumab combined with platinum and etoposide against standard chemotherapy alone in patients diagnosed with extrapulmonary NEC. Outcome measures included response rate, progression-free survival, and overall survival.
Results
The study evaluated 56 patients, with 14 receiving atezolizumab combined with platinum and etoposide (EP) and 42 treated with EP alone. Across the entire cohort, the median PFS was 5.2 months, and the median OS was 11.9 months. No significant differences in OS or PFS between the two treatment groups. Additionally, a neutrophil-lymphocyte ratio (NLR) greater than 3 was identified as a poor prognostic marker for overall survival.
Conclusions
The addition of atezolizumab to etoposide and platinum did not demonstrate a significant improvement in survival outcomes for patients with extrapulmonary NEC, compared to chemotherapy alone. Additionally, a NLR greater than 3 at diagnosis was identified as a poor prognostic marker for overall survival.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.