Abstract 50P
Background
Extrapulmonary neuroendocrine carcinomas (EP-NEC) of different localizations have different genetic characteristics and potentially varying sensitivities to chemo- and immunotherapy. Combination of chemo- and immunotherapy showed durable response in 12% of patients with small-cell lung carcinoma but data about efficacy of this approach in treatment EP-NECs are poor. Thus the aim of this study to collect further data about the efficacy this approach.
Methods
This retrospective, single-center study included patients (pts) ≥18 y.o. with histologically confirmed advanced EP-NEC who received at least 1 cycle of combination platinum-based chemotherapy and immunotherapy from May 2019 to April 2024.
Results
The study included 20 pts, 13 male and 7 female. Primary tumor sites were gastrointestinal – 12 (60%) pts (4 pancreatic, 4 colorectal, 4 other site), head and neck – 4 (20%) pts, urology – 3 (15%), cervical – 1(5%). 16 pts (80%) and 4 (20%) had small-cell and large-cell NECs, retrospectively. The median ki-67 was 85% (60-99%). All pts had IV stage of disease. The most common sites of metastases were liver – 12 (60%), distant lymph nodes – 10 (50%) and bones – 5 (20%). One pts had stable brain metastases after SRT. ECOG status was evaluated as 0-1 in 19 (95%) cases. Majority of pts (N=15, 75%) received chemotherapy – EC, 3 pts (15%) – EP, 1 pts FOLFOX and IP. The median number of chemotherapy cycles was 6 (4-8). All pts received anti-PD-L1 therapy, 19 (95%) – atezolizumab and 1 durvalumab. Majority of pts received treatment as first line – 18 (90%). Objective response rate was 35% (N=7/20), disease control rate ≥ 6 months – 55% (N=11). With a median follow-up of 13.7 months, median PFS was 6.2 months (95% CI 4.8-7.7), median OS was not reached (14.8-NR). 4 pts (20%) had a durable response ≥ 12 months, 3 (15%) of them without disease progression at the time of data analysis.
Conclusions
Combination of chemo- and immunotherapy of EP-NECs showed the same median of PFS, ORR with platinum-based chemotherapy but 20% of pts had durable response (≥ 12 months) which is the same with NICE-NEC trial. Further evaluation of the efficacy of combination chemo- and immunotherapy for extrapulmonary NECs is needed in a prospective study with the optimal primary endpoint – 1-year PFS.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Y.A. Zhulikov.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.