Pembrolizumab-based systemic therapy associated with opportunities for subsequent local treatment in advanced or recurrent neuroendocrine carcinoma of the cervix: a five-case series

Background: Neuroendocrine carcinoma (NEC) of the cervix is a rare, highly aggressive malignancy with limited evidence supporting immune checkpoint blockade. We evaluated the clinical activity of pembrolizumab-based therapy in patients with advanced or recurrent cervical NEC.
Methods: We retrospectively reviewed five consecutive patients with advanced or recurrent cervical NEC treated with pembrolizumab-based therapy at Okayama University Hospital between November 2022 and April 2025. Clinical characteristics, radiologic responses, molecular profiles, adverse events, local treatments, and survival outcomes were analyzed.
Results: The median age was 52 years. Three patients had newly diagnosed stage IVB disease, and two had recurrent metastatic disease after radical surgery and postoperative irinotecan plus cisplatin chemotherapy. All patients received paclitaxel plus carboplatin with pembrolizumab. An objective response was observed in all patients, including one complete response and four partial responses according to RECIST version 1.1. The median maximum tumor shrinkage was 78.5%, and median progression-free survival was 10.0 months. Comprehensive genomic profiling in four patients showed microsatellite-stable tumors with low tumor mutational burden in all evaluated cases. HPV association was supported by HPV16/18 sequences in three patients and diffuse p16 expression in one additional patient. Immune-related adverse events were grade 2 or lower. In three patients, systemic disease control allowed subsequent local treatment, including radiotherapy, conversion surgery, and stereotactic radiotherapy.
Conclusion: Pembrolizumab-based therapy showed encouraging clinical activity despite microsatellite-stable status and low tumor mutational burden in evaluated cases. Sustained systemic disease control may provide an opportunity for multimodal treatment incorporating subsequent local treatment.