Topotecan Monotherapy in Heavily Pretreated Patients with Progressive Advanced Stage Neuroendocrine Carcinomas

Background: Neuroendocrine carcinomas (WHO grade 3) are highly aggressive tumors with an immense tendency to metastasize and with a poor prognosis. In advanced disease, there is no standard treatment beyond first-line platin/etoposide-based chemotherapy. Topotecan is widely used as second-line treatment in small cell lung cancer, which also responds markedly on first-line platin/etoposide. Hence, we investigated the feasibility of topotecan in previously treated patients with neuroendocrine carcinomas. Material and Methods: Retrospective analysis of 22 patients with disseminated and progressive neuroendocrine carcinomas (Ki67>20%, G3) successively treated with oral topotecan 2.3 mg/m(2) d1-5 every 3 weeks. All patients had previously received treatment with carboplatin/etoposide. Demographic, clinical and pathological features were recorded. CT-evaluations according to RECIST 1.1 were performed after every three courses. Hematological toxicity was assessed by CTC-criteria. Results: Twenty-two eligible patients received a median of 2 courses [range1-6]. Median age: 65 years [35-77]. Male/female: 11/11. Median Ki-67 index: 95% [25-100%]. Median number previous chemotherapy regimens: 2 [1-3]. All patients were evaluable for response: Five achieved stable disease (SD) and 17 progressed (PD). The median overall survival for the 22 patients was 3.2 months and the median progression-free survival was 2.1 months. The one-year survival was 18%. There were no treatment related deaths. The treatment was well tolerated: Haematological toxicity comprised leukopenia CTC grade 3 (14%), grade 4 (9%) and thrombocytopenia grade 3 (14%). Conclusion: Topotecan monotherapy shows modest anti-tumor activity in heavily treated patients with progressive disseminated G3 neuroendocrine carcinomas.