Clinical Effect of Temozolomide-Based Chemotherapy in Poorly Differentiated Endocrine Carcinoma After Progression on First-Line Chemotherapy

BACKGROUND: Patients with metastatic poorly differentiated endocrine carcinoma (PDEC) usually have a short survival. The chemotherapy combination of cisplatin and etoposide is frequently used as first-line palliative chemotherapy. There are, however, no published studies concerning second-line treatment of the disease. Temozolomide has shown clinical effect in well-differentiated endocrine carcinomas. This study was performed to evaluate the effect of temozolomide in PDEC patients who had progressed on first-line treatment. METHODS: Twenty-five patients with PDEC (mainly gastrointestinal) were treated with temozolomide alone or in combination with capecitabine. A subset of patient also received bevacizumab. MGMT methylation was analyzed in tissue specimens. Data were collected retrospectively. RESULTS: One patient had a complete response, and 7 patients had partial response (33% response rate). Median duration of response was 19 months. Another 9 (38%) patients had a stable disease, after progression at inclusion, with a median duration of 18 months. Median progression-free survival for all patients was 6 months, and median overall survival was 22 months. Only 1 patient had a MGMT methylation. CONCLUSIONS: Treatment with temozolomide alone or in combination with capecitabine and bevacizumab resulted in objective response or stabilization in 71% of PDEC patients who failed on first-line chemotherapy. These results indicated that temozolomide may be used as second-line treatment in PDEC. Cancer 2011;117:4617-22. (C) 2011 American Cancer Society.