Efficacy and tolerance of chemotherapy with dacarbazine or temozolomide associated or not with 5-fluorouracil (5-FU) in endocrine carcinomas: A retrospective multicentric study from the Groupe des Tumeurs Endocrines (GTE)

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Background: Small studies have shown that therapy with dacarbazine and temozolomide give up to 34% tumoral response rates in endocrine carcinomas. The aim of this large retrospective multicentric study was to evaluate efficacy and tolerance of chemotherapy with dacarbazine or temozolomide associated or not with 5-FU in endocrine carcinomas. Methods: Patients were recruited in 6 French and 1 German centers. All patients with well (WDEC) or poorly-differentiated endocrine carcinoma (PDEC), whatever the primary, and who have been treated with dacarbazine or temozolomide associated or not with iv 5-FU or capecitabine, were included. Response rates were evaluated according to RECIST criteria by one of the investigator and toxicity according to National Cancer Institute Common criteria. Results: 86 patients were included : 36 women, median age 61.7 years (27.7 - 85.7), 67 WHO-PS 0–1. Primaries were : pancreas (n=34), digestive tract (n=23), thyroid (n=9), lung (n=6), other (n=6), unknown (n=8). 64 patients had WDEC and 11 PDEC (11 not determined). The number of previous systemic treatments (chemotherapy, chemoembolization, radionuclide therapy) was: 0 (n=16), 1 (n=25), 2 (n=25), 3 (n=14), 4 and more (n=6). Treatments received were : dacarbazine (n=3), temozolomide (n=19), dacarbazine + 5-FU (n=48), temozolomide + capecitabine (n=16). Evaluation was impossible in two patients. Tumoral response rates (partial and stabilization) were 61.2% in WDEC and 18.2% in PDEC. The best response rates in WDEC were : partial response (n=6; 9.7%), stabilization (n=32; 51.6%), progression (n=24; 38.7%) without significant differences between regimens and primary location. Response rates in WDEC were 88.9%, 71.4% and 64.7% in first, second and third line therapies, respectively. Median progression free survival in WDEC was 5.7 months (0.1–41.7). Grade 3–4 toxicities were hematologic (n=8), digestive (n=10), infection (n=3). Conclusions: Dacarbazine and temozolomide therapy showed high partial response and stabilization rates up to 3rd line therapy in well-differentiated endocrine carcinoma, with moderate toxicity. MGMT tumoral status is currently investigated.

No significant financial relationships to disclose.