Endocrine Abstracts

Introduction: Treatment of poorly differentiated neuroendocrine tumors (NET) usually includes chemotherapeutic intervention. However, both the rarity and the heterogeneity of the disease have led to relatively few clinical trials. This study evaluated the outcome of two chemotherapy regimens in patients suffering from undifferentiated and histologically confirmed NET.

Methods: Eighteen patients (11 males; age 56.7±2.5) with proven progressive disease were enrolled (mean Ki-67 33.6±4.8%). Patients were treated as follows: from 2005 to 2007 with regimen A (carboplatin, paclitaxel, etoposide)¹; and from 2007 to 2009 with regimen B (cisplatin, etoposide)². This change was due to low tolerability of regimen A. The standard procedure used for imaging-based evaluation was computed tomography, which was performed every 3 months. After chemotherapy, patients were followed up until progression.

Results: Eight patients underwent regimen A (mean 3.3±0.7 courses). Owing to severe side effects (diarrhea, nausea, neurological symptoms) three patients had their therapy prematurely discontinued. The treatment responses of the remaining five patients were: 0% complete response (CR), 20% partial response (PR), 40% stable disease (SD), and 40% progressive disease (PD). The mean progression free survival (PFS) was 6.4±1.2 months (range 3.2–10.0). In contrast, 12 patients were treated with regimen B (mean 3.8±0.4 courses), and none of them dropped out because of side effects. The overall responses were: 0% CR, 17% PR, 33% SD, and 50% PD. The mean PFS was 7.4±2.2 months (range 2.8–26.4). The response rates of both regimes were not statistically different.

Conclusion: Patients who were treated with regimen B demonstrated comparable PFS and less severe side effects than patients who received regimen A. In order to improve therapeutic outcome of patients with progressive undifferentiated NET, new therapeutic approaches are needed.

References: 1. Hainsworth J Clin Oncol 1997.

2. Moertel. Cancer 1991.