Forty-five patients with metastatic
neuroendocrine tumors were treated with a regimen of
etoposide 130 mg/m2/d for 3 days plus
cisplatin 45 mg/m2/d on days 2 and 3. Both drugs were given by continuous
intravenous infusion. Among 27 patients with well-differentiated
carcinoid tumors or
islet cell carcinomas, only two partial objective
tumor regressions were observed (7%). Among 18 patients prospectively classified as having anaplastic
neuroendocrine carcinomas, however, there were nine partial regressions and three complete regressions, an overall regression rate of 67%. For anaplastic disease, the median duration of regression was 8 months (range to 21 months).
Tumor response was unrelated to primary site, endocrine hyperfunction, or prior
therapy experience. The median survival of all patients with anaplastic
tumors was 19 months; this seemed favorable when considering the small experiences with these rare
tumors reported in the literature. Toxicity, which was severe for most patients, consisted primarily of
vomiting,
leukopenia,
thrombocytopenia,
anemia,
alopecia, and neuropathy. The anaplastic
neuroendocrine tumor is strongly responsive to
therapy with combined
etoposide and
cisplatin. Patients with
undifferentiated carcinomas, originating in typical
neuroendocrine tumor sites (small and large bowel, pancreas, and stomach) or of unknown origin, who have consistent histologic findings by light microscopy should be evaluated for this possibility with appropriate immune staining or electron microscopy.