Gastroenteropancreatic neuroendocrine tumors (NET)
are an extremely heterogeneous entity with respect to
their biological behavior and functionality. Considering
the diversity of NET, therapeutic approaches should be
chosen carefully. Besides surgical resection or tumor debulking,
various palliative options including medical, locally
ablative and radiotherapeutical interventions are
available. In functionally active tumors biotherapy with
either somatostatin analogues or interferon alpha is indicated.
The results of chemotherapy are often unsatisfactory,
and its use is mostly restricted to pancreatic neuroendocrine
carcinomas. Here, streptozotocin and 5-fluorouracil
or doxorubicin are considered standard first-line
therapy. In slowly progressing disease, however,
chemotherapy is not effective. In rapidly growing carcinomas
etoposide and cisplatin are mostly applied. In the
treatment of hepatic metastases, embolization therapy
with or without chemotherapy is frequently used when
surgery is not an option. Radiofrequency ablation is another
alternative. In tumors with strong somatostatin receptor
expression, radionuclide therapy is an approach
that enables internal radiation therapy. Bearing in mind
actually running active clinical trials, we here present a
therapeutic algorithm which we hope will facilitate therapeutical
decision making.