Long-term octreotide treatment of metastatic carcinoid tumor.

The optimal dosage of somatostatin analogs for the long-term control of carcinoid tumors has not yet been established. Receptor alterations induced during long term treatment with somatostatin analogs have lead to consecutive drug dosage increases in order to control carcinoid disease. In this report, we describe the rapid and effective control of tumor in a patient with metastatic carcinoid treated for nine years with a single daily dose of octreotide based on tumor marker levels. Tumoral somatostatin receptor (sst) subtype analysis by RT-PCR amplification showed the expression of sst2 subtype only. We suggest that a single daily dose of octreotide strictly related to tumor marker secretion, could have played a role in the effective long-term therapy by avoiding the phenomenon of somatostatin receptor desensitisation. Furthermore, the exclusive presence of sst2 subtype supports the high affinity of octreotide to tumoral cells.