Advances in chemotherapy and biotherapy of endocrine tumors.

Chemotherapy was considered the standard for treatment of neuroendocrine tumors during the 1970s and 1980s. During the 1980s both interferon alfa and somatostatin analogue therapies were developed and significantly improved the clinical management of malignant neuroendocrine tumors. Surgery remains the cornerstone of treatment and should always be considered in patients with neuroendocrine tumors, even if a cure is not possible. Tumor reduction is always of beneficial value for patients undergoing medical treatment. Since the introduction of biotherapy, no real breakthrough in medical treatment has come forward, but new insights into tumor biology will probably improve therapeutic regimens in the near future. Somatostatin subtype receptor determination in tumor tissues and development of subtype-specific analogues for therapy are two new approaches. The gene for multiple neoplasia type I was cloned recently, and it will increase our understanding of the development of neuroendocrine tumors and give new insights into tumor pathophysiology. The current medical treatment of neuroendocrine tumors is based on chemotherapy for the more highly proliferating tumors, such as malignant endocrine pancreatic tumors and foregut carcinoids, whereas biotherapy, including interferon alfa and somatostatin analogues, is used in slow-growing neoplasms such as midgut carcinoids. These treatments can be supplemented by liver embolizations and chemoembolization to reduce the masses in the liver. When these treatments fail, tumor-targeted irradiation can be attempted, such as 131I-MIBG (metaiodobenzylguanidine) and 90Y DOTA (1,4,7,10-tetraazacyclododecane-N,N(I),N(II),N(III)-tetraacetic acid)-octreotide. The treatment of neuroendocrine gut and pancreatic tumors necessitates a multimodal approach, and more effective medical treatment is being developed.