Clinical management of malignant adrenal tumors

Abstract

Malignant primary adrenal tumors are rare forms of cancer with an estimated incidence of two to ten new cases per one million inhabitants per year. The 5-year survival rate for adrenocortical carcinoma is approximately 35%, whereas the 10-year survival rate of malignant pheochromocytoma reaches 40%. Clinical studies support repeated surgery as the mainstay of treatment, either with curative or palliative intention. For adrenocortical carcinoma, adjunctive treatment with oral mitotane leads to well-documented improvement of survival. Rare malignant pheochromocytomas with distant metastases are preferably treated by 131I-MIBG. Chemotherapy is reserved for unresectable tumors without sufficient response to mitotane or 131I-MIBG, respectively. Cisplatin and etoposide as single therapy, or in combination with doxorubicin or etoposide, appear to be effective in adrenocortical carcinoma. Malignant pheochromocytoma may be treated with vincristine, dacarbazine, and cyclophosphamide. Treatment with octreotide is currently being evaluated. Radiotherapy is indicated if unresectable tumor masses cause local symptoms. If symptoms of endocrine activity are not sufficiently controlled by measures aiming at tumor mass reduction, specific inhibitors of hormone synthesis or action are available. Ketoconazole is widely used for adrenocortical carcinoma, and phenoxybenzamine and metyrosine are available for malignant pheochromocytoma. This review provides guidelines for rational disease management based on still scanty clinical evidence.