- Tumors of the adrenal gland are common. Most of them are not cancerous. However, there are no tests that can accurately tell which adrenal tumors are cancerous and which are not. The only way to tell is to remove the tumor with surgery and then examine it. Researchers have been using new methods to study samples of adrenal tissue. These methods may help identify whether the cells are or may become cancerous without an operation. This information will help doctors determine which tumors will need to be removed.