For patients who do not achieve control with SRLs, the GH-receptor antagonist Pegvisomant offers a different mechanism of action. Unlike SRLs, which target the tumor, pegvisomant blocks the GH receptor in the liver, preventing the production of IGF-1. This makes it highly effective at normalizing IGF-1 levels in over 90% of patients, even when GH levels remain high. However, because it does not target the tumor, regular MRI monitoring is required to ensure the adenoma does not continue to grow.

Radiotherapy is typically reserved as a third-line "adjunct" treatment for aggressive or unresectable tumors. It can be delivered via traditional fractionated radiation or "Stereotactic Radiosurgery" (Gamma Knife), which delivers a precise, high-dose beam to the tumor. The Acromegaly Market documentation details the integration of these specialized radiotherapy services within pituitary centers. The primary drawback of radiation is its slow onset of action; it can take 5 to 10 years for hormone levels to normalize, during which time medical therapy must be continued.

The ultimate management of acromegaly is increasingly leaning toward "Precision Medicine," where the choice of therapy is guided by the tumor's genetic and histological characteristics. By combining surgery, multi-modal medical therapy, and targeted radiation, the multidisciplinary "Pituitary Team" aims to restore the patient's life expectancy and quality of life to that of the general population.