Experience with radiosurgery used in patients with Cushing's syndrome without detected pituitary adenoma

Abstract

Magnetic resonance imaging (MRI) has indicated that about 30% of patients with Cushing's disease (CD) are detected to have no pituitary adenoma despite the hormonal findings suggesting the central genesis of hypercorticism. Choice of treatment policy of such patients remains ambiguous all over the world. In Russia, the Endocrinology Research Center uses the radiosurgical techniques to irradiate the pituitary, by applying a proton beam. The efficiency of pituitary proton irradiation was evaluated in CD patients with undetectable MRI cdenopituitary focal changes versus those with detectable pituitary adenoma. A comparison was made in 2 groups of patients without pituitary adenoma, as evidenced by MRI (Group I; n = 59) and those with identified pituitary adenoma (Group 2; n = 66) who received proton therapy in 1997 to 2002. Clinical improvement was achieved in 88.6 and 95.9% of Groups 1 and 2 patients, respectively; a complete clinical and hormonal remission was observed in 81.8% in Group 1 and in 70% in Group 2. A relapse was recorded in two patients from Group 2 (during a 5-year follow-up). The study has demonstrated that proton therapy for CD is a highly effective and adequate treatment. \\Ъеп MRI detects only the diffuse ambiguous structure of the adenopituitary or the normal structure of the pituitary without signs of focal changes, proton therapy is an alternative to subtotal hypophysectomy.