Effects Of Gamma Knife Treatment On The Level Of Endocrine In Patients With Pituitary Prolactinomas

Background:Pituitary adenomas are common intracranial benign tumors derived from the adenohypophysis with an incidence of 1×10-5, whose incidence rate of Chinese people is slightly lower than that of foreigner. Pituitary adenoma, which only shows lower incidence rate than glioma and meningeoma, accounts for about 15-20% of all the intracranial neoplasm. Pituitary adenomas are mainly functional ones, accounting for about 70%. This disease is more common in adults, especially in women. Prolactinoma are the most common functional pituitary adenoma, accounting for 40-60%.Gamma knife treatment is a primary stereotactic radiosurgery technology with such characteristics as achieving its treatment effects through small cluster, single large dosage of focused irradiation into the intracranial lesions; while conventional craniotomy is traumatic and conventional radiation required repeated exposure. Gamma knife treatment was suggested as early as 1951, and it was developed and improved very fast. We used the third generation of Gamma knife (Maxi Pu MASEP-SRRS) in this study.Gamma knife treatment used in treating functional pituitary adenomas was begun in the early 1970 and Bucklund initially employed this technique only in treating patients with Cushing's syndrome. With the development of medicine, more and more patients with pituitary adenomas receivedγ-knife treatment. The greatest features are no risk of traumatic surgery and anesthesia, few reported optic nerve injury and low mortality rate. Patients with pituitary adenomas may suffer from both such neurological impairments as vision loss or blindness and oppression of the brain stem or hypothalamus, and reproductive, developmental, metabolic, cardiovascular and other organ dysfunctions resulting from the oppression of optic nerves and abnormal secretion of hormones, respectively. Without active treatment, the mortality rate is very high. Therefore, for patients with functional pituitary adenomas, especially pituitary prolactinoma, solutions on the oppression of optic nerves and abnormal secretion of hormones ask for more attentions.Objective:To analyze the effects of y-knife treatment with different dosages on the level of prolactin (PRL) in patients with different sizes of functional pituitary prolactinomas. We also aimed at determining an index to guide hormone replacement therapy and prognosis ofγ-knife treatment in patients with functional pituitary prolactinomas through comparing the changes of the tumor sizes and the levels of PRL before and after theγ-knife treatment.Methods:A retrospective analysis of the clinical data of 248 cases of functional pituitary prolactinomas was performed:gamma knife treatment was performed on these patients from September 2004 to March 2008. We divided the patients into 3 groups:group 1 (50≤central dose< 60 Gy,20< marginal dose< 30 Gy), group 2 (40≤central dose< 50 Gy,15< marginal dose< 25 Gy) and group 3 (30≤central dose< 40 Gy,12< marginal dose< 20 Gy). The irradiation dose on optic nerves in the 3 groups was under 9 Gy.Results:MRI showed 80% partial response rate (198/248) at the 1st y,82% complete response rate (203/248) at the 2nd y, increased volume in 19 and no changes in 26. The level of serum PRL was decreased in 101 patients (40.7%), normal in 90 (36.3%), increased in 20 (8.1%) and unchanged in 37. No significant difference in age and gender of the patients was found (P=0.127 and P=0.204, respectively). Multivariate analysis showed that the high marginal dose and central dose induced significantly normal level of serum PRL (P=0.000).Conclusion: different treatment doses of gamma knife (γ-刀) of functional prolactin (PRL) adenoma has great effect on postoperative recovery of endocrine, the more doses of the center and edge (especially center), the higher normal rate of ostoperative prolactin (PRL). Whether it will cause long-term low power of pituitary need to continue follow-up.