Endocrine Abstracts

It is known that treatment of prolactinomas with dopamine agonists is accompanied by relapses of the disease after discontinuation of the treatment in about 50% of cases and long-term or lifelong medication is required. The aim of the study was to evaluate the effectiveness of surgery in achieving remission or biochemical control of the disease. We prospectively enrolled 32 consecutive patients with prolactinomas who underwent transsphenoidal resection performed by the highly qualified surgeon. We evaluated the invasiveness of prolactinomas on the Knosp grading scale and measured serum prolactin concentrations on the first postoperative day. Routine histological assessment of the Ki-67 proliferation index was performed. The level of PRL was assessed in the early and in the late postoperative periods. Pituitary MRI with contrast enhancement was performed in 3, 6 and 12 months after surgery. Among 32 operated patients 32% achieved complete recovery and met the remission criteria during the entire follow-up period. In all patients who achieved remission, adenomas were noninvasive (Knosp 0, 1) and non-aggressive (Ki-67 <3%). The average level of PRL on the first day after surgery was 295.2 mMEd/l (P>0.1). Biochemical control was achieved in 28%. In this group, 44% had noninvasive adenomas (Knosp 0, 1), 56% had invasive adenomas (Knosp 2,3). Ki-67 was <3% in all removed tumor tissues. The average value of PRL on the first day after surgery was 1244 mMEd/l. A significant reduction in the volume of prolactinomas after surgical resection (more than 80%) made it possible to normalize the level of PRL against the background of lower doses of cabergoline, compared with the doses of the drug taken before surgery. Patients who did not achieve postoperative remission and biochemical control accounted for 40% of the total number of patients. This group consisted of individuals with large (more than 4 cm) and giant (more than 6 cm) invasive tumors (Knosp 3,4). Ki-67 was ≥3%, which corresponded to a high degree of invasiveness and aggressiveness of the tumor. The average value of PRL on the first day after surgery in this group was 19 348±7816 mMEd/l All patients had absolute indications for emergency surgery. Transnasal transsphenoidal adenomectomy leads to complete postoperative remission in 32% of cases and in 28% of cases allows to achieve biochemical control of the disease while taking cabergoline. Radiological assessment of prolactinoma invasiveness and early postoperative serum prolactin concentrations are important predictors of early remission after surgery.