Pituitary function before and after surgery for nonfunctioning pituitary adenomas - Data from the Swedish Pituitary Register.

OBJECTIVE: Data on pre- and postoperative pituitary function in nonfunctioning pituitary adenomas (NFPA) are not consistent. We aimed to investigate pituitary function before and up to five years after transsphenoidal surgery with emphasis on the hypothalamic-pituitary-adrenal axis (HPA).

DESIGN AND METHODS: Data from the Swedish Pituitary Register was used to analyze anterior pituitary function in 838 patients with NFPA diagnosed between 1991 and 2014. Patients who were reoperated or had received radiotherapy were excluded.

RESULTS: Preoperative ACTH, TSH, LH/FSH and GH deficiencies were reported in 31% (236/755), 39% (300/769), 51% (378/742) and 28% (170/604) of the patients, respectively. Preoperative median tumor volume was 5.0 (2.4-9.0) cm3. Amongst patients with preoperative, one year and five years postoperative data on the HPA axis (n=428), 125 (29%) were ACTH-deficient preoperatively. One year postoperatively, 26% (32/125) of them had recovered ACTH function while 23% (70/303) patients had developed new ACTH deficiency. Thus, one year postoperatively 163 (38%) patients were ACTH-deficient (P <0.001 vs. preoperatively). No further increase was seen five years postoperatively (36%, P=0.096). At one year postoperatively recoveries in the TSH- and LH/FSH-axes were reported in 14% (33/241) and 15% (46/310), respectively, and new deficiencies in 22% (88/403) and 29% (83/288), respectively.

CONCLUSIONS: ACTH deficiency increased significantly at one year postoperatively. Event though not significant, some patients recovered from or developed new deficiency between one and five years postoperatively. This pattern was seen in all axes. Our study emphasizes that continuous individual evaluations are needed during longer follow-up of patients operated for NFPA.