Background: Non-functioning pituitary adenomas (NFPA) account for 30-35% of pituitary adenomas. They can lead to hypopituitarism and visual field defects. Trans-sphenoidal resection of pituitary adenoma remains the treatment of choice.
Methods: We compared clinical, biochemical, and imaging characteristics of NFPAs at presentation with post-surgical outcomes in a retrospective cohort study. Patients who underwent endoscopic trans-sphenoidal resection for a non-functioning pituitary macroadenoma (July 2009 August 2016) were identified and clinical records analysed.
Results: 118 patients with NFPAs were included (64% male, follow-up 3.3±1.8 yrs, age at surgery 59.7±13.6 yrs). Immunohistochemical analysis identified most tumours to be gonadotroph (n=55, 46.6%) or null cell (n=53, 44.9%) adenomas.
At presentation, 52 patients (44%) had normal pituitary function; 47 (39.8%) 12 anterior pituitary axis deficits and 19 (16.1%) ≥3 deficits. Gonadotroph deficiency (43%) was most frequent. Male gender (65% vs. 44%, P=0.0008) and older age (P=0.02) were associated with multiple hormone deficiencies.
Pre-operative tumour volume did not correlate with degree of hypopituitarism (P=0.35, R=0.09). Mean tumour volume reduction after surgical resection was 73.1±23.2%.
At follow-up, the number of patients with hormone deficiencies increased from 55.9% to 66.1% after surgery. Six patients developed permanent diabetes insipidus. Extent of tumour resection was not predictive of new onset hypopituitarism post-operatively (P=0.14). Overall, postoperative hormonal recovery was observed in 14 patients (11.8%), with the greatest recovery occurring in the gonadal axis (57.1%, 8/14).
Thirty-two patients (27.1%) were submitted to radiotherapy whilst 15.3% (n=18) underwent redo-surgery. A large residual tumour volume increased the likelihood for adjuvant radiotherapy (4.25 vs. 1.34 cm3, P=0.04), but was not predictive of need for repeat surgery (P=0.11).
Conclusions: NFPA prevail in males and they are more likely to have multi-hormonal deficits. In our cohort, total/subtotal resection of pituitary adenoma is not a significant risk to pituitary function and it possibly can promote recovery of pre-existing pituitary dysfunction, in particular in gonadal axis.