Outcomes of surgical treatment for nonfunctioning pituitary adenomas: A systematic review and meta-analysis

Background: Surgery is commonly used in the management of pituitary nonfunctioning adenomas (NFPA). The goal of this systematic review and meta-analysis is to evaluate the effect of surgery on mortality, surgical complications, pituitary function and vision. Methods: We searched MEDLINE, EMBASE and Cochrane CENTRAL, queried experts and reviewed the reference list of included publications. Eligible studies were comparative and noncomparative longitudinal studies that enroled patients with NFPA who underwent surgery (alone or in combination with other therapies). Reviewers, working independently and in duplicate, determined study eligibility with adequate reproducibility and extracted descriptive, quality and outcome data. Risks, relative risks (RR) and 95% confidence intervals (CIs) were estimated from each study and pooled using random-effects meta-analysis. Results: Most included studies were uncontrolled case series in which patients received a combination of surgery and radiotherapy. The overall quality of the evidence was very low. Median follow-up was 4·29 years. When surgery was not combined with radiotherapy, there was an increased risk of tumour recurrence (RR 1·97; 95% CI, 1·15-3·35). Complications were more likely with the transcranial than with the transsphenoidal approach (mortality RR 4·89; 95% CI, 3·15-6·47; new anterior pituitary deficits RR 4·90; 95% CI, 2·94-7·82; and persistent diabetes insipidus RR 2·50; 95% CI, 1·05-5·35). Overall, transsphenoidal surgery had fairly low perioperative mortality (≤1%) and low complication rate (≤5% for all patient-important outcomes), but only less than a third of the patients had improvement in pituitary function. Conclusions: Observational evidence supports the association between a combined approach of transsphenoidal surgery with radiotherapy and improvements in visual field defects and reduction in tumour recurrence.