Postoperative Radiotherapy in the Treatment of Functioning and Nonfunctioning Pituitary Adenomas: A Systematic Review and Meta-analysis of 3,323 Patients

Objective Although surgery is the mainstay of treatment for most pituitary adenomas, postoperative radiotherapy has been shown to be of benefit in improving tumor control and recurrence-free survival. However, due to the potential complications and long-term side effects associated with radiotherapy, the role of postoperative radiotherapy in the setting of pituitary adenomas remains unclear. To address this gap, we performed a systematic review and meta-analysis to determine the efficacy and safety of postoperative radiotherapy for pituitary adenoma.

Methods A systematic review was performed according to the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. We searched PubMed, MEDLINE, and Cochrane databases with no language or publication date restrictions. Outcomes included 5- and 10-year progression-free survival and adverse event rates. Forest plots were generated to determine a pooled event rate and 95% confidence interval (CI) for each outcome using a random effect model analysis.

Results A total of 48 studies from 1986 to 2016 met the inclusion criteria, with 3,323 cumulative patients. Studies included patients with functioning adenomas only (n = 12), nonfunctioning adenomas only (n = 12), or both (n = 20). The cumulative 5- and 10-year progression-free survival rates were 90.8% (95% CI: 86–94%) and 88.6% (95% CI: 81–93%), respectively. The overall adverse events rate was 8% (95% CI: 5–12%). All outcomes were associated with significant heterogeneity (I2 ≥ 70%). There were no differences in survival rates or adverse events in relation to study date, tumor pathology, radiosurgery system used, or dose of radiation.

Conclusion Postoperative radiotherapy for pituitary adenomas is effective and safe. Because of the significant heterogeneity and lack of matched controls in the literature, optimum timing and dosage are still unclear. Further prospective studies are needed.