Comparison of Gross Tumor Resection Rate between Endoscopic Transsphenoidal Surgery versus Microscopic Transsphenoidal Surgery for Patients with Pituitary Adenomas: A Meta-Analysis

 

Background: Pituitary adenomas are benign lesions originating from the sella and comprise 10% of all brain tumors. Microscopic endonasal-transsphenoidal surgery is a well-established technique to resect symptomatic lesions compressing parasellar neurovascular structures. In recent decades, many skull base centers transitioned to a fully endoscopic transsphenoidal method to address these lesions; proponents suggest panoramic and angled viewing via endoscope allows for greater inspection for residual disease. Whether endoscopic visualization provides superior rates of gross total tumor resection (GTR) over traditional methods remains controversial.

Objective: We conducted a meta-analysis to compare gross total resection (GTR) rates of endoscopic versus microscopic visualization in patients undergoing transsphenoidal surgery (TSS) for pituitary adenomas.

Methods: A meta-analysis of literature was conducted using PubMed, EMBASE, and Cochrane databases through October 2014 for articles evaluating the gross total tumor resection rates of endoscopic (eTSS) versus microscopic (mTSS) visualization methods for TSS for pituitary adenomas (PA). Articles were excluded if they were non-English articles, case reports, systematic reviews, meta-analyses, or if the PAs were resected via craniotomy, combined eTSS and mTSS, or Endoscopic Assistant transsphenoidal surgery (EATSS). Pooled effect estimates of GTR prevalence after TSS were calculated using fixed- and random-effects models.

Results: Thirty-seven case series with 4820 patients which reported gross tumor resection in PAs were included in the final analysis. Twenty-two studies reported GTR for all PA (n = 2460), with an overall GTR of 73.5% (95% CI: 71.6–75.4%; fixed-effects model; I2=90.0%; P-heterogeneity<0.001). Subgroup analysis demonstrated overall GTR was higher in the eTSS group (GTR rate=75.0%; 95% CI: 72.9–77.0%; I2=92.0%; P-heterogeneity<0.001; n = 16) than the mTSS group (GTR rate=66.8%; 95% CI: 61.8–71.5%; I2=52.5%; P-heterogeneity<0.06; n = 6) for all PA (P-interaction=0.36). Fourteen studies reported GTR for Functioning PAs (FPA) (n = 657 patients), with an overall GTR of 72.8% (95% CI: 69.2–76.2%; I2=31.4%; p = 0.13). Subgroup analysis demonstrated GTR was higher in the eTSS group (GTR rate=73.5%; 95% CI: 68.6–77.9%; I2=25.5%; P-heterogeneity=0.22; n = 9) than in the mTSS group (GTR rate=72.0%; 95% CI: 66.4–77.0%; I2=50.1%; P-heterogeneity=0.09; n = 5) for FPA (P-interaction=0.97). Twenty-five studies reported the GTR for Non-Functional PAs (NFPA) (n = 1762), with an overall GTR of 69.3% (95% CI: 66.9–71.7%; I2=87.5%; p < 0.001). Subgroup analysis demonstrated the rate of GTR was higher in the eTSS group (GTR rate=70.4%; 95% CI: 67.6–73.2%; I2=87.0%; P≤0.001; n = 18) than in the mTSS group (GTR rate=66.5%; 95% CI: 61.7–71.0%; I2=89.8%; p < 0.001; n = 7) for NFPA (P-interaction=0.66). Results from the random-effects model were not materially different from the fixed-effects model. While no evidence of publication bias was observed for the GTR rate outcome among patients with non-functional PAs (p = 0.22 for Begg’s test; p = 0.16 for Egger’s test), there was a suggestion of a publication bias among functional PA patients (p = 0.07 for Begg’s test; p = 0.04 for Egger’s test); nevertheless, the trim and fill analysis revealed a pooled effect estimate was not significantly different from the original value (GTR of 70.7% (95% CI: 67.0–74.1%).

Conclusion: Endoscopic transsphenoidal surgery appeared to have a higher efficacy than mTSS in achieving GTR in patients with either functional or nonfunctional pituitary adenoma.