Transoral robotic versus laser surgery for cT1-T3 supraglottic laryngeal cancers: a systematic review and meta-analysis of comparative and non-comparative studies

Background: To compare literature findings about functional, oncological and surgical outcomes of transoral robotic (TORS) versus transoral laser microsurgery (TOLM) for supraglottic cT1-T3 laryngeal cancers. Methods: Three independent investigators conducted a PubMed, Scopus, and Cochrane Library search for papers reporting oncological, functional and surgical (complications) outcomes of TOLM and TORS. Outcomes were statistically compared considering controlled (direct) studies, and indirectly between single-arm cohort studies. Results: Fifty studies (2,644 patients) were included: 19 single-arm TORS (n = 615), 27 single-arm TOLM (n = 1,122), and four comparative studies (n = 907). Pooled positive margins were 7.3% (95%CI, 4.3-12.0) after TORS and 12.7% (8.6-18.3) after TOLM (P = 0.08); the comparative meta-analysis yielded a risk ratio of 0.65 (0.21-1.99; P = 0.45), also favoring TORS non-significantly. No difference was found for postoperative hemorrhage (5.8% versus 6.4%; P = 0.79) or permanent gastrostomy (7.4% versus 4.8%; P = 0.33). Permanent tracheostomy was rare in both groups (1.6% versus 1.3%), and laryngeal preservation reached 99.6% and 93.0%, respectively. Complication rates were not poolable for TOLM (I2 = 87.0%) owing to definitional heterogeneity. Five-year overall survival was 72.6% (65.8-78.4) in the TOLM series and not poolable for TORS. Median follow-up was 26 versus 50 months. Conclusion: TORS and TOLM provide currently comparable oncological, surgical, and functional outcomes in cT1-T3 supraglottic LSCC. Direct and indirect evidence converged toward a non-significant margin advantage for TORS. Apparent differences across the literature more plausibly reflect case mix, era, follow-up duration, and outcome definitions than the surgical technique itself. Randomized comparisons in matched populations are critically needed.