T1a and T1b glottic squamous cell carcinoma (SCC) are often analyzed together by authors who investigate the oncologic outcomes achieved after different therapeutic options. Nevertheless, T1b definitely represents a more advanced tumor stage compared to T1a glottic SCC. The objective of this review was first to analyze the overall success rates in the treatment of patients affected by T1b glottic SCC. Moreover, a subgroup analysis was planned to specifically compare the outcomes obtained with radiotherapy (RT), transoral laser microsurgery (TLM) and open partial laryngectomies (OPL). An electronic library search of the relevant English literature was performed. Potentially eligible articles were reviewed. Qualified articles were selected and evaluated. Fifty-two studies comprising 2360 patients were included. The overall rate of disease-free survival (DFS) was 85% (95% CI 83-87). The overall rate of overall survival was 85% (95% CI 80-88) while the rate of disease-specific survival (DSS) was found to be 96% (95% CI 90-98). Statistical data concerning outcomes for each therapeutic modality showed an higher DFS rate for subjects treated with RT and OPL, respectively, 87% (95% CI 0.85-0.89) and 83% (95% CI 0.78-0.89), when compared to those who underwent TLM 77% (95% CI 0.69-0.83). In conclusion, our results showed a high level of overall DSS (96%) for patients affected by T1b glottic SCC. Regarding the specific therapeutic options, our subgroup analysis showed as patients treated with TLM present a higher rate of oncological recurrence in comparison to those who underwent RT or OPL. Nevertheless, on the basis of our data it was also noted that no significant differences subsist in terms of survival rates among the three different treatments. Moreover, the absence of a comparative analysis useful to confirm these conclusions must be considered.
Keywords: Early glottic cancer; Open partial laryngectomy; Radiotherapy; T1b glottic cancer; Transoral laser microsurgery.