Transoral laser microsurgery versus radiotherapy for T2 glottic squamous cell carcinoma: a systematic review of local control outcomes.

BACKGROUND: Systematic reviews comparing treatment of early glottic cancer with transoral surgery or radiotherapy demonstrate similar oncological outcomes. Most studies of 'early-stage' laryngeal cancer include Tis, T1a, T1b and T2 cases. The data are dominated by patients with T1 and Tis tumours, although extrapolating these results and applying them for T2 cases may be inappropriate. No previous systematic reviews have focused on T2 cancers as a separate group.

OBJECTIVE OF REVIEW: This review compares local control outcomes for T2 glottic squamous cell carcinoma, treated with transoral microsurgery or external beam radiotherapy.

TYPE OF REVIEW: This is a systematic review of case series and comparison studies, focusing on oncological outcomes.

SEARCH STRATEGY: Independent searches of MEDLINE, EMBASE and the Cochrane Database were conducted by two authors, using the search terms: laryngeal/glottic/vocal cord combined with carcinoma/cancer/tumour and laser/microsurgery or radiotherapy. Studies of adult patients treated for primary T2N0 glottic squamous cell carcinoma (SCC) with laser surgery or curative radiotherapy were included.

EVALUATION METHOD: Full text of studies satisfying the inclusion criteria were reviewed with extraction of local control and survival data and laryngeal preservation rates. The primary endpoint is local control at 5 years.

RESULTS: Initial searches identified 3252 studies. Following full-text review of 183 papers, 59 studies met the inclusion criteria, all level IV evidence. A total of 48 studies specified 5-year local control for 1156 patients treated with transoral laser surgery and 3191 patients treated with radiotherapy. Weighted averages of local control at 5 years demonstrated similar results: 75.81% for radiotherapy versus 77.26% for transoral laser surgery.

CONCLUSIONS: The results of this review indicate no difference in 5-year local control between radiotherapy and transoral surgery for T2 glottic SCC. The data demonstrated higher rates of local failure for T2b compared with T2a cases, although outcomes were similar between laser excision and radiotherapy for each substage. Further research focusing upon functional outcomes for T2 glottic tumours is imperative to guide decision-making, ideally with subgroup analysis of T2a and T2b cases.