Is CO 2 laser microsurgery better than radiotherapy in early glottic cancer: a meta-analysis

The choice between radiotherapy (RT) and CO 2 laser surgery (CO 2 -LS) for early glottic cancer remains controversial. We systematically examined electronic databases in order to identify prospective trials comparing patients who had undergone CO 2 -LS or RT to treat early glottic cancer. Eleven studies involving 1053 patients were included. In the selected literature, the parameter setting of CO 2 laser equipment can be summarized as wavelength 10.6 µm, superpulsed mode, continuous setting, power tailored on target structures (1–3 W for subtle resections and 4–15 W for cutting a larger tumor), and approximately 2080–3900 W/cm 2 of laser energy. Using RevMan 5.3, we estimated pooled odds ratios (ORs) for dichotomous variables and pooled mean differences (MDs) for continuous variables, along with associated 95% confidence intervals (CIs). The heterogeneity in the treatment variables was measured using Higgins’ inconsistency test and expressed as I 2 values. The continuous variables were then depicted as histograms developed using PlotDigitizer 2.6.8. Compared to patients treated with CO 2 -LS, those treated with RT had better jitter (MD 1.27%, 95% CI 1.21 ~ 1.32, P < 0.001), and high scores on the “Grade (MD 6.54, 95% CI 5.31 ~ 7.76, P < 0.001), Breathiness (MD 9.08, 95% CI 4.02 ~ 14.13, P < 0.001), Asthenia (MD 2.13, 95% CI 0.29 ~ 3.98, P = 0.02), and Strain (MD 3.32, 95% CI 0.57 ~ 6.07, P = 0.02)” scale. Patients treated with CO 2 -LS had worse local control rates (OR 3.14, 95% CI 1.52 ~ 6.48, P = 0.002) while lower incidence of second primary tumor (OR 0.30, 95% CI 0.15 ~ 0.61, P < 0.001). It is hoped that retrospective analysis can provide suggestions for early glottis patients to choose personalized treatment.