ABSTRACT
The choice between radiotherapy (RT) and CO2 laser surgery (CO2-LS) for early glottic cancer remains controversial. We systematically examined electronic databases in order to identify prospective trials comparing patients who had undergone CO2-LS or RT to treat early glottic cancer. Eleven studies involving 1053 patients were included. In the selected literature, the parameter setting of CO2 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/cm2 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 I2 values. The continuous variables were then depicted as histograms developed using PlotDigitizer 2.6.8. Compared to patients treated with CO2-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 CO2-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.