Assessment of Voice Outcomes Post Chemo-Radiotherapy in Non-Laryngeal Head & Neck Cancers Using Electroglottography and Voice Symptom Scale (VoiSS) Questionnaire.

Background: Laryngeal toxicity (LT) following concurrent chemo-radiotherapy (CCRT) for non-laryngeal head & neck cancers(NLHNC) has been inadequately studied. Electroglottography (EGG), a non-invasive technique for objective quantification of LT, measures the change in electrical impedance generated by glottic closure.

Aim: Objective and subjective assessment of acute LT post-CCRT in NLHNC.

Materials and methods: A prospective study on 30 NLHNC patients, treated with CCRT; 66-70Gy/33- 35fractions with weekly Cisplatin. Flexible laryngoscopic examination and EGG were performed at baseline, 6weeks, and 3months post-CCRT; Grades of LT and contact quotients(CQ) were documented. Patientreported outcomes of voice-related quality of life(QoL) performed at the same intervals, using a 30-item Voice Symptom Scale (VoiSS) questionnaire.

Statistical analysis: Results of continuous measurements were studied by mean +/- standard deviation. Analysis of variance (ANOVA) was used for comparison of pretreatment and post-treatment results in more than two groups. Significance was assessed at 5% level ofsignificance. Post- hoc analysis has been done using Tukey-Krammer method for multiple comparisons. Correlation analysis was performed using Pearson correlation test.

Results: 26/30 patients completed CCRT; 14 were available at 6weeks; 10 at 3months post-CCRT for analysis. At 6 weeks, 3/14(21.5%) patients had Grade II LT; 11/14(78.57%) had grade III. At 3months, 2/10(20%) had Grade I, 6/10(60%) had grade II but 2/10(20%) had worsened to grade IV. Mean CQ at baseline was 50.77 +/- 5.55; which decreased at 6 weeks to 48.56 +/- 4.66 and further at 3months to 45.56 +/- 4.66 (>0.05) suggestive of glottic hypo-adduction. VoiSS responses showed a significant impact on QoL in all three domains at six weeks and three months post-CCRT, compared to baseline (P < 0.0001).

Conclusion: Electroglottography is a potential tool to quantify acute LT post CCRT. Patient-reported outcomes may not correlate to the objective measures of laryngeal toxicity and require separate recording and reporting. A larger sample size would be required to draw further significant correlations. Key Words: Electroglottography; laryngeal toxicity; head neck cancer; voice; chemo-radiotherapy.