Malignant Transformation of Dysplastic Vocal Fold Lesions

Abstract

The reported rates of malignant transformation of dysplastic laryngeal lesions are highly variable, as is time to malignant degeneration. To evaluate the rate of and time to malignant transformation of dysplastic laryngeal lesions based on the World Health Organization (WHO) dysplasia classification system. PubMed, MEDLINE, Embase, CINAHL, CENTRAL, and Cochrane Reviews were searched from the date of database inception to June 8, 2023. English-language articles assessing the rate of malignant transformation using the 2005 WHO dysplasia classification system were included in this systematic review and meta-analysis. The study was reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline. Data extraction was performed by 2 independent investigators. Study quality was assessed using a validated quality tool. When possible, data were pooled using random-effects meta-analysis. The primary outcome measure was the malignant transformation rate in each laryngeal dysplasia category. Secondary outcome measure was the time interval over which malignant transformation had occurred. A total of 5585 records were screened, 61 full texts were assessed, and 18 retrospective cohort studies with 3243 participants were included in the final review. The weighted pooled mean malignant transformation rates of mildly, moderately, and severely dysplastic lesions were 10.9%, 23.3%, and 30.5%, respectively. Malignant transformation rate of nondysplastic laryngeal lesions was 4.5%. Moderately and severely dysplastic lesions had significantly higher odds of malignant transformation compared with mildly dysplastic lesions (moderate: odds ratio [OR], 2.90 [95% CI, 2.06-4.09]; I2 = 0%; severe: OR, 3.42 [95% CI, 2.11-5.52]; I2 = 40%). Lesions without dysplasia had a significantly lower odds of malignant transformation compared with lesions with mild dysplasia (OR, 0.48; 95% CI, 0.28-0.81; I2 = 0%). The overall mean time to malignant transformation was 28.8 months (range, 22.0-35.6 months) for all dysplasia grades. This systematic review and meta-analysis found that the rate of malignant transformation increased with the grade of laryngeal dysplasia. Moderately dysplastic lesions were more likely to undergo malignant degeneration compared with mildly dysplastic lesions.