[Abstract] Objective To evaluate the fidelity of dynamic laryngoscopy in diagnosing early vocal cord cancer, and the main indexes include sensitivity, specificity, missed diagnosis rate, misdiagnosis rate, and positive likelihood ratio. Also to evaluate the authenticity of fiberoptic laryngoscopy for the diagnosis of early vocal cord cancer. Methods A blinded controlled experiment was used to diagnose patients with dynamic laryngoscopy and fiberoptic laryngoscopy video without knowing the pathological results according to the unified diagnostic criteria by ENT clinicians experienced in laryngoscopy, and the diagnostic conclusion was contrasted with the pathological results of biopsy. The formula of the clinical epidemiological diagnostic test was applied to calculate. The results showed that the sensitivity (Sen) of dynamic laryngoscopy was 86.2%, the leakage rate was 13.8%, the specificity (Spe) was 86.8%, the misdiagnosis rate was 13.2%, the correct diagnosis index was 73.0%, and the positive likelihood ratio was 6.53. The sensitivity (Sen) of fiberoptic laryngoscopy was 76.7%, the leakage rate was 23.3%, the specificity (Spe) was 73.5%, and the misdiagnosis rate was 26.5%. Conclusion Dynamic laryngoscopy and fiberoptic laryngoscopy have high sensitivity and specificity in the diagnosis of early laryngeal carcinoma, which is beneficial to the early detection of laryngeal carcinoma. [Keywords] Early laryngeal tumor; laryngoscopy; diagnosis; dynamic laryngoscopy; fiberoptic laryngoscopy The use of dynamic laryngoscopy for laryngeal examination was first described by Oertel in 1895 [1], and in 1932 Kallen explained the optical characteristics of the stroboscopic source and the principle of dynamic laryngoscopy [2]. in 1961, Von Leden suggested that electronic dynamic laryngoscopy could be a promising diagnostic tool [3]. The first dynamic laryngoscope was introduced to the PLA General Hospital in 1975 and applied clinically, and in 2002, our hospital acquired the leading dynamic laryngoscope and computer graphic processing system in China, which improved the diagnosis and functional assessment of laryngeal diseases. At present, dynamic laryngoscopy is used in a considerable number of hospitals in China, and the value of assessment of functional laryngeal diseases is recognized because of the ability to visually observe the vibrating mucosal fluctuations of the vocal folds. In our clinical practice, we found that dynamic laryngoscopy also has its advantages for the diagnosis of early laryngeal cancer. To illustrate the application value of dynamic laryngoscopy in diagnosing early vocal fold cancer, this paper applies a blinded controlled diagnostic experiment to evaluate the authenticity of dynamic laryngoscopy in diagnosing early vocal fold cancer and compare it with fiberoptic laryngoscopy in diagnosing early vocal fold cancer. 1. Materials and methods 1.1. Clinical data: From March 2003 to April 2004, a total of 3842 patients underwent laryngoscopy in the ENT clinic of PLA General Hospital, 1224 patients underwent dynamic laryngoscopy and 2618 patients underwent fiberoptic laryngoscopy. Among them, 59 cases of pathologically confirmed early-stage vocal hilar cancer were examined by dynamic laryngoscopy in 29 cases and by fiberoptic laryngoscopy in 30 cases. Early-stage vocal fold cancer included (1) carcinoma in situ. (2) limited lesions on one side of the vocal folds with normal vocal fold activity; (3) lesions on one side of the vocal folds, not exceeding the anterior union and vocal fold prominence, with normal or slightly diminished vocal fold activity. The supraglottic and infraglottic laryngeal carcinomas were excluded [4]. 59 cases were all male, aged 47-85 years, with a mean age of 62.5 years. Pathological types included 57 cases of squamous epithelial carcinoma, 1 case of sarcomatoid carcinoma, and 1 case of embryonal rhabdomyosarcoma. We randomly selected cases with primary lesions in the vocal cords that had to be differentiated from carcinoma of the vocal cords and were pathologically confirmed to be nonmalignant among the laryngoscopically examined cases as a control group. There were 38 cases in the dynamic laryngoscopy control group, 29 males and 9 females. There were 12 cases of vocal cord polyps, 9 cases of chronic inflammation of vocal cord mucosa, 2 cases of mild atypical hyperplasia, 1 case of leukoplakia with mild atypical hyperplasia, 6 cases of papilloma, 2 cases of granuloma, 3 cases of epithelial keratinization, and 3 cases of epithelial hyperplasia diagnosed by pathology. There were 34 cases in the fiberoptic laryngoscopy control group, 23 males and 11 females. There were 10 cases of vocal cord polyps, 8 cases of chronic inflammation of vocal cord mucosa, 2 cases of mild atypical hyperplasia, 3 cases of leukoplakia, 6 cases of papilloma, 2 cases of granuloma, and 3 cases of epithelial hyperplasia diagnosed by pathology. 1.2. Equipment and methods: Dynamic laryngoscope with 90-degree straight tube magnification laryngoscope from WOLF, Germany, WOLF5052 strobe light source, WOLF5507 high-definition CCD video recorder, SONY monitor. The fiberoptic laryngoscope was manufactured by Olympas, with the same light source and video recording system. The images of the examination were captured and recorded with Tiger’s graphic processing software. The valuable videos were stored on disk for permanent retention. 2. Results: 2.1. Diagnosis of early carcinoma of the vocal tract by dynamic laryngoscopy. Diagnostic criteria: the lesion was confined to one side of the vocal folds, without supra- and subglottic invasion, with good or slightly restricted vocal fold motion, and one of the following manifestations was diagnosed as early vocal fold cancer: (1) localized or full-length swelling of the vocal folds, lobulated or cauliflower-like, with uneven surface, sometimes with grayish-white pseudomembrane covering the surface, diminished or disappeared mucosal wave under the frequency flash source, and diminished or disappeared amplitude. (2) Full-length or limited elevation of the vocal folds, with an unsmooth surface or white spots, surrounding congestion, loss of normal color and luster of the entire vocal folds, weakening or disappearance of mucosal waves under the strobe light source, and weakening or disappearance of amplitude.