TNM glottic: role of the vocal muscle, arytenoid cartilage, and inferior paraglottic space in impaired vocal cord mobility (T2). An embryological and clinical study

Analysis of recurrences in 322 Tis, T1, or T2 glottic carcinomas treated by carbon dioxide laser

An endoscopic approach to early glottic carcinoma is considered a sound treatment for both previously untreated lesions and selected recurrent lesions. Between January 1988 and December 2000, we treated 322 patients by CO2 laser at a single institution; 37 had Tis, 191 T1a, 55 T1b, and 39 T2 lesions (mean follow-up, 77 months; range, 6 to 180 months). Kaplan-Meier curves showed a 5-year overall survival rate of 88%, a determinate survival rate of 99%, a disease-free survival rate of 81%, a rate of ultimate local control with laser alone of 91%, and a laryngeal preservation rate of 97%. Univariate and multivariate analysis showed that the only factor that statistically affected endoscopic control was lateral extension of the tumor with involvement of the bottom of the ventricle (hazard risk ratio, 4.0; 95% confidence interval, 1.71 to 9.35). The 58 recurrences were classified according to their location compared with the site of the primary tumor as follows: 14 in the same area (group A), 27 in adjacent subsites with superficial spreading or multifocal distribution (group B), and 17 in adjacent sites by submucosal diffusion to the visceral spaces, cartilaginous framework, or extralaryngeal tissues (group C). For each group, we analyzed the rate of patients who underwent salvage by endoscopic or open neck procedures and the rate of laryngeal preservation. Recurrences in groups A and B were endoscopically treated in 86% and 74% of cases, respectively. By contrast, in group C no patient was endoscopically cured, and there was a low laryngeal preservation rate (47%). The pathways of spread in recurrent carcinoma are therefore the single most important factor in predicting its endoscopic curability.

Embryological study of the glottic site and clinical implications

The development of the glottic site, in particular of its ventral area, was studied to better understand the spreading pathways of T1, T2 cancer. Serial sections of larynges from human embryos, fetuses and adults were observed. A dorsal, a ventral and an intermediate compartment were found on the basis of their maturation schedule. A commissure muscle which develops in the anterior one third of the glottic site and wraps the connection system of vocal ligaments was recognized. The inferior paraglottic space, the compartment structures and the localization of superficial and deep blood vessels and of glands in the ventral compartment and the components of Broyles ligament were studied during ontogenesis. The compartments identified here have clinical and oncological relevance. Their detailed knowledge offers a prerequisite for planning and performing compartment conservative surgery in T1, T2 cancer, based on their spreading pathways.

Risk factors and prognosis of anterior commissure versus posterior commissure T1-T2 glottic cancer

For better understanding of the causation and behavior of T1-T2 commissural glottic laryngeal tumors, we retrospectively analyzed risk factors and outcome related to T class and type of therapy for tumors involving the anterior (184 cases) or the posterior (60 cases) commissure. The patients' smoking habits and alcohol consumption were similar, regardless of involved subsite. The disease-free interval was longer after surgery than after radiotherapy. The survival rates after recovery upon relapse were similar among subsites, T classes, and types of therapy. In anterior commissure tumors, the larynx remained preserved more frequently after partial laryngeal resection than after radiotherapy, and was more frequently preserved the lower the T class. In posterior commissure tumors, larynx preservation was less frequent and apparently independent of type of therapy or T class. In conclusion, smoking and alcohol consumption play similar pathogenetic roles in either subsite; partial laryngeal resection gave a higher rate of laryngeal preservation than did radiotherapy; and anatomic peculiarities of the subsites influence tumor behavior.