Role of perineural invasion as a prognostic factor in laryngeal cancer

The diffusion of laryngeal cancer cells in the perineural space is a parameter associated with a negative prognosis, high loco-regional recurrence and low disease-free survival rates. The spread of tumor cells on the perineural sheath highlights the histopathological and clinically aggressive behavior of this type of tumor, which may extend proximally or distally in the nerve for >10 cm. Therefore, the surgical resection margin is generally insufficient to treat patients with laryngeal cancer presenting with perineural invasion (PNI) with surgery alone. In PNI, the minor laryngeal nerves are frequently involved, rather than the superior and inferior laryngeal nerves. The aim of the present study was: i) To evaluate the prognostic importance of PNI; ii) to correlate the rate of infiltration with factors associated with the tumor, including histotype, site and tumor-node-metastasis stage, and with the type of surgery (total or partial laryngectomy); and iii) to evaluate the rate of disease-free survival according to the outcome of combined surgery and radiotherapy (RT) treatment, by means of retrospective analysis. The results of the present study highlighted the importance of performing a closer clinical and instrumental follow-up in patients with laryngeal cancer whose histopathological examination is positive for PNI. In such cases, it is important to complement the surgical therapeutic treatment with adjuvant RT.