Photodynamic therapy in the treatment of epithelial potentially malignant disorders of the mouth: advantages and disadvantages

Abstract

Introduction: Leukoplakia is a potentially malignant epithelial lesion with carcinomatous percentages transformation comprehended between 1% and 7% for the homogeneous forms and from 4% to 15% for the non-homogeneous ones. Their removal can be performed by scalpel or laser surgery (excision or vaporization). Photodynamic therapy (PDT) is a bloodless treatment option, based on the involvement of three elements: light, photosensitizer and oxygen. When the molecules of the photosensitizer are activated by a low power laser, energy is transferred to molecular oxygen creating highly reactive radicals of oxygen, that have a cytotoxic effect on target cells. Aim of the study: According to several studies in Literature, it has been decided to evaluate through an initial clinical trial, the efficacy of PDT using topical aminolevulinic acid (5-ALA) activated by a laser diode (λ = 635 nm) to treat potentially oral malignant lesions and to illustrate the advantages and disadvantages derived from the use of this technique. Materials and Methods: Five patients, affected by oral leukoplakia (OL) and oral verrucous leukoplakia (OVL) on the mucosal cheeks, labial commissure, fornix and retromolar areas, have been treated using the PDT. Irradiation time with Diode laser: 1000s. Irradiation mode: Scanning. 5 cycles of 3 minute + final cycle of 100 seconds. Each cycle has been interrupted by pauses of 3 minutes. Results and conclusion: PDT results to be effective in the treatment of OL, especially on OVL. In fact, OVL, due to its irregularity, has got an area of increased retention for the gel that is more difficult to be removed by salivary flow. This could explain the better results obtained in this case rather than in those ones of OL. Furthermore, the advantages have been represented by: less invasivity, high sensitivity for altered tissues, minimal scar tissue, less side effects and no pain during and after operation. In contrast to this, the disadvantages were: longer treatment duration and the high cost.