Application of Photodynamic Therapy for Treatment of Oral Cancer

Abstract

Squamous cell carcinoma of oral cavity (OSCC) is a malignant cancer induced by carcinogens and is a serious global health problem. Despite progress in oral cancer diagnosis and therapy, survival rate is very poor due to late detection, locoregional spread, and development of second primary tumors. Standard treatment methods such as surgery and radiation therapy can cause functional, cosmetic impairment and discomfort to the patients. Additionally, radiation and chemotherapy can cause adverse side effects due to poor selectivity, and the recurrence of tumor is high. Further, treatment of recurrent tumors with surgery or radiotherapy also poses problems. Photodynamic therapy (PDT) is a viable alternative to conventional less selective treatment approaches. PDT is based on administration of photosensitizer (PS) followed by selective illumination of target tissue with a visible light of wavelength that matches with absorption wavelength of PS used. The reactive oxygen species produced as a result of interaction between PS and light destroy tumor tissue selectively by either direct killing or damaging tumor vasculature and inducing antitumor immunity. In this chapter, we provide an overview of PDT and its application to oral cavity cancer treatment. Furthermore, a brief summary on the recent advances in PDT, particularly, delivery of PS to target tissue for enhancing the efficacy of PDT of oral cancer, is discussed.