**1. Introduction**

Oral cancer is a malignant head and neck disease, and it accounts for 2–5% of cancer types and around 30% of head and neck cancers [1, 2]. According to the World Health Organization classification 2017, oral cancer is defined to tumors in the buccal mucosa, the anterior two-third of the tongue, the lip, palate, vestibule, alveolus, floor of the mouth, and gingivae [3]. Cancers of salivary glands or oropharynx will not be discussed in this chapter.

Oral cancer is distributed high in countries such as India, Pakistan, Taiwan China, and Germany [4]. It is more frequent in men than women [5]. It has a complicated etiology and it is related to many risk factors like tobacco, alcohol, betel nut, human papillomavirus (HPV) infection, et al. Around 90% of oral cancers are squamous cell carcinoma. In early stage of oral cancer, signs are unspecific and not easy to be recognized. As a result, most of the patients are diagnosed at a late stage, dropping down the survival rate from 80–90% to 20–50% [6]. Thus, the prognosis of oral cancer is poor and it is urgent to raise the awareness of public health education. The major management of oral cancer is surgery, supplemented with/without adjuvant radiochemotherapy. However, for better survival, personalized and multidisciplinary treatment strategies are needed.
