Tobacco, alcohol, pan:
Cigarette smoking and excessive alcohol consumption represent the most important factors for the development of HNSCC and they have a synergistic effect. Reverse smoking is a technique in which the lighted end of the cigarette is kept inside the mouth while smoking is a habit practiced in some areas of India and South America, leads to HNSCC of the hard palate. Chewing of the “betel quid’, which is popularly known as ‘pan’ is also considered an important risk factor for the development of HNSCC of the buccal mucosa and the mandibular buccal sulcus. The habit of betel quid chewing is highly practiced in countries such as India, Pakistan, Bangladesh and Sri Lanka. Although alcohol is not considered to be a carcinogenic agent, heavy alcohol intake along with tobacco use acts synergistically to cause HNSCC.