Head and neck squamous-cell carcinoma

Head and neck cancers are malignant neoplasms that arise in the head and neck region which comprises nasal cavity, paranasal sinuses, oral cavity, salivary glands, pharynx, and larynx. Majority of head and neck cancers histologically belong to squamous cell type and hence they are categorized as Head and Neck Squamous Cell Carcinoma (abbreviated as HNSCC). HNSCC are the 6th most common cancers worldwide and 3rd most common cancers in developing world. They account for about 5% of all malignancies worldwide (Ferlay J, 2010) and 3% of all malignancies in the United States (Siegel R, 2014). Head and neck cancers are malignant neoplasms that arise in the head and neck region which comprises nasal cavity, paranasal sinuses, oral cavity, salivary glands, pharynx, and larynx. Majority of head and neck cancers histologically belong to squamous cell type and hence they are categorized as Head and Neck Squamous Cell Carcinoma (abbreviated as HNSCC). HNSCC are the 6th most common cancers worldwide and 3rd most common cancers in developing world. They account for about 5% of all malignancies worldwide (Ferlay J, 2010) and 3% of all malignancies in the United States (Siegel R, 2014). Risk factors include tobacco consumption (chewing or smoking), alcohol consumption, Epstein-Barr virus (EBV) infection, human papilloma virus (HPV; esp. HPV 16 and 18) infection, betel nut chewing, wood dust exposures, consumption of certain salted fish and others (NCI Factsheet, 2013). EBV infection has been specifically associated with nasopharyngeal cancer. Reverse smoking was considered as a risk factor for oral cancer. Cis-retinoic acid (i.e. supplements of retinoic acid) intake may increase the risk of HNSCC in smokers. Low consumption of fruits and vegetables was associated with higher incidence of HNSCC.