Inclusion Criteria

1)

Web-based search from Medline, Pubmed and Google Scholar

2)

Carefully review of titles and abstract of selected articles are available in English and limited to human research

3)

Articles reporting data on association between HNC, HNSCC and risk factors: (about smoking tobacco, alcohol, smokeless tobacco, betel nut and areca nut chewing, viral infection like HPV, dental hygiene, diet, family history, socioeconomic status, other heavy metals and systemic conditions, HNC, HNSCC) completing inclusion criteria

4)

Selected relevant studies for this review article

Exclusion Criteria

1)

Articles with clinical features, diagnosis, treatment, prognosis, and case reports were excluded.