Table 3.

Patient demographics, clinical characteristics and risk factors.

First Author Year, Country	Patient Demographics	Clinical Characteristics	Risk Factors
Strüder et al., 2021, Rostock, Germany [26]	Patients with histopathologically proven HNSCC of the oral cavity, oropharynx, hypopharynx, larynx and neck lymph node metastases	Size of the tumor >2 cm; primary disease or recurrence; >18 years of age	Smoking 73% Alcohol 58% P16 15% positive
Kang et al., 2020 Kyungbuk South Korea [29]	Oral cavity cancer	Stage IV 68%	P16 positive 84.2%
Berggren et al., 2019 Albuquerque, NM [31]	Oral cavity, oropharynx, and larynx cancers	-	-
Lilja-Fischer et al., 2019 Aarhus Denmark [32]	Patients who underwent examination under anesthesia with diagnostic biopsies or tonsillectomy on suspicion of OPSCC	-	P16 positive 70.6%
Folaron et al., 2019 NY USA [33]	HHSCC cancers Clinical stage IVA	-	P16 positive 29.5%