Head and neck cancer of unknown primary: unveiling primary tumor sites through machine learning on DNA methylation profiles

Table 4 Incidences of different tumor entities that metastasize to lymph nodes in the head and neck region

Tumor entity	Incidence (worldwide 2020)	SCC proportion	Incidence SCC	Proportion of cervical metastasis	Incidence of cervical metastasis	Proportion of all cervical metastases	References
Lung cancer	2,206,771	27.5%	606,862	1.5%	9,103	2%	[21]
ESCC	604,000	100%	604,000	18.1%	109,324	22%	[22, 23]
HNSCC—oral cavity	377,713	100%	377,713	60%	226,628	45%	[24]
HNSCC—larynx	184,615	100%	184,615	50%	92,308	18%	[25]
HNSCC—oropharynx	98,412	100%	98,412	60%	59,047	12%	[24]
Non-melanoma skin cancer	1,198,073	13.8%	1,198,073	4%	6,589	1%	[26]
Total					502,999	100%

Incidence numbers were taken from the Global Cancer Observatory [19]. The proportion of cervical metastasis was approximated based on relevant literature, as noted in the reference column

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