Table 1.

Epidemiological factors of multiple primary tumours

Epidemiological factors of multiple primaries
Host factors	Genetics	For example, ancestry, Li-Fraumeni and BRCA mutations
	Hormonal factors	For example, hormonal therapy and endometrial cancer
	Prior cancer diagnosis and treatment exposures	The incidence of a second malignancy is higher in a person with a previous cancer diagnosis compared with a person of the same age group without a prior cancer
Lifestyle factors	Alcohol	These are risk factors for several cancer types and are therefore more likely to develop more than one of these predisposed cancer types compared with people without these lifestyle factors
	Tobacco
Environmental influences	Geography	For example, cancer risk in areas of increased radon exposure
	Pathogens	For example, infections (human papillomavirus, Epstein-Barr virus)
	Occupation	For example, profession-associated cancer types like mesothelioma in workers with asbestos