Table 1. Criteria for cancer family history and genetic cancer risk classification.

Cancer family history	Criteria	Genetic cancer risk
Hereditary	At least one first and one second-degree relative affected by cancer	High
	Three or more family members with same or related cancers
	Exhibit classical cancers of hereditary cancer syndromes
	Majority of the cases exhibit an autosomal dominant pattern of inheritance
	Multiple primary cancers in an individual
	Presence of rare cancers
	Excess of bilateral cancers
	Presence of nonmalignant features previously associated with hereditary cancer syndromes
	At least one relative diagnosed at a younger than usual age
Familial	More cases of cancer within a family than statistically expected	Moderate
	More distant affected family members
	Does not often exhibit classical features of hereditary cancer syndromes
	Familial cancer clusters without a specific inheritance pattern
	Variable age of onset
Sporadic	Few or no first- or second-degree relatives affected by cancer	Low
	Cancer occurs in only one generation
	There is no particular pattern of inheritance
	Later age of cancer onset