Table 1.

Numbers of family members of probands and their person‐years, number of families by number of cancer cases among family members and number of familial cancers and of families with familial cancers by primary site, including follow‐up and cancer cases of family members at 0–40 years of age

				Number of families
		Family members of probands		Number of cancer cases among family members							Familial cancers
Primary site	ICD‐10	Number	Person‐years	01	1	2	3	4	>4	Total1	Number of cancers	Number of families (proportion of families with familial cancers)
Brain and other CNS	C70–72, D32–33, D42–43	49,712	935,387	5,346	76	0	1	0	12	5,424	85	78 (1.4)
Colorectum	C18–20	20,536	383,189	1,922	33	5	1	0	0	1,961	46	39 (2.0)
Breast	C50	54,766	992,156	5,465	96	2	0	0	0	5,563	100	98 (1.8)
Melanoma	C43	29,894	536,409	3,070	26	0	0	0	0	3,096	26	26 (0.8)
Other primary	C00–17, C21–42, C44–49, C51–69, C73–96 D09.0‐1, D41, D45–47, D76	226,870	2,650,641	24,231	253	8	1	1	0	24,494	276	263 (1.1)
Total		376,7623		40,034	484	15	3	1	1	40,538

¹Excludes families where proband has no family members.

²Six cancers in one family.

³The number of unique relatives.