Familial cancer 

In familial cancer, not one but several members of the same family are at risk of developing the disease.

This reveals a vulnerability making the family more prone to develop one or several types of cancer. 

This vulnerability can be seen in the family history of cancer with a higher than normal number of cases. 

However, familial cancer is rare.  Most diagnosed cancers are Sporadic Cancer .

Familial cancer can be or not hereditary:

_{>  Non-hereditary familial cancer
>  Hereditary familial cancer}