According to Dr Jones, most cancer is spontaneous and linked with lifestyle factors – meaning that it’s not necessarily a familial condition. However, there are certain types of cancer where a genetic link indicates an increased risk. “The big ones are breast, ovarian, prostate, bowel, melanoma and other skin cancer,” she says.
If you do have a family history of these cancers, you should start testing for them earlier than the general population. “For example, with bowel cancer, if you fit the criteria for a familial pattern then you would start getting screenings from 10 years younger than the age that the youngest family member was diagnosed at.”
When it comes to relatives, it’s those in your immediate circle that you should pay the most attention to. “First-degree family members – parents and siblings – share the most genes with you, so they’re the most relevant. Secondary relatives – like aunts, uncles, and grandparents – are next.”
Further out from that genetic inner circle, concern would only be raised if there’s a strong pattern of a specific cancer syndrome. “Sporadic cancers in cousins don’t make a huge difference unless they’re part of a bigger picture of many family members with the same type of cancer,” Dr Jones says. For more information, the Cancer Council of Australia has a comprehensive guide to family cancer history.