Many individuals have concerns about a family history of cancer. However, less than 10% of all cancer is due to an inherited predisposition. Even in those rare families where this is the case, unaffected family members have a greater than 50% chance that they will not develop an inherited cancer. It is unlikely that familial cancer clusters are inherited if:

• Different cancer sites are involved
• The cancers occur later in life
• The cancers have a strong environmental influence such as smoking or U.V. light

Breast Cancer

• 1 close relative, age under 40
• 1 close relative with bilateral disease
• 1 male relative, any age
• 2 close relatives, age under 60
• 3 close relatives, any age

Ovarian Cancer

• 2 close relatives with ovarian cancer, any age

Breast AND Ovarian Cancer

Minimum of 1 of each tumour; ovarian cancer any age, breast cancer age under 60  

Colorectal Cancer (or Colorectal Polyps)  

• 1 close relative age under 45
• 2 close relatives, average age under 70 (includes both parents)
• 3 or more close relatives, or with other gastrointestinal, renal, urinary tract, uterine or ovarian cancer at any age
• Familial Adenomatous Polyposis (FAP)

Other cancers  

• Multiple primary cancers in one individual
• 3 or more relatives with cancers at the same site
• 3 or more relatives with any cancer at an earlier age than expected in the general population
• 3 or more relatives with cancers of breast/ovary/prostate/pancreas/melanoma/thyroid, or other non-melanoma skin tumours or carcinoma

The overall benefit of surveillance outside these guidelines has not been established

Close relatives are:

• mother/father
• sister/brother
• son/daughter
• aunt/uncle
• grandmother/grandfather

Please make sure that you have considered recognised associated familial cancers when applying the guidelines.

If uncertain, please refer for assessment.