By accurately assessing a woman’s personal breast cancer risk level, health professionals can offer the most appropriate evidence-based prevention and early detection strategies. All women should therefore consider having their individual breast cancer risk assessed. This can be done by women themselves or in primary care. Cancer risk assessment should be repeated when major risk factors change (e.g. new family cancer history, breast biopsy showing atypical hyperplasia or LCIS).

There are a number of validated computerised breast cancer risk assessment tools that estimate a woman’s breast cancer risk based on her individual risk factors:

• iPrevent
• IBIS tool
• CanRisk Web Tool

iPrevent is an Australian tool designed for self-administration by women and collaborative use with clinicians and is the only tool that links the risk assessment directly to the relevant risk management guidelines.

In Australia, absolute lifetime population risk of breast cancer is 12 per cent, but most women are below this risk. Cancer Australia defines levels of breast cancer risk as follows:

• average risk: < 1.5 × population risk
• moderate risk: 1.5–3 × population risk
• high risk: > 3 × population risk (Cancer Australia 2010).

People with or without a personal history of breast cancer at high risk due to their family cancer history should be referred to a familial cancer service for further risk assessment and for possible genetic testing (eviQ 2019a). Consider referring:

• untested adult blood relatives of a person with a known pathogenic variant (mutation) in a breast and/or ovarian cancer predisposition gene (e.g. BRCA1 or BRCA2, TP53, PTEN, STK11, PALB2, CDH1, NF1) or
• people with two first- or second-degree relatives diagnosed with breast or ovarian cancer plus one or more of the following on the same side of the family:
• additional relative(s) with breast or ovarian cancer
• breast cancer diagnosed under age 50 years
• more than one primary breast cancer in the same woman
• breast and ovarian cancer in the same woman
• Jewish ancestry
• breast cancer in a male
• pancreatic cancer
• high-grade (≥ Gleason 7) prostate cancer.

Additionally, people with breast cancer should be referred to a familial cancer service if they meet the following criteria:

• male breast cancer at any age
• breast cancer and Jewish ancestry
• two primary breast cancers in the same person, where the first occurred under age 60 years
• two or more different but associated cancers in the same person at any age (e.g. breast and ovarian cancer)
• breast cancer aged under 40 years or triple-negative breast cancer aged under 50 years
• lobular breast cancer and a family history of lobular breast or diffuse-type gastric cancer
• breast cancer aged under 50 years with limited family structure or knowledge (e.g. adopted)
• breast cancer and a personal or family history suggestive of:
• Peutz-Jegher syndrome (oral pigmentation and/or gastrointestinal polyposis)
• PTEN hamartoma syndrome (macrocephaly, specific mucocutaneous lesions, endometrial or thyroid cancer)
• Li-Fraumeni syndrome (breast cancer < 50 years, adrenocorticocarcinoma, sarcoma, brain tumours).

Referral can also be considered if finding a relevant germline mutation would have high clinical utility (e.g. would alter treatment of the current cancer).