This content is part of a paid partnership with Breast Cancer Research Centre-WA.
Breast cancer is common, with a lifetime risk of one in eight for women. It is usually the result of chance and ageing with lifestyle and environmental factors also contributing. Five-year survival is greater than 90% due to early detection and advances in treatment.
In 5% of cases, there is an underlying genetic fault with either maternal or paternal inheritance. Red flag features in a particular family include multiple close relatives with breast or related cancers, cancer diagnosed at a young age (under 40) and more than one related cancer occurring in the same person.
Risk is estimated by assessing a woman’s first- and second-degree relatives with breast or ovarian cancer using the Cancer Australia publication Advice about familial aspects of breast and epithelial ovarian cancer. Alternatively, a validated risk assessment tool can be used.
Category 1 (average risk) comprises 95% of women. The lifetime risk of breast cancer is 1-1.5 times average (<17%).
Category 2 (moderately increased risk) comprises less than 4% of women. The lifetime risk of breast cancer is 1.5-3 times average (between 17% and 30%).
Category 3 (high risk) comprises less than 1% of women. The lifetime risk of breast cancer is greater than 3 times average (>30%).
iPrevent is a breast cancer risk assessment and management decision tool for clinicians and patients accessed at www.iprevent.net.au. It calculates a woman’s risk of breast cancer and facilitates prevention and screening discussions.
The CanRisk Web Tool found at www.canrisk.org is a comprehensive algorithm for use by clinicians to calculate patients’ risk of developing breast or ovarian cancer and their likelihood of carrying a genetic mutation.
Managing Women at increased risk
Lifestyle factors such as breastfeeding, healthy diet and weight, minimising alcohol and regular physical activity are often underestimated in importance. Hormonal contraceptives and menopause hormone therapy may increase risk and should be carefully considered on an individual basis.
Breast surveillance comprises breast self-awareness, clinical breast examination and surveillance imaging.
Mammography reduces breast cancer mortality and morbidity through early detection. The age of commencement and frequency of screening depends on a woman’s individual risk category. Women at average risk usually commence two-yearly screening at age 50. Mammography should start earlier and be performed more often (annually) for women in a higher risk category.
Additional surveillance such as breast MRI or ultrasound may be required for women at higher risk. Breast MRI should be considered as part of an overall high-risk management strategy in a designated breast clinic, as specific MBS criteria apply.
Prevention of breast cancer
Chemoprevention may be prescribed to women at moderate or high risk. Tamoxifen is on the PBS for this indication and results in a risk reduction of at least one third when taken daily for five years with benefit lasting at least 20 years. The potential risks need to be carefully balanced against the benefit for each individual by an experienced doctor.
Risk reducing bilateral mastectomy may be appropriate for some high-risk women, particularly those who carry a genetic fault. Referral to a Breast Surgeon for further discussion is important to allow women to make an informed decision.
Some genetic faults also confer an increased risk of ovarian cancer and gynaecological-oncology referral may be required to discuss risk management options. Ovarian surveillance with ultrasound or serum CA 125 is not recommended.
MBS-funded genetic testing may be accessed if there is a greater than 10% chance of identifying a gene fault using a validated risk calculation tool. Initial testing (mutation search) is ideally performed on an affected family member with predictive testing offered to blood relatives if a pathogenic mutation is found.
Referral to a genetic counsellor is important. Private testing is available for women who do not qualify for MBS funded testing, although the result may be uninformative.
High-risk breast clinics
These operate at both tertiary public and private breast clinics. A detailed assessment of a woman’s family and personal history is performed with implementation of personalised risk management strategies. Referral for genetic testing can also be made if indicated.
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