Genetic considerations

Imaging after breast-conserving surgery – Routine surveillance

Patients who have undergone breast-conserving surgery should be referred for annual mammography of both breasts.

Patients who have undergone a unilateral mastectomy should be referred for annual mammography on the intact breast.

Patients may choose to return to BreastScreen for routine annual mammographic surveillance after 5 years.

Consider the addition of ultrasound to mammography for follow-up, when indicated on clinical or radiological grounds.

Adjuvant chemotherapy – Indications #2

The choice of neoadjuvant or adjuvant chemotherapy should be determined by a patient’s comorbidities, physical function, and degree of frailty, and not by gene mutation status or age alone.

Imaging after breast-conserving surgery – Young patients with high-risk gene mutation

In patients less than 50 years of age who are carriers of high-risk gene mutations (e.g. BRCA1/2) and who have not undergone risk-reducing mastectomy, consider the use of annual magnetic resonance imaging (MRI) of both breasts during follow-up.

BCS or mastectomy – Patients with gene mutation

In patients with breast cancer with a confirmed germline mutation (e.g. BRCA1/2), that predisposes to an increased risk of breast cancer discuss the options of breast-conserving surgery, mastectomy or bilateral mastectomy, noting that there is a higher risk of a second malignancy if the breast is conserved, but that this risk is reduced by adjuvant systemic therapy.

Gene expression profiling

If considering the use of tumour gene expression profiling tests to inform decisions about the use of adjuvant chemotherapy for patients with breast cancer, be aware that the clinical utility of these tests has not yet been established. Discuss with the patient the potential benefits (reduced adverse events due to avoiding chemotherapy) and potential harm (breast cancer recurrence that might have been prevented) of using these.

Genetic risk assessment

All patients with breast cancer should be assessed at or around the time of diagnosis for familial and genetic risk factors as indicated in current eviQ guidelines, which include relevant pathogenic variants in adult blood relatives, gender, ancestry, breast cancer characteristics, and personal and family cancer history.

Genetic counselling and testing – Referral

In accordance with eviQ guidelines, patients suspected of having high familial or genetic cancer risk should be referred to a family cancer clinic for genetic counselling and genetic testing as appropriate.

Radiation therapy – Patients with p53 mutations

Wherever possible avoid radiation therapy in patients with p53 genetic mutations.

Risk-reducing strategies #2

In premenopausal women with breast cancer with a confirmed germline mutation (e.g. BRCA 1/2) that predisposes to an increased risk of breast cancer, discuss risk-reducing strategies (e.g. contralateral risk-reducing mastectomy or endocrine therapy/ risk-reducing medication).

Risk-reducing strategies #3

In women with breast cancer with a confirmed germline mutation (e.g. BRCA 1/2) that predisposes to an increased risk of ovarian/fallopian tube cancer, refer to a gynaecological oncologist for discussion of the benefits and risks of bilateral salpingo-oophorectomy (BSO).