Breast cancer: Genetic testing
Oncology leads the way in personalised medicine with a range of single and multi-gene tests to identify the patients that have increased risk of breast cancer development, recurrence or medication side-effects due to the genetic background. The DNA-based BRCA1 and BRCA2 gene testing and RNA-based profiling are offered as a routine service to patients who fulfil the criteria for these tests. More accurate testing is now available with the use of the multi-gene assays like the 70-gene MammaPrint profile.
Lifestyle diseases and breast cancer
Lifestyle disease like obesity, hypertension, insulin resistance, high cholesterol increase breast cancer risk.
Testing criteria
(Please use the questionnaire for testing criteria) (BRCA Tick List)
| BRCA1 & BRCA2 | MammaPrint |
| Personal risk : Bilateral / breast cancer and/or ovarian cancer diagnosed before the age of 35yrs; triple-negative breast cancer (ER-,PR-, HER2-negative) | Tumour size<5.0cm; Lymph nodes <3 |
| Familial risk : Male breast cancer and any family history of breast and other cancers, including prostate cancer; 4 affected close relatives younger than 60 years; 3 below 50 years; or 2 below 60 years and ovarian cancer | Stage 1-2; ER, PR positive / negative |
| Ethnic risks : Founder populations such as patients of Ashkenazi Jewish or Afrikaner ancestry with a family history of breast cancer | HER positive / negative ; Tamoxifen independent |
DNA-based BRCA1 & BRCA2 Test for Familial Breast Cancer
The screening is performed using a blood sample, saliva or a cheek swab.
Benefits of BRCA Mutation Detection
Genetic testing is most beneficial when it starts with a family member diagnosed with early-onset breast or ovarian cancer.
- A Positive result in a healthy individual justifies screening intervals to detect any signs of cancer development at an early stage when the cancer is most treatable. Risk-reduction surgery does not eliminate cancer, but only reduces risk.
- Testing can be beneficial in patients with breast cancer since the BRCA mutation will determine treatment.
About 50% of breast patients do not have a history of breast/ovarian cancer in their families and the onset of breast/ovarian cancer were drastically reduced with healthy lifestyle, physical activity and a healthy weight.
Genetic counselling
Genetic counselling is recommended post genetic testing and not recommended for children.
RNA-based 70-gene MammaPrint test for chemotherapy selection
MammaPrint is routinely performed on RNA extracted from a tumour biopsy and will tell the oncologist whether a patient with early stage breast cancer may benefit from chemotherapy or not. MammaPrint has the potential to reduce chemotherapy treatment with 60% when only a selected group needs chemotherapy. This will not only be beneficial to the patient, but can save medical aids R100 000 per breast cancer patient. Some medical aids will pay for MammaPrint (R24 000). I do believe in time to come most medical aids will pay for it.
Benefits of MammaPrint
- It is the only FDA approved test for breast cancer genetic profiling
- Cost effective
- It is the only test with a 5-year follow-up prospective clinical outcome
- Give results not possible with standard pathology
- Reduce chemotherapy in 60% patients with early onset breast cancer
- HER2/neu status routinely provide a separate readout used for Mamma print to confirm the analytical validity of using FFPE to replace the use of fresh tumour biopsies
Conclusion
Remember 70% of cancers are preventable. Live a healthy lifestyle, exercise, maintain a healthy weight, manage your stress and be happy. Never forget that life is short and so make sure you enjoy the journey.
