Healthy women who get breast cancer are often baffled by its unexplained origin, which adds to their stress and makes them wonder what they could have done to prevent it. The truth is that all breast cancers are caused by genetic abnormalities or mutations. What we don't know, but can establish through genetic screening, is whether these mutations are acquired or inherited.
Professor Maritha Kotze, researcher and lecturer in the Department of Pathology, Tygerberg Academic Hospital, says an acquired (non-hereditary) genetic abnormality, which accounts for about 80 percent of breast cancers, is caused by an error during gene reproduction or from interaction with environmental factors such as hormonal influences, toxic exposure or an inappropriate diet. Yet, despite this statistic, if you're diagnosed with breast cancer, the most common question is whether or not you have a family history of the disease.
In fact, abnormalities in breast cancer gene 1 or 2 (BRCA1 or BRCA2) account for less than five percent of the total breast cancer incidence and only about 20 percent of cases with a family history of breast cancer, says Professor Kotze. The figure increases to between 50 and 60 percent if more than one family member is affected.
Who should go for genetic screening?
If any of the following apply to you, you would benefit from genetic screening:
- If there's a family history of breast cancer which suggests an inherited pattern.
- If you have Ashkenazi Jewish or Afrikaner ancestry (referred to as 'founder' populations) with a family history of breast cancer.
- If you get bilateral breast cancer (that is, both breasts) at any age.
- If you are 35 or younger and have breast cancer or ovarian cancer before the age of 30.
- If you are a man with breast cancer.
- If a male member of your family has breast cancer.
If the mutation that caused breast cancer in an individual can be pinpointed, it's possible to screen for that mutation in other family members.
Huge advances have been made in the field of breast cancer over the last decade. For example:
- MammaPrint is a test that assesses the risk that a breast tumour will spread (metastasize) to other parts of the body.
- Intraoperative radiotherapy is the use of a single, high dose of radiation as additional therapy during surgical removal of a tumour.
- PARP inhibitors, drugs that can target the faulty gene, are being developed and offer hope of effective treatment and possibly of preventing breast cancer in people with BRCA mutations.
The genetic risk
- If you test positive for a BRCA1 or -2 mutation, you have a 50 to 90 percent chance of developing breast cancer. Professor Kotze says the range varies because even with a genetic predisposition, whether someone actually develops breast cancer depends on the effect of that mutation.
- If the test is negative for a specific mutation that caused cancer in your family, your risk for developing breast cancer goes down to that of the general population - which is approximately one in 10.
- With an inherited genetic abnormality, a child (male or female) has only a 50 percent chance of inheriting the faulty gene.
- If there's a history of breast cancer in the family, a genetic counsellor can calculate the risk of you testing positive for a specific mutation and suggest whether it's advisable to have a genetic test.
The psychological implications
Genetic counselling is essential before and after BRCA testing. And the implications of either a positive or negative result need to be considered in relation to treatment options and the impact the result can have on family members. Even though a BRCA positive result does not mean you'll definitely get breast cancer, it's easy to assume you will.
This can trigger anxiety, anger or depression. Genetic counselling can help prepare you and help you deal with this. A negative result after a full genetic screening also does not necessarily mean you will never develop breast cancer, as there may be other contributing genes which have not yet been identified, says Professor Kotze.
If you've been diagnosed with breast cancer, or if you're a family member of someone who has, there are advantages to knowing your BRCA status. Identifying the mutation can influence treatment and, for family members, knowing if they have the mutation or not influences health decisions and lifestyle choices.
Professor Justus Apffelstaedt, Associate Professor of Surgery at the University of Stellenbosch and Head of the Breast Clinic at Tygerberg Hospital, says a known family mutation puts women in control of the disease. But, because of the impact the information has on them, it often takes them a long time to accept it before deciding how to manage their risk.
Options if you have a BRCA mutation
In the past, many women opted to have mastectomies. As it's impossible to remove all the breast tissue, having a mastectomy reduces the risk of developing breast cancer to about 10 percent. Professor Apffelstaedt says the preferred choice is a total glandular excision in which the glands are removed but the skin, nipple and areola are left intact and the volume is filled with a prosthesis. This gives an almost natural-looking breast.
According to Professor Kotze, if a healthy person is tested and a BRCA mutation is detected, it can serve as an alert to make sure they get screened more often so that any signs of cancer development can be detected at an early stage, when the cancer is most treatable. Ultimately, it can be useful to know your genetic status, as long as you're mentally prepared for it.
Get your breasts examined at Clicks Clinics
Breast examinations are offered at all Clicks Clinics. Call 0860 254 257 to make an appointment at your closest clinic. A Clicks Clinic Sister will gladly examine any breast lumps you're concerned about and give you the advice and support that you need.