Thank you for the question! My answer is quite complex, please allow me to share below.
For the benefits of readers who might not be familiar with the term, "prophylactic mastectomy" refers to an operation to remove the whole breast
, to prevent breast cancer in a well woman.
Angelina Jolie brought this to international attention in 2013
, when she herself underwent such an operation. To summarise what is available in the public domain, her mother died from cancer at 56; and was diagnosed at 46. Ms Jolie herself underwent gene testing and discovered that she had a BRCA1 mutation, which highly increases her risk
of breast and ovarian cancer.
Family history alone should not be cause for alarm. In the local context, many nuclear families may not keep in touch with extended family, so we don't really know which of our blood relatives had cancers. This is important because, for genetic cancers, they tend to follow a pattern.
If you are aware of such cancers, do speak with your doctor. In my practice, I will do the initial counselling and screening to determine suitability for a genetics test, and refer to one of the few medical oncologists who further specialises in genetic testing and counselling.
The basics of genetics testing should ideally be: for the family members with cancer to have the genetics test first, to see what kind of mutations are present and THEN screen the interested well family members.
There're a few mutations which are well known and well studied so that doctors can advise a good preventive treatment plan. However, there may be dozens of other mutations for which we don't know if they cause an illness (or not!), or there's no treatment available.
Therefore, if you have family members with breast cancer- do speak with them to know more, and whether or not they had the genetics test. If yes, and they have the BRCA mutation, then it is good to consider a genetics test on yourself- if you have the BRCA mutation, your doctor will then speak with you for the necessary preventive surgeries: for breast cancer, and for ovarian cancer. All surgeries carry risks: of anaesthesia, bleeding, wound infections- so any decision should be made with good understanding of the pros/cons.