Less than 10 percent of all breast cancers and less than 15 percent of ovarian cancers are associated with genetic mutations, or genetic errors if you like.
However, for those cancers that are caused by such genetic errors, BRCA-1 and BRCA-2 are the most common culprits.
There are no specific guidelines for diagnosing the presence of these genetic defects but they are suggested by:
– Clustering of breast and ovarian cancer in one family – particularly if there are three or more relatives.
– Development of cancer at an early age.
– Breast cancer or ovarian cancer on BOTH sides of the body (eg left and right breast or left and right ovary).
Image: iStock.
Q: WHAT ARE BRCA-1 and BRCA-2?
A: The normal BRCA-1 and BRCA-2 genes actually act to repair damaged DNA so as to prevent breast cancer.
Imagine that when they work normally these genes make little protective PAC-MEN that go around gobbling up and destroying any potentially cancer-causing changes in your DNA. The defective genes lose this ability.
The BRCA-1 and BRCA-2 gene mutations can therefore cause breast and ovarian cancer. Frighteningly, they are also more likely to result in a much earlier onset of these cancers.
They can also cause cancers of the fallopian tubes and pancreas. And men are not immune. A defective BRCA gene in males can result in an increased risk of prostate cancer and also cancer of the male breast.
Q: If you have the gene, what is the risk of cancer?
A: A woman with normal BRCA genes has an 11 percent risk of breast cancer, and about a 1.5 percent risk of ovarian cancer.
However, if they DO inherit the BRCA-1 gene, their cancer risks by the age of 70 are a staggering 65 percent for breast cancer and 40 percent for ovarian cancer. (Post continues after gallery.)
Sheryl Crowe.The American singer was diagnosed with breast cancer in 2006, and underwent a lumpectomy. (Image: Instagram)
Olivia Newton-JohnTragically, Newtown-John learned she had breast cancer on the same weekend her father died of liver cancer. Following her 1992 diagnosis, the Australian singer had a partial mastectomy and breast reconstruction. (Image: Twitter)Kylie Minogue.In 2005 Kylie was diagnosed with breast cancer at age 36. (Image: Instagram).Giuliana Rancic.While undergoing IVF in 2011, the E! anchor's doctor recommended she have a mammogram, which revealed she had breast cancer. Rancic had a double mastectomy. (Image: Instagram)Fran Drescher.The Nanny star was diagnosed with uterine cancer in 2000 - after two years of misdiagnoses by eight doctors - and underwent a hysterectomy. (Image: CBS)
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Delta Goodrem.he Australian singer was diagnosed with Hodgkin's lymphoma in 2003, when she was just 18. (Image: InstagramChristina Applegate.The actress had a double mastectomy in 2008 after being diagnosed with breast cancer at age 36.Cynthia Nixon.Nixon, who played Miranda Hobbes in Sex and the City, was diagnosed with breast cancer in 2006 at the age of 40. She has since become an activist for awareness of the illness. (Image: HBO).Angie EverhartIn 2013 the former supermodel announced she was battling thyroid cancer. Image via Instagram @angie_everhartSharon OsbourneOsbourne underwent surgery and chemo during her battle with colon cancer. Image via Instagram @sharonosbourneMelissa EtheridgeSuzanne SomersMarissa Jaret WinokurJoan LundenWanda SykesDame Maggie SmithJaclyn Smith
Q: What's the risk that the gene can be passed on to kids?
A: The child of someone that is BRCA positive has a 50 percent chance of inheriting the mutation.
Angelina Jolie’s mum, Marcheline Bertrand, died of ovarian cancer aged 56 after battling the disease for 10 years.
Her Mum’s Mum, Jolie’s grandmother, died aged only 45.
In fact, Jolie has been known to remark that there is ‘no longevity’ on her Mum’s side of the family.
So it seems apparent her mum - and likely her mum’s mum - were both BRCA-1 positive. Jolie of course confirmed she is BRCA-1 positive.
This means that little Shiloh, Vivienne and Knox also have a 50 percent chance of having this defective gene, and if so, having these extraordinarily high risks of breast and for the girls - ovarian cancer.
Q: What are the options?
A: If a woman has undergone testing and has been confirmed as BRCA-1 or BRCA-2 positive they have the following – incredibly difficult – options to choose from.
Watch and wait
- Some women may elect to not pursue surgery and to have ‘surveillance’ for any signs suggestive of cancer.
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- For breast cancer this would involve a yearly mammogram. For the ovaries this would entail six-monthly blood tests for ovarian ‘tumor markers’ and also pelvic ultrasounds with a vaginal probe to look at the ovaries.
- However, there is currently no great evidence that ovarian cancer screening like this significantly reduces a person’s risk of dying from such a cancer.
Surgery
Mastectomy
- Risk-reducing, or ‘prophylactic’ removal of both breasts – a bilateral mastectomy - decreases the incidence of breast cancer by as much as 90 percent or more in patients with BRCA mutations.
- There are different ways this surgery can be done. For example, Angelina Jolie had a ‘Nipple-Sparing Mastectomy’.
- This involves going in first, before the mastectomy, and sampling the tissue immediately behind the nipple and the lymph nodes.
- If this tissue is clear of cancer then the nipple can be kept at the subsequent mastectomy one to three weeks later to give a better cosmetic effect.
- However, one medical study suggests this procedure does not detect 12 percent of such cancers in this area. So, in other words, in 12 percent of cases the nipples are kept when they should not have been.
Removal of the ovaries and fallopian tubes:
- Removing both ovaries and fallopian tubes is actually recommended for BRCA-1 and BRCA-2 mutation carriers by the age of 35 to 40, or when the patient has completed their childbearing.
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- This decreases the risk of ovarian cancer from 40 percent down to between 1-2 percent, and – interestingly – also reduces the risk of breast cancer by 50 percent. We don’t really understand why.
So not uncommonly women will have recommended to them to undergo a bilateral salpingo-oophorectomy in conjunction with bilateral mastectomy.
Jolie has made no specific reference to her ovaries, or if she is contemplating having them removed. When you consider that it was actually ovarian cancer that claimed her Mother’s life, there appears to be an as yet untold story about what her whether she is considering having her ovaries and fallopian tubes removed.
Q: Can anyone get genetics testing in Australia?
A: If you’re worried about your risk you should firstly see your GP so they can do a full check up.
This may involve:
- Taking a full history and performing a complete physical examination.
- Blood testing for markers of tumours of the ovaries.
- Ultrasound scans of the pelvis looking for abnormalities of the ovaries.
- Mammograms or breast ultrasounds.
A patient can also seek out a genetic test specifically for the BRCA-1 and BRCA-2 mutation.
But, because this test is expensive – costing the Australian health system $2,000-$3000 - they can only be arranged through a Family Cancer Clinic.
At these clinics a highly skilled genetic counselor talks to the patient, assesses their risk, and if the risk of finding a mutation is estimated to be higher than 10 percent, they perform the testing.
If a mutation is found, the testing is then performed on other family members.
Brad is a specialist obstetrician and gynaecologist who works out of the practice Greenslopes Obstetrics & Gynaecology at the Greenslopes Private Hospital in Brisbane. After previous careers he was inspired to fulfill his lifelong dream of becoming a doctor following a trip to some of the most impoverished areas of Africa. Find out more at bradrobinson.com.au.
Do you have a family history of breast cancer? Would you get the test? And what would you do if it was positive?
