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FAMILIAL
BREAST CANCER
Breast Cancer occurs
commonly in the U.K. and so many women will have one or two relatives
with breast cancer by chance alone especially if the family is big and
not due to any hereditary factors. It is estimated that lifetime risk
of developing breast cancer in women is 1 in 12.
Hereditary cancer and familial breast cancer are 2 interchangeable terms
used to describe breast cancer in the family.
Hereditary
Breast cancer:
Hereditary breast cancer refers to cancer that occurs when the family
history suggests members with early onset breast cancer, high incidence
of breast cancers in both the breasts and association with other cancers.
They have usually identifiable mutations in the genes called BRCA1 and
BRCA2. They constitute about 5-10% of all breast cancers. The presence
of one of these genes does not automatically mean that breast cancer will
develop, but the risk is estimated to be 50-70% by age 50 years and 80%
by the age of 70.
Familial
Breast Cancer:
On the other hand familial breast cancer implies 2 or more first-degree
relatives have had breast cancer and some other familial factors are thought
to underlie the development of the disease. They may have mutations in
other genes, which are unknown at the present time. But with the several
affected members in the family, genetic testing may be indicated to determine
if there is indeed an underlying specific mutations described previously.
What
is the likelihood of inheriting a genetic susceptibility to breast cancer
if some body has a family history of breast cancer?
- 4 or more relatives
affected by breast or ovarian cancer at any age.
- 3 relatives on
the same side of the family with breast or ovarian cancer with average
age of diagnosis of breast cancer < 60.
- 2 relatives on
the same side of the family affected with breast or ovarian cancer with
average age of diagnosis of breast cancer < 40.
- 2 first or second-degree
relatives wit one or bot of them having bilateral breast cancer.
- Breast and ovarian
cancer in the same woman of any age
- 2 first or second-degree
relatives affected in the same side of the family with Jewish ancestry.
- One first or second
degree with breast cancer at age 45 plus another first or second degree
relative on the same side of the family with sarcoma at age 45 or younger.
- Member of the family
where the mutation has been established.
What
about genetic testing?
Since genetic
mutation resulting in breast cancer occurs only in 5-10% of all breast
cancers the patients are carefully selected after identifying the high-risk
patients as described in the earlier paragraph. They are subsequently
referred to the regional clinical genetic service. The patients are counselled
prior to the testing, as there are many implications to consider.
In the first instance
a sample of blood needs to be taken from an affected family member so
that the altered gene can be identified. Only then, is it possible to
search for the mutation in unaffected relatives. At present, this process
is very time consuming and can take some months.
Implications of genetic testing:
Presence of
BRCA1 and BRCA2 mutations in a person signifies the high risk of developing
breast and ovarian cancer. However it does not mean a 100% possibility
of developing these cancers. The risk is estimated to be 50-70% by age
50 years and 80% by the age of 70. So the testing offers the person to
have increased awareness and decide if she/he wants to have any treatment.
However on the other hand, even surgery cannot give 100% assurance against
developing cancer and the person needs to live in fear of cancer if she/he
does not want surgery. These things are to be considered before one venture
into genetic testing.
What
options are available for those at risk?
- Practising breast
awareness - being familiar with the look and feel of the breasts so
as to recognise any changes.
- Annual check ups
and regular mammograms (x-ray of the breasts) to screen for any abnormalities.
In younger women, the breast tissue is very dense and mammograms are
less helpful in this instance. Ultrasound of the breasts may be used
to help in the assessment of women under 35. The use of MRI scanning
(magnetic resonance imaging) for screening young women with a strong
family history of breast cancer is superior as well as complementary
to all other currently available tests. But it is not a cost-effective
tool for screening the masses.
- Surgery is an extreme
option and is known as prophylactic mastectomy where by both the breasts
is removed before the development of cancer. This greatly reduces the
risk but the possibility of developing cancer is still there though
it is small. This may develop because it is entirely impossible to remove
all breast tissue and the mutation is carried in all cells unlike in
sporadic breast cancer.
FAQ's
1.
What is 1st degree and 2nd degree relatives?
First degree - Parents and sisters, brothers and children.
Second degree - Aunts, uncles, nieces, nephews and grand parents on both
side of the family.
2.
Is it possible to have genetic mutation without any breast cancer in the
family?
Yes though it is uncommon. They develop because if there is a small family
there
may not be any cancer history or it may result from the de-nova mutation
of the
affected individual. But it can be suspected if some one develops cancer
at a very
early age, cancer in both breast etc.
3
What is an intermediate risk of developing cancer? (1.5-3 fold higher
than the normal population)
- 1 first degree
relative diagnosed with breast cancer <50
- 2 first-degree
relatives diagnosed with breast cancer <50 on the same side of the
family.
- 2 Second degree
relatives diagnosed with breast cancer on the same side of the family.
- Three first degree
or second degree relatives diagnosed with breast cancer with average
diagnosis of >60 years on any side of the family.
- 1 first degree
relative diagnosed with bilateral breast cancer.
- 1 first degree
relative diagnosed with male breast cancer.
4.
What is low risk of developing cancer? (The risk is <1.5 times the
normal population)
- No family History
of Breast cancer
- 1 first degree
relative diagnosed with breast cancer >50 years.
- 1 second degree
relative diagnosed with breast cancer at any age.
- 2 first degree
or second-degree relatives diagnosed with breast cancer at>50 years
on different sides of the family.
Research
organisations
Imperial
Cancer Research Fund, Cancer Research Campaign
PO Box 123, 10 Cambridge Terrace,
Lincoln's Inn Fields, London NW1 4JL
London WC2A 3PX Telephone: 020 7224 1333
Telephone: 020 7242 0200
Organisations
offering support and information
Breast Cancer
Care Hereditary Breast Cancer
Kiln House, Telephone Helpline: 01629 813000
210 Kings Road,
London SW6 4NZ
Telephone helpline: 0500 245 345
Website: www.breastcancercare.org.uk
If
you require further advice or information please contact the
Macmillan Breast Care Nurses, Hazel Ricard and Hilary Rickwood on 020
8565 5885
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