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Breast cancer is
cancer of breast tissue. Worldwide,
breast cancer is the most common
form of
cancer in
females, affecting approximately 10% of all women at some stage of
their life in the Western world. Although significant efforts are made
to achieve early detection and effective treatment for breast cancer,
about 20% of all women with it will die from breast cancer , and
breast cancer is the second most
common cause of
cancer deaths in
women.
Increasing Signs and Symptoms of Breast Cancer
The risk
of getting breast cancer increases with age. For a woman
who lives to the age of 90 the odds of getting breast cancer her
entire lifetime is about 12.5% or 1 in 8. Men
can also develop breast cancer, although their risk is
less than 1 in 1000. This risk is modified by many different factors.
In some families, there is a strong inherited familial risk of breast
cancer. Some racial groups have a higher risk of developing breast
cancer - notably, women of European
and African descent have been noted to have a higher rate of breast
cancer than women of Asian origin.
Other
established risk factors include having no children, delaying first
childbirth, not breastfeeding, early menarche (the first menstrual
period), late
menopause
and taking
hormone replacement
therapy.
The
probability of breast cancer rises with age but breast
cancer tends to be more aggressive when it occurs in younger women.
One type of breast cancer that is especially aggressive and disproportionately
occurs in younger women is Inflammatory
Breast Cancer. It is initially staged as Stage IIIb or Stage IV. It also is unique because it often does not present with a lump so
that it often is not detected by mammography or ultrasound. It presents
with the signs and symptoms of a breast infection like mastitis.
Two
genes, BRCA1 and BRCA2, have been linked to the familial form of breast
cancer. Women in families expressing mutations in these genes have
a much higher risk of developing breast cancer than women who do
not. Together with Li-Fraumeni syndrome (p53
mutations), these genetic abberations
determine around 5% of all breast cancer cases, suggesting that
the remainer is sporadic. Genetic counseling
and genetic testing should be considered for families who may carry a heritidary form of
cancer.
Identifying Breast Cancer Symptoms
Symptoms
of breast cancer are often subtle, and self discovery can
be alusive. Due to the high incidence of breast
cancer among older women, screening is now recommended in many
countries. Screening methods suggested include breast self-examination
and mammography. Only mammography has been proven to reduce mortality
from breast cancer. In some countries routine (annual) mammography of older women is encouraged as a
screening method to diagnose early breast cancer.
At this
stage mammography is still the modality of choice for screening of
early breast cancer symptoms. It is the gold-standard for other
imaging methods such as ultrasound, MRI and CT which are less useful
due to their lower spatial resolution. CT
by itself is nearly useless for breast cancer screening as
MRI provides better resolution and quality (and costs much more).
Breast
cancers detected by mammography are usually smaller than those detected
clinically, and women who undergo mammography are more likely to be
eligible for breast-conserving therapy.
Diagnosing Breast
Cancer
Breast cancers are diagnosed now
by mammography before they are large enough to be palpated, but despite
screening efforts, many women are diagnosed with breast cancer
after they notice a lump or when experiencing symptoms due to metastatic disease.
Breast
cancer can be suspected after a cautious clinical history, physical
examination and imaging (either mammography or ultrasound). The diagnosis of breast cancer can
only be established when a suspicious lump is biopsied
for histological confirmation of whether it is malignant or not. The
biopsy is usually performed either with a fine needle guided by
ultrasound or with a larger "core" needle. Some cases require
an open biopsy after wire localization under x-ray.
A
pathology report will usually contain a description of cell type and
grade. Other useful information derived from the pathology laboratoryincludes estrogen receptor and
progesterone receptors status and HER2Neu status; these can help to
guide treatment. The most common invasive breast cancer cell
type is infiltrating ductal carcinoma. Other
types include ductal carcinoma in situ
(DCIS), lobular carcinoma in situ (LCIS), infiltrating lobular
carcinoma, medullary carcinoma.
After
diagnosis, the next phase is tumour staging - this aims to assess the
extent of the tumour and whether or not it
has metastasized (spread to distant sites). Staging of Breast Cancer
For
suspicious, high risk cases, other investigations which include CT
scans, nuclear medicine imaging, chest X-rays and blood tests will be
done to look for any metastasis or secondary
cancer that has spread a long way
from the site of the primary tumour.
The
standard way of categorising tumour is by staging it using the TNM (Tumour, Nodes and Metastasis) system, which in turn
determines treatment recommendations. The TNM system is specific for
each type of
cancer. Some biological
features of the
cancer
such
as estrogen receptor and HER2-neu oncogene
expression are also determined as they also affect treatment
recommendations.
The TNM
classification of breast cancer:
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