|
Most women share a common fear: developing breast cancer. This is
not an unfounded fear when considering that, except for lung cancer,
breast cancer is the most common cancer found in women, accounting for
one of every three diagnoses. However, men are also affected by breast
cancer. In 2002 the American Cancer Association estimate that 1500 men
will be diagnosed with breast cancer, and 400 will die as a result. In
2001 an estimated 192,200 American women were diagnosed with breast
cancer and 39,600 women died of the disease (The American Cancer
Association). In 2004 an estimated 203,500 new cases of breast cancer
will be diagnosed in America.
WHAT IS BREAST CANCER?
Breast cancer occurs when cells in the breast tissue divide and grow
without control. The cell cycle is the natural mechanism that regulates
the growth and death of cells. When the normal cell regulators
malfunction and cells do not die at the proper rate, there is a failure
of cell death (apoptosis) therefore cell growth goes unchecked. As a
result, cancer begins to develop as cells divide without control,
accumulating into a mass of extra tissue called a tumor. A tumor can be
either non-cancerous (benign) or cancerous (malignant). As a tumor
grows, it elicits new blood vessel growth from the surrounding normal
healthy tissues and diverts blood supply and nutrients away from this
tissue to feed itself. This process is termed “angiogenesis”- the
development (genesis) of new blood vessels (angio). Unregulated tumor
angiogenesis facilitates the growth of cancer throughout the body.
Cancer cells have the ability to leave the original tumor site,
travel to distant locations, and recolonize. This process is called
metastasis and it occurs in organs such as the liver, lungs, and bones.
Both the bloodstream and lymphatic system (the network connecting lymph
nodes throughout the body) serve as ideal vehicles for the traveling
cancer. Although, these traveling cancer cells do not always survive
beyond the tumor, if they do survive, the cancer cells will again begin
to divide abnormally and will create tumors in each new location. A
person with untreated or treatment-resistant cancer may eventually die
of the disease if vital organs such as the liver or lungs are invaded,
overtaken, and destroyed.
Cancerous tumors in the breast usually grow slowly. It is thought
that by the time a tumor is large enough to be felt as a lump, it may
have been growing for as long as 10 years. This has lead to the belief
that undetectable spread of tumor cells (micrometastasis) may have
already occurred by the time of the diagnosis. Therefore, preventive
measures such as a healthy balanced diet and lifestyle, nutritional
supplementation, and exercise are of primary importance against the
development of cancer. Early diagnosis is the best way to reduce the
risk of dying from breast cancer. This can be accomplished by monthly
self-breast exams, annual clinical breast exams and screening
mammography. If breast cancer is detected, a multimodality approach
incorporating nutritional supplementation, dietary modification,
detoxification, and one or more of the following may be considered:
surgery, chemotherapy, radiation, hormone therapy, or vaccine therapy.
RISK FACTORS
A wide variety of factors may influence an individual's likelihood
of developing breast cancer; these factors are referred to as risk
factors. The established risk factors for breast cancer include: female
gender, age, previous breast cancer, benign breast disease, hereditary
factors (family history of breast cancer), early age at menarche (first
menstrual period), late age at menopause, late age at first full-term
pregnancy, obesity, low physical activity, use of postmenopausal
hormone replacement therapy, use of oral contraceptives, exposure to
low-dose ionizing radiation in midlife and exposure to high-dose
ionizing radiation early in life.
Correlated risk factors for breast cancer include never having been
pregnant, having only one pregnancy rather than many, not breast
feeding after pregnancy, diethylstilbestrol (DES), certain dietary
practices (high intake of fat and low intakes of fiber, fruits, and
vegetables), tobacco, smoking, abortion, breast trauma, breast
augmentation, large breast size, synthetic estrogens, electromagnetic
fields, use of nonsteroidal anti-inflammatory drugs (NSAIDs), and
alcohol consumption. Alcohol is known to increase estrogen levels.
Alcohol use appears to be more strongly associated with risk of lobular
carcinomas and hormone receptor-positive tumors than it is with other
types of breast cancer (Li et al. 2003).
A novel growth inhibitor recently identified as estrogen
down-regulated gene 1 (EDG1) was found to be switched off
(down-regulated) by estrogens. Inhibiting EDG1 expression in breast
cells resulted in increased breast cell growth, whereas over-expression
of EDG1 protein in breast cells resulted in decreased cell growth and
decreased anchorage-independent growth, supporting the role of EDG1 in
breast cancer (Wittmann et al. 2003).
ANATOMY OF THE BREAST
The breast is composed mainly of fat (adipose tissue) and breast
tissue, along with connective tissue, nerves, veins, and arteries.
Breast tissue is a complex network known as the mammary gland. Within
the mammary gland, there are 15-20 lobes or compartments separated by
adipose tissue. Within each lobe are several smaller compartments
called lobules.
Lobules are composed of grapelike clusters of milk-secreting glands
termed alveoli, which are found embedded in connective tissue.
Spindle-shaped cells called myoepithelial cells, whose contractions
help propel milk toward the nipple, surround the alveoli. There are
about one million lobules contained within each breast (Spratt et al.
1995). The lobules are connected by tiny ducts that are joined together
(much like a grape stem) into increasingly larger ducts. Within each
breast there are between five and ten ductal systems, each with its own
opening at the nipple.
Surrounding the nipple is a darkly shaded circle of skin called the
areola. The areola appears rough because it contains modified sebaceous
(oil) glands. These glands secrete small amounts of fluid to lubricate
the nipple during breast-feeding.
Of all breast cancers, about 80% originate in the mammary
(lactiferous) ducts, while about 20% arise in the lobules (IOM 1997).
One of the most important distinctions to understand is the difference
between invasive breast cancer and carcinoma in situ.
TYPES OF BREAST CANCER
Invasive Cancer
When
abnormal cells from within the lobules or mammary ducts break out into
the surrounding tissue the condition is referred to as invasive breast
cancer. However, this term does not necessarily mean that metastases
have been found anywhere beyond the breast.
Carcinoma In Situ
Carcinoma
in situ is referred to as precancerous condition because it can
increase the risk of developing cancer. When abnormal cells grow within
the lobules or mammary ducts and there is no sign that the cells have
spread into the surrounding tissue or beyond, the condition is called
carcinoma in situ. The term in situ means “in place”. There are two
main categories of carcinoma in situ: ductal carcinoma in situ (DCIS)
and lobular carcinoma in situ (LCIS).
Non-invasive cancer is grouped into four subcategories, based on how
the cancer cells grow relative to each other within the center of the
milk duct:
Solid: There is wall-to-wall cell growth
Cribiform: There are holes between groups of cancer cells, making it look like Swiss cheese.
Papillary: The cells grow in fingerlike projections, toward the inside of the duct.
Comedo: There are areas of
"necrosis," which is debris from dead cancer cells; this indicates that
a tumor is growing so fast that some tumor cells die because there is
insufficient blood supply.
Carcinoma in situ is generally considered a slow-growing cancer. The
solid, cribiform, and papillary growth patterns are also referred to as
"low-grade" cancers. However, Comedo is considered a faster growing
cancer and is referred to as a "high-grade" non-invasive cancer, but is
more likely than other categories to become invasive.
Ductal Carcinoma In Situ
Mammary
ducts are hollow to allow fluid to pass through. However, with ductal
carcinoma in situ (DCIS) excess cells grow inside the mammary ducts.
DCIS is not invasive cancer. It is a precancerous condition that has
the potential to develop into breast cancer. DCIS is, however, a risk
factor for breast cancer.
Lobular Carcinoma In Situ
The
lobules of the breast tissue have open space inside them much like the
mammary ducts. Lobular carcinoma in situ (LCIS) is the growth and
accumulation of large numbers of abnormal cells within the lobules.
LCIS is often referred to as lobular neoplasia in situ. LCIS is not a
direct cancer precursor. The abnormal cells found inside the lobules
are not likely to mutate into cancer. LCIS is, however, a risk factor
for breast cancer.
SPECIAL MANIFESTATIONS OF CANCER
Paget's Disease of the Nipple
Paget's
disease is a rare, slowly growing cancer of the nipple. Paget's disease
is usually associated with in situ or invasive cancer. One of the
biggest problems with Paget's disease of the nipple is that its
symptoms appear to be harmless. It is frequently thought to be a skin
inflammation or infection, leading to unfortunate delays in disease
detection, diagnosis and treatment. Symptoms of Paget's disease include
persistent redness, itching, oozing, crusting, and fluid discharge from
the nipple or a sore on the nipple that does not heal. Typically, only
one nipple is affected. Treatment and prognosis for the disease are
directly related to the type and extent of the underlying cancer.
Inflammatory Breast Cancer (IBC)
Inflammatory
breast cancer (IBC) is a rare and aggressive form of invasive breast
cancer that is usually not detected by mammograms or ultrasounds. IBC
usually grows in nests or sheets rather than as a confined solid tumor
and can be diffuse throughout the breast with no palpable mass. The
cancer cells clog the lymphatic system just below the skin, resulting
in lymph node involvement. Increased breast density compared to prior
mammograms should be considered suspicious.
However, the main symptoms of IBC are breast swelling, inflammation,
pink, red, or a dark colored area (erythema), sometimes with texture
similar to the skin of an orange (peau d'orange), ridges and thickened
areas of the breast skin, an area of the breast that is warm to the
touch, what appears to be a persistent bruise, itching (pruritus) that
is unrelenting and unaffected by medicated creams and ointments,
increase in breast size over a short period of time, nipple flattening,
retraction, or discharge, breast pain that is not cyclic in nature and
may be constant or stabbing, or swollen lymph nodes in the armpit or
above the collar bone. Since many of these symptoms mimic a breast
infection, doctors frequently treat inflammatory breast cancer merely
as an infection. When symptoms do not improve after antibiotic
treatment for the suspected “infection” only then is the inflammatory
breast cancer diagnosed.
IBC has an extremely high risk of recurrence and a very poor
prognosis. It is the most lethal form of breast cancer. To improve the
chances of survival it is important that symptoms are recognized early,
resulting in an immediate diagnosis and treatment. Chemotherapy is
usually begun within days of diagnosis. Without treatment, chances of
5-year survival for individuals with inflammatory breast cancer are
very poor. With treatment, about 50% of patients will be living 5 years
after diagnosis.
BREAST DISEASES
There are a variety of breast diseases, ranging from infections to
excessive cell growth (neoplasms). Unfortunately, many breast diseases
mimic the symptoms of cancer and therefore require tests and possibly
surgical biopsy to obtain an accurate diagnosis. The majority of
biopsies are found to be benign (non-cancerous) forms of breast
disease. While most breast diseases are not dangerous in themselves,
they may increase the risk of developing breast cancer. Hyperplasia,
cysts, fibroadenomas, and calcifications are the common benign breast
diseases.
Calcifications
Calcifications
are randomly scattered residues of calcium that in older women may have
left the bones to appear in other parts of the body, such as the joints
or breasts. Microcalcifications are small, tight clusters of tiny
calcifications in the ducts that can be seen on a mammogram and may
indicate a precancerous or cancerous condition.
Cysts
Cysts
are sacs filled with fluid; they are almost always benign. Although
most are too small to feel, approximately a third of women between the
ages of 35-50 have cysts in their breasts. If large enough, cysts may
feel like lumps in the breast. Normally, cysts are left untreated.
However, if a cyst becomes painful, it can be aspirated or drained of
its fluid. Some women may prefer to have a cyst removed if, after being
aspirated repeatedly, it continues to recur.
Cysts are not associated with an increased risk of cancer; yet, they
are more common in women as they approach menopause and occur much less
frequently after menopause (Donegan 1995). What causes cysts to develop
is unknown; however, certain dietary factors, such as the intake of
caffeine have been proposed as possible risk factors for the
development of breast cysts.
Fibroadenomas
Fibroadenomas
are a type of benign lump most commonly found in younger women. They
are usually not removed since they pose no risk. If a fibroadenoma is
large, uncomfortable, and produces a lump, it may be removed. In older
women, fibroadenomas are generally removed to ensure that they are not
malignant tumors. Fibroadenomas do not pose an increased risk of cancer.
Hyperplasia
Hyperplasia
is not a precancerous condition. It is the excessive accumulation or
proliferation of normal cells typically found on the inside of the
lobules or the ducts in the breast tissue. Hyperplasia is associated
with approximately a two-fold risk of breast cancer.
Atypical Hyperplasia
Atypical
hyperplasia occurs when excess cells in the lobules or ducts are
abnormal. This condition falls between hyperplasia (too many normal
cells) and carcinoma in situ (too many abnormal cells). However,
atypical hyperplasia is associated with an approximately 3.5-5 times
increased risk of developing breast cancer (Page et al. 1985; Colditz
1993; Marshall et al. 1997).
| 
Print
PDF
Email
References
Suggested Products
