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BACKGROUND:
Anatomy:
The basic
structure of the breast consists of milk-producing lobules
connected by lactiferous ducts, which in turn then collect
and drain at the nipple. These lobules are surrounded by
fat. Physiologically speaking, the breast is an extremely
active structure. During the premenopausal years, hormonal
variations during the menstrual cycle result in marked variations
in breast size and texture due to the effect of hormones on
the substance of the breast. During pregnancy and the immediate
postnatal period, the lobules swell and generate milk that
is constantly replenished during breast-feeding. During
the postmenopausal years, the lobules atrophy with decreasing
hormonal production, and breast size decreases.
The
most common site of breast cancer to arise is within the lactiferous
ducts. Typically, a breast cancer will arise within a duct
and then spread along its surface until it finally penetrates
through its lower layer to invade the surrounding breast structures.
Epidemiology:
Breast
cancer is predominantly a disease that occurs among postmenopausal
women, although with the widespread use of mammography, younger
women have become increasingly diagnosed with early stages
of the disease. Currently, roughly 70% of all cases are observed
among women older than 55 years.
Breast
cancer is one of the most common malignancies among women
worldwide, and is the most common malignancy among women in
the United States today. In the United States, it is estimated
that approximately 12% of all women will be diagnosed with
a form of breast cancer some time during their lifetimes.
Breast cancer is also a common cause of cancer-related death
worldwide and in this country. However, increasing use of
mammography has been demonstrated in several large studies
to substantially reduce the rate of cancer mortality by one-third.
With increasing use of mammography, it is hoped that breast
cancer-related death will decline substantially in the near
future.
Staging:
Medical
evaluation of the woman with breast cancer involves physical
examination, radiographic studies, and pathology confirmation
of disease.
Typically,
the woman presents to her primary care physician after having
noticed a lump in the breast. Less commonly, the woman is
noted on a routine mammogram to have a new mass present but
that is not palpable. In the event that a woman first notices
a breast mass herself, her primary care physician will then
schedule mammography in order to further evaluate the mass.
Mammography consists of a set of x-rays taken of both breasts
from various angles in order to assess optimally the size
and position of the suspicious lesion.
If
a suspicious lesion is indeed identified by mammography, then
the woman is next referred to a surgeon who may be able to
obtain a biopsy of the mass. If the mass is palpable, then
the surgeon may easily obtain a biopsy of it using a large-bore
needle in the office. If the mass is not palpable, then the
surgeon may need to arrange for a biopsy to be performed in
an operating room with the assistance of a radiologist.
In
this event, the woman is first taken to the radiology department
where a radiologist will identify the lesion under x-ray guidance
and place a thin wire through it. The woman is then taken
to the operating room where the surgeon uses the wire in order
to locate the tumor and remove it.
Once
a specimen of the tumor is removed, the specimen is sent to
the pathology department in order to obtain a reading. A
pathologist then makes the determination of whether the tumor
represents cancer or not.
Following
the diagnosis of cancer, several other tests need to be performed.
The tumor specimen will undergo several histologic tests,
most common of which is the assessment of estrogen and progesterone
receptor status. The assessment of receptor status is important
in that it may provide information regarding the prognosis
of the tumor, as well as dictate treatment management as will
be discussed below. Other tests include a bone scan and radiographic
evaluation of the chest and abdomen. These tests are commonly
performed for women with advanced stage breast cancer and
generally not for women with a small breast tumor.
Following
completion of all appropriate tests, a patient is then assigned
a stage for her disease. The staging system is intricate
but may be simplified as follows:
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Stage
1 - disease represents a small breast malignant
tumor without spread of the disease to the lymph nodes
under the arm.
Stage
2 - disease may be generally defined as either
a large breast tumor but without evidence of spread
of disease to lymph nodes or as a small breast tumor
with spread of disease to the lymph nodes.
Stage
3 - disease may be broadly defined as a very
large breast tumor invading into the skin or chest
wall, or any breast tumor with very large and malignant
lymph nodes under the arm.
Stage
4 - disease may be broadly defined as metastatic
disease, that is disease that has spread to sites
beyond the breast and nearby lymph nodes.
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Pathology:
Breast
tumors may be generally broken down into two types: non-invasive
and invasive tumors.
Non-invasive
tumors are malignant but have not yet progressed to the point
where they have broken through the basement membrane of the
structure from which they arise. These tumors are typically
not palpable and are most frequently identified by routine
mammography. These tumors offer the best prognosis for breast
cancer, as well over 90% of women diagnosed with non-invasive
disease are ultimately cured. The most common form of non-invasive
tumor is called ductal carcinoma in situ, in turn, may consist
of several subtypes including the following: comedo, cribriform,
solid, papillary, and micropapillary. Of these subtypes,
comedo ductal carcinoma in situ poses the greatest risk for
disease recurrence, although the risk for recurrence is still
fairly modest.
Invasive
forms of breast cancer include the following: infiltrating
ductal carcinoma, infiltrating lobular carcinoma, medullary
carcinoma, mucinous carcinoma, tubular carcinoma, among others.
Of these, infiltrating ductal carcinoma is by far the most
common, accounting for over 90% of all cases.
TREATMENT
OPTIONS:
Surgery:
Appropriate
management of breast cancer will include some form of surgery.
Traditionally, a mastectomy, which is the removal of the entire
breast and surrounding structures, has been the standard surgical
approach to breast cancer. However, over the past 20 years,
it has become increasingly clear that simply removing the
tumor itself while leaving the remaining breast intact and
then followed by radiation therapy to the remaining breast
offers disease control as good as mastectomy. The greatest
advantage of this surgical approach, called lumpectomy, is
that it offers definitive treatment of breast cancer while
allowing preservation of the breast itself. Following mastectomy,
a new breast can be reconstructed using skin and muscle from
the woman’s abdomen, but the cosmetic result is often not
nearly as good as that which follows a lumpectomy and radiation
treatment.
It
should be stated, however, that for women with large and advanced
breast tumors that mastectomy remains the treatment of choice.
Surgery
is usually necessary not only for management of the breast
tumor, but also for management of the nearby lymph nodes.
The lymph nodes most commonly associated with breast cancer
are located within the axilla which is a space underneath
the arm. These lymph nodes receive draining fluid from the
breast and therefore represent a site where disease may spread.
In the event that an invasive tumor has been diagnosed, a
surgical procedure of the axilla called an axillary dissection
is commonly performed. This axillary dissection commonly
removes approximately 10-15 lymph nodes from underneath the
arm of the effected breast. These lymph nodes are then evaluated
pathologically for evidence of spread of malignancy. The
reason for an axillary dissection is multifold: to provide
prognostic information regarding breast cancer, to help determine
the need for chemotherapy, to help determine the need for
radiation therapy to the local lymph nodes, and to help attain
better disease control within the local lymph nodes. In the
event of a non-invasive tumor, an axillary dissection is not
performed due to the very low risk of disease having spread
to these lymph nodes.
Radiation
Therapy:
The most
common use of radiation therapy for breast cancer today is
in the setting of postoperative treatment following a lumpectomy
as described above. The purpose of radiation treatment to
the entire breast following lumpectomy is to sterilize any
residual malignancy in the breast following surgery. Breast
cancer is generally a multifocal disease process. This means
that even though there is one tumor that is present within
the breast, that there is a high chance of further tumors
developing within that same breast over time. In fact, the
chance of a second breast tumor arising within a breast that
has been treated with lumpectomy alone approaches 50%. The
addition of radiation therapy following lumpectomy reduces
this risk to roughly 5%. Radiation therapy is therefore very
effective in sterilizing any residual tumor that may be present
in the breast following a lumpectomy. For early stage breast
cancer, lumpectomy followed by radiation therapy is quickly
becoming the standard of care if not already.
Chemotherapy:
Chemotherapy
for breast cancer is evolving constantly, but the common chemotherapeutic
drugs used today include Adriamycin, Cytoxan, and Taxol.
Typically, chemotherapy is given over a period of three to
six months during which time administration of the chemotherapeutic
drugs occurs every three to four weeks. The side effects
from chemotherapy may include but are not limited to the following:
loss of hair, poor appetite, decreased blood counts, and fatigue.
Chemotherapy is usually given following surgery, but may also
be given prior to any surgical treatment in the event of a
large, unresectable cancer.
There
exist some controversies regarding the use and benefit of
chemotherapy. Chemotherapy appears to offer the greatest
benefit to premenopausal women with node-positive breast cancer.
Other patient groups appear to benefit less from chemotherapy.
However, a medical oncologist is best qualified to determine
the need for chemotherapy in a given patient.
Although
not chemotherapy, Tamoxifen is a drug that has been used increasingly
for women with breast cancer. Tamoxifen is a drug which prevents
a woman’s estrogen from acting on estrogen sensitive tissue.
The use of Tamoxifen is particularly applicable to women with
estrogen receptor positive disease as previously discussed.
The idea is that Tamoxifen will prevent any residual cancer
cells that are hormone sensitive from being exposed to hormone
and then being stimulated to multiply. The administration
of Tamoxifen is by mouth and is given daily for a period of
five years. The side effects of Tamoxifen may include but
are not limited to the following: menopausal-type symptoms,
gastrointestinal upset, and weight gain or loss. Overall,
Tamoxifen is clearly recommended in women with estrogen receptor
positive disease. Also, Tamoxifen has been increasingly found
to be of benefit in women who are at high risk of developing,
but have not yet developed, breast cancer. These studies
are ongoing.
RADIATION
THERAPY:
Typical
Course:
The usual
situation is that the woman has undergone a lumpectomy and
may or may not have received chemotherapy following her surgery
before she is referred to the radiation therapy clinic. Following
surgery, usually a few weeks are required in order to permit
for adequate healing of the surgical scar. However, delay
before starting radiation treatment should not be excessive,
as delays of eight to 16 weeks after surgery have been found
to correlate with decreased disease control within the breast.
Following consultation with physical examination, the patient
is set up for what is called a treatment simulation. This
mainly consists of having the patient lie on a radiation treatment
table in the exact position that she is to be treated on a
daily basis thereafter. During treatment simulation, the
radiation therapist makes temporary marks on the skin surrounding
the breast to indicate the area that will be included within
the field of radiation. X-rays are then taken of the breast
from two separate angles. These angles are determined so
that radiation may pass through the breast while minimizing
exposure to the other breast as well as the underlying structures
of the lung, heart, esophagus, and spinal cord. A radiation
technologist obtains measurements of the breast and then calculations
are performed in order to determine the appropriate amount
of radiation to be given. Sometimes, a CT scan of the breast
is obtained in order to assist with these treatment planning
calculations. The entire process of treatment simulation
may be expected to take between 30 and 45 minutes. Following
treatment simulation, the patient is asked to return in approximately
two days in order to begin her actual treatment. The position
of the patient during treatment simulation is then repeated
with each actual radiation treatment. Each actual radiation
treatment session may be expected to take roughly five minutes.
Treatment is performed on a daily basis from Monday through
Friday with Saturdays and Sundays off. The total course of
treatment may be expected to take approximately six weeks.
During the course of treatment, the patient is evaluated by
her radiation therapist on a weekly basis in order to discuss
breast care during radiation treatment, as well as any other
issues of interest to the patient.
Following
completion of radiation treatment, the patient will need to
be evaluated on a regular basis by all of her treating physicians.
The typical course of follow-up will consist of evaluating
the patient six weeks after completion of radiation therapy
and then every six months for the first year. If an intact
breast was treated with radiotherapy, then mammography is
repeated every six months of that breast for the first year.
Side
Effects:
Side
effects from radiation treatment include but are not limited
to the following: redness and swelling of the breast, fatigue,
mildly decreased blood counts, and mild arm swelling. Unlike
chemotherapy, radiation therapy of the breast does not cause
loss of hair or nausea and vomiting. The skin changes during
radiation treatment are the predominant side effects of therapy.
Typically, the breast begins to turn pinkish approximately
two to three weeks after the start of treatment. For the
rest of treatment, the breast becomes increasingly red in
color and slightly sensitive, particularly around the nipple.
In some women, most commonly among patients’ with larger sized
breasts, the skin reaction might become quite uncomfortable.
Some peeling of the very top layer of the skin may occur,
revealing a raw area of the skin similar in appearance to
that of a “popped” blister. This reaction is most commonly
observed in areas where there is folding of the skin, such
as directly underneath the breast and armpit. Fortunately,
there are special lotions and medications that can be administered
to help relieve the sensitivity of the skin, as well as promote
its rapid healing. Following completion of radiation therapy,
the breast begins to heal and will require approximately two
to four weeks before the symptoms of radiation treatment have
resolved.
Although
not as prominent, there are also some long-term side effects
of radiation treatment. Over the course of months to years
of having completed radiation treatment to the breast, a woman
may notice that the skin of the breast has become slightly
darker in color, much like a light suntan. Alternatively,
there may actually be a decrease in the pigmentation of the
treated breast skin. Telangiectasias, which are very thin
and superficial blood vessels, may appear as a small collection
of very thin red lines on the skin of the breast with time.
Most commonly, however, is that the breast becomes slightly
firmer in texture and becomes a bit more uplifted than it
was prior to treatment. There may be some slight decrease
in breast size with treatment, but this rarely results in
the change of cup size following treatment.
Please
do not hesitate to discuss the radiotherapeutic management
of breast cancer or its side effects with any of our radiation
therapists at 21st Century Oncology. We are very happy to provide you with
the information that you need in order to make your decision
to receive radiation treatment an informed decision.
Constantine Mantz, MD
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