What is invasive cancer?
If you have invasive ductal cancer, it means that cancer cells have
broken out of the ducts and moved into the surrounding fat tissue in
the breast. This is the most common type of invasive breast cancer.
About 1 in 10 (10 percent) of invasive breast cancers are invasive
lobular cancers. If you have this type of breast cancer, it means that
the cancer cells have broken out of the lobules and moved into the
surrounding fat tissue in the breast.
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How is it treated?
Most invasive breast cancers have been present for 8–10 years by the
time they have been detected on a mammogram or physical exam. During
that time there is plenty of opportunity for the cancer cells to get
out of the breast and spread to the rest of the body. Sometimes the
immune system takes care of these cells and sometimes it doesn't.
Because cancer can spread very early, two types of treatments are used
to treat invasive cancer. Local treatments—surgery and radiation—deal
with the disease in the breast and are aimed at preventing your cancer
from coming back in the breast. Systemic treatments—hormones and
chemotherapy—target any cancer cells that may have already spread into
the rest of your body. The usual order of treatment is surgery,
chemotherapy, radiation therapy, and, if the tumor is
hormone-sensitive, hormone therapy. If the tumor is HER2-positive,
Herceptin may be used along with or after chemotherapy (HER2 is also
sometimes referred to as HER-2 or Her-2/neu or erb-b2).
Surgery and Radiation
The main goal of local therapy is to prevent breast cancer from coming
back in the specific area in which the cancer appears. This can be done
by taking out as much of the cancer as possible in a lumpectomy and
letting radiation destroy any remaining cells. A second option is to
have a mastectomy. If the tumor is small, and you choose to have a
mastectomy, you will not need radiation. If it is large, you will need
to have a mastectomy, to remove as much of the tumor as possible, and
radiation therapy, to take care of leftover cells. It is important to
realize that you can have a local recurrence regardless of which
treatment you have. You can learn more about mastectomy and
reconstructive surgery in our feature story, "Breast Reconstruction—What You Need to Know."
Many women continue to believe that they will be more likely to survive
breast cancer if they remove one breast—or even both. For this reason,
more women than necessary continue to have mastectomies. If the idea of
removing the whole breast makes you feel better psychologically, that's
fine. But you should know that large randomized studies with as much as
20 years of follow-up have shown that both approaches—mastectomy and
lumpectomy followed by radiation—result in the same survival rates.
There are some situations where there may be reasons to choose a
mastectomy. If the area that needs to be removed is very large compared
to the breast itself, there will not be enough breast tissue left after
a lumpectomy to make it cosmetically worthwhile to have breast
conservation surgery. Also, women who carry a BRCA1 or BRCA2 genetic
mutation and have a high risk of other cancers developing in the
remaining breast tissue may find that bilateral mastectomy is the best
option for them.
Many women have the misconception that a
mastectomy will guarantee that the cancer will never come back again.
But a surgeon can never be certain that all the breast tissue has been
removed. This means cancer can come back again in the scar or the chest
wall.
Can you skip radiation if you have breast conservation
surgery? Studies have found that radiation does make a cancer less
likely to recur. But radiation does not appear to increase survival.
Does this mean more women than necessary get radiation? Yes. But do we
have any way of predicting who will get a recurrence (which will
require additional treatment) and who won't? No. For this reason, local
radiation is still the best option for invasive cancers treated with
lumpectomy.
Usually women who have a mastectomy don't
require radiation. Radiation is only recommended after a mastectomy
when there is a higher risk of recurrence because a woman has four or
more positive axillary lymph nodes; a tumor over 5cm; close margins
(cancer cells at the edge of the mastectomy); and significant amounts
of invasion of the lymphatic or blood vessels in the breast tissue.
Axillary Surgery and Sentinel Node Biopsy
Along with getting rid of the tumor, the surgeon will usually try to
discover if there are affected lymph nodes under the arm (axilla).
There are about 30–60 lymph nodes and a traditional lymph node
dissection involves removal of about 10–15 of these nodes. After they
are removed, the nodes are examined under a microscope. If they reveal
cancer cells, we assume there's a high probability of cancer cells in
other parts of the body. If the lymph nodes don't show cancer, it means
that there is a lower probability that there are microscopic cells
elsewhere in the body. This information will help the oncologist to
decide whether and how much adjuvant systemic therapy to give.
A 2-inch incision is made across the armpit. The surgeon will obtain
some fat from the hollow of the armpit that typically contains many of
the lymph nodes. After the nodes are removed, the incision is closed
with dissolvable stitches.
In recent years, there has been a
new variation on lymph node dissection that offers us a better way to
find out whether cancer has spread. This is known as sentinel node biopsy.
Sentinel node biopsy is a procedure designed to find the one node that
the surgeon believes is most likely to have cancer cells. The concept
is based on the theory that there are one or more nodes to which a
breast cancer is most likely to spread. Because a positive sentinel
node often predicts that there will be other positive nodes in the
axilla, the current standard of care is for women who have a positive
(cancerous) sentinel node to go on to have a full dissection. A
sentinel node biopsy is appropriate if: the tumor is in only one
location, the tumor is less than 5cm in size, you have not had previous
chemotherapy or radiation therapy, there is no large resection in the
upper outer quadrant (more than 6cm), and there are no palpable lymph
nodes.
It is important that you have an experienced sentinel
node team, beginning with the surgeon, perform the procedure. You
should ask your surgeon how many times she or he has done the procedure
and what percentage of the time she or he has been able to find the
sentinel node. It should be at least 85 percent (in most cases, in
fact, it's 90 or 95 percent). Also ask about the surgeon's false
negative rate. A false negative means the sentinel node was negative,
but there was a positive node someplace else. The false negative rate
should be under 5 percent. If a surgeon is unable, or unwilling, to
give you numbers, that's a pretty good sign that you should look for
another surgeon. If it turns out to be the surgeon's third or fourth
operation, find out who the supervising surgeon is. That's the person
who you want to have do your surgery.
You can read more about how to interpret the results of your sentinel node biopsy here.
Chemotherapy
After you decide about local treatment, you will need to decide about
systemic adjuvant therapy. Adjuvant means the treatment is given after
surgery. Treatment given before surgery is called neoadjuvant. To date,
studies have not found that giving chemotherapy before surgery makes a
difference in survival. But neoadjuvant treatment can provide
information about whether a tumor will respond to a certain type of
chemotherapy. Also, if a woman has a large tumor, neoadjuvant
chemotherapy can shrink the tumor, allowing the surgeon to perform a
lumpectomy instead of a mastectomy.
The drugs used for
chemotherapy act at different points in the cell cycle. Thus, using a
combination increases the likelihood that as many cells as possible
will be killed. In addition, multiple treatment cycles will ensure that
some cells left over from previous cycles will be killed in subsequent
cycles. The rationale is that any cells left over after this process
can be dealt with effectively by the immune system. You can learn more about the different drugs used for chemotherapy to treat breast cancer here
The treatments are given either on a 21-day or a 28-day cycle. On the
21-day cycle you are given a dose of therapy on every 21st day. On the
28-day cycle you are given a dose on the 1st and 8th day, and then
nothing for two weeks. Chemotherapy is generally given intravenously,
also called IV. In order to prevent the sometimes uncomfortable process
of placing an IV in the arm or leg, your doctor may suggest that you
have a permanent (although it is removed after therapy is over) IV line
put into a central vein in your chest.
Chemotherapy reduces
the risk of recurrence by about a third. This means that the higher the
chance of recurrence, the more beneficial the chemotherapy is likely to
be for you. If you have a 60 percent chance of recurrence, a one-third
risk reduction means chemotherapy will reduce your risk by 20 percent.
But if you have a 9 percent chance of recurrence, the one-third
reduction is only 3 percent. This is an important concept to understand
when trying to weigh risks and benefits. Adjuvant! can help you and your physician calculate the benefit you will receive from chemotherapy. You can also use our Cancer Profiler to understand your treatment options.
The side effects, which are dramatic and can sometimes limit the dose
of the drug you will receive, are the main reason that chemotherapy is
so terrifying to many women. We now have better drugs to prevent the
nausea that often accompanies chemotherapy, which has made chemotherapy
hard to take. After the first cycle you will know whether you will feel
sick and, if so, on which day the nausea hits and how sick you will
feel. Many women are able to continue their normal lives with minor
adjustments while receiving treatments. You won't feel great, but
you'll be functional.
You may feel exhausted much of the
time. Fatigue is due to anemia, which can be treated with a drug that
stimulates the production of red blood cells. You'll probably lose your
hair, beginning about three weeks after the beginning of treatment. You
may lose your appetite and food may taste different to you. Even so,
about 21 percent of women gain weight, usually between 5 and 15 pounds,
while taking chemotherapy. If you're premenopausal, you may have hot
flashes. If you're close to 40, the drugs may push you into menopause.
You may have vaginal dryness, which can cause pain during intercourse.
Infections in women who use IUDs and diaphragms are also more common.
Other common side effects include diarrhea or constipation. You may
also have bleeding gums, have nosebleeds, or pass blood in your urine
or bowel movements. Runny eyes and nose are also common. Patients
undergoing chemotherapy can become more susceptible to infections and,
as a result, develop mouth sores, conjunctivitis, or other problems.
Drugs like filgastrim (brand name Neupogen), which stimulates the
production of white blood cells, can help to reduce infections.
Making the decision about whether to have chemotherapy is not always
easy. It can be especially difficult for those women who have negative
lymph nodes. We know that between 30 and 40 percent of women with
negative lymph nodes will still get metastatic breast cancer—but we
currently don't have a way to identify who these women are. If you are
hormone-positive and have negative nodes, you may want to consider the Oncotype DX test. Recent research indicates that the test can help assess a woman's risk for recurrence. You may also want to look at the National Comprehensive Cancer Network's breast cancer treatment guidelines.
Hormonal Therapy
Hormonal treatments are used as adjuvant therapy for women whose tumors
are hormone-sensitive (ER-positive and/or PR-positive). Hormonal
therapies slow or stop cancer's growth by changing the hormonal milieu.
In women whose tumors are not sensitive to estrogen or progesterone,
hormonal therapies are useless and potentially harmful.
The benefit you will get from hormone therapy depends on your risk for recurrence. Adjuvant! can help you and your physician calculate the benefit you will receive from hormone therapy. You can also use our Cancer Profiler to understand your treatment options and possible side effects.
In December 2004, the American Society of Clinical Oncology (ASCO) issued new guidelines on hormone therapy.
ASCO now recommends that most postmenopausal women be treated with an
aromatase inhibitor. Previously, tamoxifen was the gold standard.
Tamoxifen remains the standard of care for premenopausal women.
Tamoxifen and aromatase inhibitors work in different ways. Tamoxifen
blocks the estrogen receptor in the breast and in breast cancer cells,
preventing estrogen from spurring cancer growth. It can be used by both
pre- and postmenopausal women. Aromatase inhibitors block an enzyme
called aromatase and keep it from converting androgens into estrogen.
Only postmenopausal women can use an aromatase inhibitor. That's
because postmenopausal women get most of their estrogen from the
conversion of androgens into estrogen by the aromatase enzyme, while
premenopausal women get most of their estrogen directly from their
ovaries.
You can read more here about how to decide whether an aromatase inhibitor or tamoxifen is right for you.
Herceptin (Trastuzumab)
Trastuzumab (brand name Herceptin) is a drug that is called a targeted
therapy. It is used to treat women whose tumors are HER2-positive.
(About 30 percent of the women with breast cancer have tumors that are
HER2-positive.) Herceptin was approved for use, in 1998, in women with
metastatic disease. In August 2005 researchers released interim results
from three separate Herceptin adjuvant trials that found that the drug
appears to decrease the risk of a cancer recurrence in women with
HER2-positive early breast cancer. The problem is the side effects:
Herceptin can increase the risk of heart problems. This means if you
want to consider Herceptin as adjuvant therapy, you must be closely
monitored by your physician. Read more about using Herceptin in the adjuvant setting to treat early-stage disease.
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