Unlike local treatments, which focus on the area (or areas) where the invasive lobular carcinoma (ILC) was found, systemic treatments involve the entire body. Treatments such as chemotherapy, hormonal therapy, and other targeted therapies are used to destroy any cancer cells that may have left the original tumor, as well as to reduce the risk of the invasive lobular carcinoma coming back.
Chemotherapy involves taking anti-cancer medicines by injection directly into a vein or by mouth in the form of a pill. Two or more chemotherapy medications are often given in combination. The medicines travel through the bloodstream to all parts of the body. As chemotherapy damages the cancer cells, it also can damage some of the body’s healthy cells, which is why you may experience side effects.
If an invasive lobular carcinoma is larger than 1 centimeter in diameter and/or has spread to the lymph nodes, chemotherapy is usually recommended or, at the very least, seriously considered. When chemotherapy is given after surgery, it is called adjuvant therapy. In cases where the tumor is large or has spread to many lymph nodes or other parts of the body, chemotherapy may be given before surgery to shrink the cancer. This approach is called neoadjuvant therapy. In either case, chemotherapy will be given in cycles, usually with a day (or days) of treatment followed by a period of “off” days. The exact schedule can vary depending on the medication or medications used. An entire course of chemotherapy usually takes about 3 to 6 months.
Just some examples of the many chemotherapies that may be used to treat invasive lobular carcinoma include:
You and your doctor will work together to determine which chemotherapy treatments are best for your situation. This can depend on the features of the cancer and any other health conditions you may have. For example, if you have a history of heart disease or heart-related risk factors, you and your doctor may want to avoid medications that can affect the heart. Your decision will also be influenced by whether or not the tumor tested positive for HER2 receptors. Some chemotherapies, such as Taxol and Cytoxan, are more commonly used with Herceptin (chemical name: trastuzumab) in treating HER2-positive breast cancers.
If you have a small, early-stage invasive lobular carcinoma that did not spread to the lymph nodes and you will be taking hormonal therapy (see next section), you may wonder whether chemotherapy is really necessary as well. You and your doctor can discuss whether or not chemotherapy is right for your situation. You also may be eligible for one of two new tests, called Oncotype DX and MammaPrint, which are being used to predict how likely the cancer is to recur (come back). Both tests, called genomic assays, look at certain genes in the tumor to assess the risk of recurrence. A “high-risk” result is often seen as good reason to go ahead and proceed with chemotherapy.
Clinical trials of Oncotype DX and MammaPrint are now under way. For example, a National Cancer Institute clinical trial called TAILORx (Trial Assigning Individualized Options for Treatment) is enrolling over 10,000 women in the United States and Canada. The study is designed to find out if women with Oncotype DX scores in the 11 to 25 range — low to intermediate risk of recurrence — benefit from having chemotherapy in addition to hormonal therapy.
Talk to your doctor if you think you may be eligible for Oncotype DX and you feel it could help in your decision-making. Although the test is expensive and not always covered by health insurance, you may be able to get coverage for it. Please visit the Oncotype DX page for more information.
If the cancer tested positive for hormone receptors, as is often the case with invasive lobular carcinoma, your doctor likely will recommend some form of hormonal therapy. In some cases of advanced ILC, hormonal therapy can be given before surgery to help shrink the tumors. Usually, though, hormonal therapy starts after other treatments such as chemotherapy or radiation therapy, unless these treatments aren’t needed.
Hormone receptors are special proteins found on the surface of certain cells throughout the body, including breast cells. These receptor proteins are the “eyes” and “ears” of the cells, receiving messages from the hormones in the bloodstream and then telling the cells what to do. In other words, the receptors act like an on-off switch for a particular activity in the cell. If the right substance comes along that fits into the receptor — like a key fitting into a lock — the switch is turned on and a particular activity in the cell begins.
When breast cells have hormone receptors, estrogen and/or progesterone can attach to those receptors and tell the cell to grow and divide. Many breast cancer cells have high numbers of receptors for estrogen, progesterone, or both. This means that when these hormones are present, the cells receive a strong message to keep growing and dividing — and this creates more cancer. If you take the hormone away or block it, the cancer cells lose their “growth fuel” and are less likely to survive.
Hormonal therapy, also called anti-estrogen therapy, works by lowering the amount of estrogen in the body or blocking the estrogen from signaling breast cancer cells to grow. You and your doctor will work together to decide which form of hormonal therapy is best in your situation. There are two types of hormonal therapy that are most frequently used:
Other types of hormonal therapy include the following:
If an invasive lobular carcinoma is HER2-positive, then its cells make too much of a protein called HER2, and they also have too many HER2 receptors at the cell surface. With too many receptors, breast cancer cells pick up too many growth signals and start growing too much and too fast. One way to slow down or stop the growth of the cancer cells is to block the receptors at the cell surface so they don't pick up as many growth signals. That’s what the medication called Herceptin (chemical name: trastuzumab) does.
Herceptin works at the cancer cell’s surface to block the chemical signals that can stimulate the cells’ uncontrolled growth. Herceptin can be used to treat the 1 out of 4 breast cancers that are HER2-positive. Treatment is usually given intravenously (through a needle that is inserted into a vein) every week for 52 weeks after surgery. In some cases of advanced invasive lobular carcinoma, Herceptin may be given before surgery to help shrink the tumors. Herceptin can cause damage to the heart, so it may not be recommended for people with heart conditions or heart-related risk. Herceptin also generally cannot be given with other chemotherapy medications that can affect the heart.
Tykerb (chemical name: lapatinib) is a newer form of anti-HER2 therapy that works inside the cell, rather than at the cell surface as Herceptin does. Inside HER2-positive breast cancer cells, HER2 receptors use protein signals, called kinases, to cause the cell to grow and divide abnormally. Kinases control how much energy the cells have to grow and multiply. Breast cancer cells that overexpress HER2 can have too much kinase activity, so the cancer cells grow too much, too fast. Tykerb works by interfering with HER2-related kinases inside the cell, limiting the amount of energy breast cancer cells have to grow and multiply.
Tykerb is taken by mouth rather than intravenously (through a vein). Right now, Tykerb can be used in combination with the chemotherapy medication Xeloda (chemical name: capecitabine) to treat advanced, HER2-positive breast cancer that has stopped responding to other Herceptin-chemotherapy combinations.
Like hormonal therapy and HER2-targeted therapies, other targeted therapies are designed to interfere with a certain process that enables breast cancer cells to grow and thrive. This is an active area of research in breast cancer treatment.
Just one example is Avastin (chemical name: bevacizumab), a medication that targets a protein called VEGF, or vascular endothelial growth factor. VEGF plays a key role in stimulating the process cancer cells use to create new blood vessels, which is known as angiogenesis. Cancer cells have to create new blood vessels so they can get the oxygen and nutrients they need to grow and thrive. Avastin works by attaching itself to VEGF, which can prevent it from stimulating the formation and growth of new blood vessels.
Avastin can be used in combination with a chemotherapy medication called Taxol (chemical name: paclitaxel) to treat advanced breast cancer.
These and other forms of targeted therapy are still under investigation in clinical trials. For more information, visit the Targeted Therapies section. You also may wish to visit our Clinical Trials section.
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