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Systemic Treatments for ILC: Chemotherapy, Hormonal Therapy, Targeted Therapies, Immunotherapy

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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 ILC coming back.


Chemotherapy medicines are often given by IV infusion, which means the medicine is delivered directly into your bloodstream through an IV or a port. Other chemotherapy medicines are taken by mouth in the form of a pill. Two or more chemotherapy medicines 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 the ILC 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.

Some examples of the many chemotherapy medicines that may be used to treat invasive lobular carcinoma are:

  • Adriamycin (chemical name: doxorubicin)
  • Ellence (chemical name: epirubicin)
  • Cytoxan (chemical name: cyclophosphamide)
  • Taxotere (chemical name: docetaxel)
  • Taxol (chemical name: paclitaxel)
  • Xeloda (chemical name: capecitabine)
  • Ixempra (chemical name: ixabepilone)
  • methotrexate
  • fluorouracil (also called 5-fluorouracil or 5-FU)

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 also will 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.

Tests to determine the need for chemotherapy

If the cancer is small, early-stage, has not spread to the lymph nodes, and you will be taking hormonal therapy (see below), you may wonder whether chemotherapy is really necessary. You and your doctor can discuss whether or not chemotherapy is right for your situation. You also may be eligible for a genomic test, which is used to predict how likely the cancer is to recur (come back). Genomic tests look at certain genes in the cancer tumor to assess the risk of recurrence. Visit the Breast Cancer Tests page for more information about each test.

Doctors do not automatically order genomic testing for every breast cancer. Instead, they typically reserve these tests for people who have early-stage breast cancer that has not spread to the lymph nodes, or to just a few; or have ductal carcinoma in situ (DCIS). If you fit these criteria, you and your doctor can decide if genomic testing is right for you.

Hormonal therapy

If the cancer tested positive for hormone receptors, as is often the case with ILC, your doctor likely will recommend some form of hormonal therapy. In some cases of advanced-stage ILC, hormonal therapy can be given before surgery to help shrink the cancer. Still, it’s more common for hormonal therapy to start 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 don’t receive the instructions to grow and divide 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. Two types of hormonal therapy are most frequently used:

  • Selective estrogen receptor modulators (SERMs). The best-known SERM is tamoxifen. Tamoxifen acts like estrogen and attaches to the receptors on the breast cancer cells, taking the place of real estrogen. As a result, the cells don’t receive the signal to grow. Other examples of SERMs are Evista (chemical name: raloxifene) and Fareston (chemical name: toremifene). Tamoxifen can be used to treat both pre- and postmenopausal women.
  • Aromatase inhibitors. The aromatase inhibitors are:
    • Arimidex (chemical name: anastrozole)
    • Aromasin (chemical name: exemestane)
    • Femara (chemical name: letrozole)

    Aromatase inhibitors reduce the amount of estrogen your body produces. Aromatase inhibitors are most commonly used to treat postmenopausal women, but can be used to treat premenopausal women who are also taking medicine to shut down their ovaries.

Other types of hormonal therapy include the following:

  • Estrogen receptor downregulators (ERDs). ERDs destroy the estrogen receptors in cells, which prevents the estrogen from getting its message through. Faslodex (chemical name: fulvestrant) is an ERD used to treat postmenopausal women diagnosed with advanced-stage or metastatic breast cancer.
  • Ovarian shutdown or removal. The ovaries are the main source of estrogen in women before menopause. Shutting the ovaries down temporarily (for a set period of time), or even permanently, can reduce the amount of estrogen in the body.

    Ovarian shutdown methods include:

    • Medicines such as Zoladex (chemical name: goserelin) and Lupron (chemical name: leuprolide), given by injection once a month for several months to stop the ovaries from producing estrogen
    • Surgery to remove the ovaries, called oophorectomy.

Targeted therapies

Targeted cancer therapies are treatments that target specific characteristics of cancer cells, such as a protein that allows the cancer cells to grow in a rapid or abnormal way. Targeted therapies are generally less likely than chemotherapy to harm normal, healthy cells. Some targeted therapies are antibodies that work like the antibodies made naturally by our immune systems. These types of targeted therapies are sometimes called immune targeted therapies.

Targeted therapies that may be used to treat ILC are:


Immunotherapy medicines use the power of your body’s immune system to attack cancer cells.

The immune checkpoint inhibitor immunotherapy medicine Keytruda (chemical name: pembrolizumab) may be used to treat ILC.

Keytruda is used in combination with chemotherapy to treat unresectable locally advanced or metastatic triple-negative, PD-L1-positive breast cancer. Unresectable means that the cancer can’t be removed with surgery.

Keytruda also is used in combination with chemotherapy before surgery, and then on its own after surgery to treat early-stage triple-negative breast cancer with a high risk of recurrence (the cancer coming back).

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