How do we treat Breast Cancer?

If you’ve been diagnosed with breast cancer, your cancer care team will discuss your treatment options with you. It’s important that you think carefully about each of your choices. Weigh the benefits of each treatment option against the possible risks and side effects.

Breast Cancer is treated by a team. Based on your situation, different types of specialists may be involved in your care. These could include:

  • A breast surgeon or surgical oncologist: a doctor who uses surgery to treat breast cancer
  • A radiation oncologist: a doctor who uses radiation to treat cancer
  • A medical oncologist: a doctor who uses chemotherapy and other medicines to treat cancer
  • A plastic surgeon: a doctor who specializes in reconstructing or repairing parts of the body

You might have many other specialists on your treatment team as well, including Genetic Counselors, physician assistants (PAs), Lymph therapists, nurses, psychologists, nutritionists, social workers, and other health professionals.

Local treatments

Some treatments are local, meaning they treat the tumor without affecting the rest of the body. 

Most women with breast cancer will have some type of surgery to remove the tumor. Depending on the type of breast cancer and how advanced it is, you might need other types of treatment as well, either before or after surgery, or sometimes both.

Systemic treatments

Drugs used to treat breast cancer are considered systemic therapies because they can reach cancer cells almost anywhere in the body. They can be given by mouth or put directly into the bloodstream. Depending on the type of breast cancer, different types of drug treatment might be used, including:

Surgery for Breast Cancer

Most women with breast cancer will require surgery as part of their treatment. There are several different options and a mastectomy is not the standard of care any longer. Surgery aims to:

  • Remove the cancer fully
  • Determine whether the cancer had spread to lymph nodes under the arm (sentinel lymph node biopsy or axillary lymph node dissection)
  • Restore a natural shape to the breast including symmetry between the two sides (breast reconstruction)
  • Relieve symptoms of advanced cancer such as ulcerating or bleeding from the cancer

Our team will consider the type of operation based on your breast cancer, and your family and medical history and your body shape but you will have an input into which operation to have. It’s important tobe informed about your options, why some options are appropriate and others not and what the advantages migh be of one over another. We are here to help make the best choice for you.

Removing the Cancer

There are two main types of surgery to remove breast cancer:

  • Breast-conserving surgery (also called a lumpectomy, quadrantectomy, partial mastectomy, or segmental mastectomy) is a surgery in which only the part of the breast containing the cancer is removed. The goal is to remove the cancer as well as some surrounding normal tissue. How much breast is removed depends on where and how big the tumor is, as well as other factors.
  • Mastectomy is a surgery in which the entire breast is removed, including all of the breast tissue and sometimes other nearby tissues. There are several different types of mastectomies. Some women may also get a double mastectomy, in which both breasts are removed.

Choosing between mastectomy and Breast conservation

Most women with early-stage breast cancers can choose between breast-conservation surgery (BCS) and mastectomy. The main advantage of BCS is that a woman keeps most of her breast but radiation will be required after surgery.

Women who have mastectomy for early-stage cancers are less likely to need radiation.

For some women, mastectomy may be a better option, because of the type of breast cancer, the large size of the tumor, previous treatment with radiation, or certain other factors.

Some women might worry that having a less extensive surgery might raise their risk of the cancer coming back, but studies following thousands of women for more than 20 years show that when BCS is done with radiation, survival is the same as having a mastectomy in people who are candidates for both types of surgery.

 

Surgery to remove nearby lymph nodes

To find out if the breast cancer has spread to underarm (axillary) lymph nodes, one or more of these lymph nodes will be removed and looked at in the lab. This is an important part of figuring out the stage (extent) of the cancer. Lymph nodes may be removed either as part of the surgery to remove the breast cancer or as a separate operation.

The two main types of surgery to remove lymph nodes are:

  • Sentinel lymph node biopsy (SLNB) is a procedure in which the surgeon removes only the lymph node(s) under the arm where the cancer would likely spread first. Removing only one or a few lymph nodes lowers the risk of side effects from the surgery, such as arm swelling that is also known as lymphedema.
  • Axillary lymph node dissection (ALND) is a procedure in which the surgeon removes many (usually less than 20) underarm lymph nodes. ALND is not done as often as it was in the past, but it might still be the best way to look at the lymph nodes in some situations.

Breast reconstruction after surgery

Many woman having surgery for breast cancer might have the option of breast reconstruction. A woman having a mastectomy might want to consider having the breast mound rebuilt to restore the breast’s appearance after surgery. In some breast-conserving surgeries, a woman may consider having fat grafted into the affected breast to correct any dimples left from the surgery. The options will depend on each woman’s situation.

There are several types of reconstructive surgery, but your options may depend on your medical situation and personal preferences. You may have a choice between having breast reconstruction at the same time as the breast cancer surgery (immediate reconstruction) or at a later time (delayed reconstruction).

If you are thinking about having reconstructive surgery, it’s a good idea to discuss it with your breast surgeon and a plastic surgeon before your mastectomy or BCS. This gives the surgical team time to plan out the treatment options that might be best for you, even if you wait and have the reconstructive surgery later.

Radiation for Breast Cancer

Radiation therapy is treatment with high-energy rays (or particles) that destroy cancer cells. Some women with breast cancer will need radiation, in addition to other treatments. Radiation therapy is used in several situations:

  • After breast-conserving surgery (BCS), to help lower the chance that the cancer will come back in the same breast or nearby lymph nodes.
  • After a mastectomy, especially if the cancer was larger than 5 cm (about 2 inches), if cancer is found in many lymph nodes, or if certain surgical margins have cancer such as the skin or muscle.
  • If cancer has spread to other parts of the body, such as the bones or brain.

The main types of radiation therapy that we use to treat breast cancer are external beam radiation therapy (EBRT).

External beam radiation

This is the most common type of radiation therapy for women with breast cancer. A machine outside the body focuses the radiation on the area affected by the cancer.

Which areas need radiation depends on whether you had a mastectomy or breast-conserving surgery (BCS) and whether or not the cancer has reached nearby lymph nodes.

  • If you had a mastectomy and no lymph nodes had cancer cells, radiation is focused on the chest wall, the mastectomy scar, and the places where any drains exited the body after surgery.
  • If you had BCS, you will most likely have radiation to the entire breast (called whole breast radiation), and an extra boost of radiation to the area in the breast where the cancer was removed (called the tumor bed) to help prevent it from coming back in that area. The boost is often given after the treatments to the whole breast have ended. It uses the same machine, with lower amounts of radiation aimed at the tumor bed. Most women don’t notice different side effects from boost radiation than from whole breast radiation.
  • If cancer was found in the lymph nodes under the arm (axillary lymph nodes), this area may be given radiation, as well. In some cases, the area treated might also include the nodes above the collarbone (supraclavicular lymph nodes) and the nodes beneath the breast bone in the center of the chest (internal mammary lymph nodes).

When will my Radiation start?

If you will need external radiation therapy after surgery, it is usually not started until your surgery site has healed, which often takes a month or longer. If you are getting chemotherapy as well, radiation treatments are usually delayed until chemotherapy is complete.

Before your radiation can start, a planning session will be required. This is to program the radiation beam to treat the appropriate area.

Preparing for Radiotherapy

Before your treatment starts, the radiation team will carefully figure out the correct angles for aiming the radiation beams and the proper dose of radiation. They will make some ink marks or small tattoos on your skin to focus the radiation on the right area. Ask your health care team if the marks they use will be permanent.

External radiation therapy is much like getting an x-ray, but the radiation is stronger. The procedure itself is painless. Each treatment lasts only a few minutes, but the setup time—getting you into place for treatment—usually takes longer.

Types and schedules of external beam radiation for breast cancer

Whole breast radiation

  • The standard schedule for getting whole breast radiation is 5 days a week (Monday through Friday) for about 6 to 7 weeks.
  • Another option is hypofractionated radiation therapy where the radiation is also given to the whole breast, but in larger daily doses (Monday through Friday) using fewer treatments (typically for only 3 to 4 weeks). In women treated with breast-conserving surgery (BCS) and without cancer spread to underarm lymph nodes, this schedule has been shown to be just as good at keeping the cancer from coming back in the same breast as giving the radiation over longer periods of time. It might also lead to fewer short-term side effects.

Chest wall radiation

If you had a mastectomy and none of the lymph nodes had cancer, radiation will be given to the entire chest wall, the mastectomy scar, and the areas of any surgical drains. It is typically given daily 5 days a week for 6 weeks.

Lymph node radiation

Whether or not you have had BCS or a mastectomy, if cancer was found in the lymph nodes under the arm (axillary lymph nodes), this area may be given radiation. In certain cases, the lymph nodes above the collarbone (supraclavicular lymph nodes) and behind the breast bone in the center of the chest (internal mammary lymph nodes) will also receive radiation along with the underarm nodes. It is typically given daily 5 days a week for 6 weeks at the same time as the radiation to the breast or chest wall is given.

Accelerated partial breast irradiation

In select women, some doctors are using accelerated partial breast irradiation (APBI) to give larger doses over a shorter time to only one part of the breast compared to the entire breast. Since more research is needed to know if these newer methods will have the same long-term results as standard radiation, not all doctors use them. There are several different types of accelerated partial breast irradiation:

  • Intraoperative radiation therapy (IORT): In this approach, a single large dose of radiation is given to the area where the tumor was removed (tumor bed) in the operating room right after BCS (before the breast incision is closed). IORT requires special equipment and is not widely available.
  • 3D-conformal radiotherapy (3D-CRT): In this technique, the radiation is given with special machines so that it is better aimed at the tumor bed. This spares more of the healthy breast. Treatments are given twice a day for 5 days.
  • Intensity-modulated radiotherapy (IMRT): IMRT is like 3D-CRT, but it also changes the strength of some of the beams in certain areas. This gets stronger doses to certain parts of the tumor bed and helps lessen damage to nearby normal body tissues.
  • Brachytherapy: We do not offer this option.

Women who are interested in these approaches may want to ask their doctor about taking part in clinical trials of accelerated partial breast irradiation.

Possible side effects of external radiation

The main short-term side effects of external beam radiation therapy to the breast are:

  • Swelling in the breast
  • Skin changes in the treated area similar to a sunburn (redness, skin peeling, darkening of the skin)
  • Fatigue

Your health care team may advise you to avoid exposing the treated skin to the sun because it could make the skin changes worse. Most skin changes get better within a few months. Changes to the breast tissue usually go away in 6 to 12 months, but it can take longer.

External beam radiation therapy can also cause side effects later on:

  • Some women may find that radiation therapy causes the breast to become smaller and firmer.
  • Radiation may affect your options for breast reconstruction later on. It can also raise the risk of problems with appearance and healing if it’s given after reconstruction, especially tissue flap procedures.
  • Women who have had breast radiation may have problems breastfeeding.
  • Radiation to the breast can sometimes damage some of the nerves to the arm. This is called brachial plexopathy and can lead to numbness, pain, and weakness in the shoulder, arm, and hand.
  • Radiation to the underarm lymph nodes might cause lymphedema, a type of pain and swelling in the arm or chest.
  • In rare cases, radiation therapy may weaken the ribs, which could lead to a fracture.
  • In the past, parts of the lungs and heart were more likely to get some radiation, which could lead to long-term damage of these organs in some women. Modern radiation therapy equipment better focuses the radiation beams, so these problems are rare today.
  • A very rare complication of radiation to the breast is the development of another cancer called an angiosarcoma.

Chemotherapy for Breast Cancer

Chemotherapy (chemo) uses medication, usually given intravenously but occasionally by mouth. The drugs travel through the bloodstream to reach cancer cells in most parts of the body preventing the cells from dividing and growing. 

When do we use chemotherapy?

Not all women with breast cancer will need chemo. Chemotherapy is used where we are concerned that the risk of recurrence of the cancer is significantly high and with proof that chemo would reduce that risk. We have well defined criteria where this is indicated. 

Timing of Chemotherapy.

  • After surgery (adjuvant chemotherapy): Adjuvant chemo might be given once the main cancer has been removed to try and kill any cancer cells that might still be lurking around in the body but can’t be seen, even on imaging tests. If these cells were allowed to grow, they could form new tumors in other places in the body. Adjuvant chemo can lower the risk of breast cancer coming back.
  • Before surgery (neoadjuvant chemotherapy): Neoadjuvant chemo might be given to try and shrink the tumour so it can be removed with less extensive surgery. Because of this, neoadjuvant chemo is often used to treat cancers that are too big to be removed by surgery when first diagnosed (called locally advanced cancers). Also, by giving chemo before the tumor is removed, we can see how sensitive the cancer is to it. If the first set of chemo drugs doesn’t shrink the tumor, we may opt to change to other drugs. The intention is not only to kill the initial tumour, but any cancer cells that have spread but can’t be seen. Just like adjuvant chemo, neoadjuvant chemo can lower the risk of breast cancer coming back.  
  • For some types of breast cancer, you may be offered more chemotherapy (Extended Adjuvant chemotherapy) after surgery if there are viable tumor cells found at the time of surgery (also called residual disease). This can further reduce the chances of the cancer coming back (recurrence).
  • For advanced breast cancer: Chemo can be used as the main treatment for women whose cancer has spread outside the breast and underarm area, either when it is diagnosed or after initial treatments. The length of treatment depends on how well the chemo is working and how well you tolerate it.
  •  We offer special Molecular Tests in some types of cancers where we suspect chemotherapy might not be adding any benefit.  Tests like MammaPrint and Oncotype Dx can be used if funding is available as these tests are expensive.

How is chemotherapy given?

Chemo drugs for breast cancer are typically given into a vein (IV), either as an injection over a few minutes or as an infusion over a longer period of time. This is done in a chemotherapy suite or treatment unit.  

Because many chemotherapy drugs damage the veins while it is running in, we advise the use of a special implantable port which has a small canula which end in the larger veins behind the breast bone, avoiding the need for finding smaller veins in the arms.  They are used to put medicines, blood products, nutrients, or fluids right into your blood. These can easily be removed once no longer required.

Chemo is given in cycles, followed by a rest period to give you time to recover from the effects of the drugs. Cycles are most often 2 or 3 weeks long. The schedule varies depending on the drugs used. For example, with some drugs, the chemo is given only on the first day of the cycle. With others, it is given for a few days in a row, or once a week. Then, at the end of the cycle, the chemo schedule repeats to start the next cycle.

Adjuvant and neoadjuvant chemo is often given for a total of 3 to 6 months, depending on the drugs used. The length of treatment for advanced breast cancer depends on how well it is working and what side effects you have.

Possible side effects of chemo for breast cancer

Chemo drugs can cause side effects. These depend on the type and dose of drugs given, and the length of treatment. Some of the most common possible side effects include:

  • Hair loss
  • Nail changes
  • Mouth sores
  • Loss of appetite or weight changes
  • Nausea and vomiting
  • Diarrhea

Chemo can also affect the blood-forming cells of the bone marrow, which can lead to:

  • Increased chance of infections (from low white blood cell counts)
  • Easy bruising or bleeding (from low blood platelet counts)
  • Fatigue (from low red blood cell counts and other reasons)

These side effects usually go away after treatment is finished. There are often ways to lessen these side effects. For example, drugs can be given to help prevent or reduce nausea and vomiting.

Other side effects are also possible. Some of these are more common with certain chemo drugs. We will discuss every patients specific treatment plan in detail.

Hormone Therapy for Breast Cancer

Some types of breast cancer are affected by hormones, like estrogen and progesterone. The breast cancer cells have receptors (proteins) that attach to estrogen and progesterone, which helps them grow. Treatments that stop these hormones from attaching to these receptors are called hormone or endocrine therapy.

Hormone therapy can reach cancer cells almost anywhere in the body and not just in the breast. It’s recommended for women with tumors that are hormone receptor-positive. It does not help women whose tumors don’t have hormone receptors.

When is hormone therapy used?

Hormone therapy is often used after surgery (as adjuvant therapy) to help reduce the risk of the cancer coming back. Sometimes it is started before surgery (as neoadjuvant therapy). It is usually taken for at least 5 to 10 years.

Hormone therapy can also be used to treat cancer that has come back after treatment or that has spread to other parts of the body.

How does hormone therapy work?

About 70% of breast cancers are hormone receptor-positive. Their cells have receptors (proteins) for the hormones estrogen (ER-positive cancers) and/or progesterone (PR-positive cancers) which help the cancer cells grow and spread.

Most types of hormone therapy either lower estrogen levels or stop estrogen from binding to the breast cancer cells. Certain targeted therapy drugs can make hormone therapy even more effective.

Drugs that block estrogen receptors

These drugs work by stopping estrogen from fueling breast cancer cells to grow.

  • Tamoxifen

    This drug blocks estrogen receptors on breast cancer cells. It stops estrogen from connecting to the cancer cells and telling them to grow and divide. While tamoxifen acts like an anti-estrogen in breast cells, it acts like an estrogen in other tissues, like the uterus and the bones. Because of this, it is called a selective estrogen receptor modulator (SERM). It can be used to treat women with breast cancer who have or have not gone through menopause.

    Tamoxifen can be used in several ways:

    • In women at high risk of breast cancer, tamoxifen can be used to help lower the risk of developing breast cancer.
    • For women who have been treated with breast-conserving surgery for ductal carcinoma in situ (DCIS) that is hormone receptor-positive, taking tamoxifen for 5 years lowers the chance of the DCIS coming back. It also lowers the chance of getting an invasive breast cancer in both breasts.
    • For women with hormone receptor-positive invasive breast cancer treated with surgery, tamoxifen can help lower the chances of the cancer coming back and raise the chances of living longer. It can also lower the risk of getting a new cancer in the other breast. Tamoxifen can be started either after surgery (adjuvant therapy) or before surgery (neoadjuvant therapy) and is usually taken for 5 to 10 years. This drug is used mainly for women with early-stage breast cancer who have not yet gone through menopause. (If you have gone through menopause, aromatase inhibitors are usually used instead.)
    • For women with hormone-positive breast cancer that has spread to other parts of the body, tamoxifen can often help slow or stop the growth of the cancer, and might even shrink some tumors.

    Toremifene (Fareston) is another SERM that works in a similar way, but it is used less often and is only approved to treat metastatic breast cancer in postmenopausal women. It is not likely to work if tamoxifen has already been used and has stopped working. These drugs are pills, taken by mouth.

    Side effects of SERMs

    The most common side effects of tamoxifen and toremifene are:

    • Hot flashes
    • Vaginal dryness or discharge

    Some women with cancer spread to the bones may have a tumor flare with bone pain . This usually decreases quickly, but in some rare cases a woman may also develop a high calcium level in the blood that is hard to control. If this happens, the treatment may need to be stopped for a time.

    Rare, but more serious side effects are also possible:

    • If a woman has gone through menopause, SERMs can increase her risk of developing uterine cancer. Tell your doctor right away about any unusual vaginal bleeding (a common symptom of this cancer). Most uterine bleeding is not from cancer, but this symptom always needs prompt attention.
    • Blood clots are another uncommon, but serious side effect. They usually form in the legs (called deep vein thrombosis or DVT), but sometimes a piece of clot in the leg may break off and end up blocking an artery in the lungs (pulmonary embolism or PE). Call your doctor or nurse right away if you develop pain, redness, or swelling in your lower leg (calf), shortness of breath, or chest pain, because these can be symptoms of a DVT or PE.
    • Rarely, tamoxifen has been associated with strokes in post-menopausal women, so tell your doctor if you have severe headaches, confusion, or trouble speaking or moving.

    Depending on a woman's menopausal status, tamoxifen can have different effects on the bones. In pre-menopausal women, tamoxifen can cause some bone thinning, but in post-menopausal women it often strengthens bones to some degree. The benefits of taking these drugs outweigh the risks for almost all women with hormone receptor-positive breast cancer.

Fulvestrant (Faslodex)

Fulvestrant is a drug that blocks and damages estrogen receptors. This drug is not a SERM – it acts like an anti-estrogen throughout the body. It is known as a selective estrogen receptor degrader (SERD).  Fulvestrant is currently approved only for use in post-menopausal women. It is sometimes used “off-label” in pre-menopausal women, often combined with a luteinizing-hormone releasing hormone (LHRH) agonist to turn off the ovaries (see the section on Ovarian Ablation below).

Fulvestrant is given:

  • Alone to treat advanced breast cancer that has not been treated with other hormone therapy.
  • Alone to treat advanced breast cancer after other hormone drugs (like tamoxifen and often an aromatase inhibitor) have stopped working.
  • In combination with a CDK 4/6 inhibitor or PI3K inhibitor to treat metastatic breast cancer as initial hormone therapy or after other hormone treatments have been tried.  

It is given by injections into the buttocks. For the first month, the shots are given 2 weeks apart. After that, they are given once a month.

Side effects of fulvestrant

Common short-term side effects can include:

  • Hot flashes and/or night sweats
  • Headache
  • Mild nausea
  • Bone pain
  • Injection site pain

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Treatments that lower estrogen levels

Some hormone treatments work by lowering estrogen levels. Estrogen is produced from several sources.

For pre-menopausal women, removing or shutting down the ovaries (ovarian suppression), which are the main source of estrogen, effectively makes them post-menopausal. This may allow some other hormone therapies, such as AIs, to be used.

There are several ways to remove or shut down the ovaries to treat breast cancer:

  • Oophorectomy: Surgery to remove the ovaries. This is a form of permanent ovarian ablation.
  • Luteinizing hormone-releasing hormone (LHRH) analogs: These drugs are used more often than oophorectomy. They stop the signal that the body sends to the ovaries to make estrogen, which causes temporary menopause. Common LHRH drugs include goserelin (Zoladex) and leuprolide (Lupron). They can be used alone or with other hormone drugs (tamoxifen, aromatase inhibitors, fulvestrant) as hormone therapy in pre-menopausal women.
  • Chemotherapy drugs: Some chemo drugs can damage the ovaries of pre-menopausal women so they no longer make estrogen. Ovarian function can return months or years later in some women, but in others the damage to the ovaries is permanent and leads to menopause.

All of these methods can cause symptoms of menopause, including hot flashes, night sweats, vaginal dryness, and mood swings

For pre-menopausal women, removing or shutting down the ovaries (ovarian suppression), which are the main source of estrogen, effectively makes them post-menopausal. This may allow some other hormone therapies, such as AIs, to be used.

There are several ways to remove or shut down the ovaries to treat breast cancer:

  • Oophorectomy: Surgery to remove the ovaries. This is a form of permanent ovarian ablation.
  • Luteinizing hormone-releasing hormone (LHRH) analogs: These drugs are used more often than oophorectomy. They stop the signal that the body sends to the ovaries to make estrogen, which causes temporary menopause. Common LHRH drugs include goserelin (Zoladex) and leuprolide (Lupron). They can be used alone or with other hormone drugs (tamoxifen, aromatase inhibitors, fulvestrant) as hormone therapy in pre-menopausal women.
  • Chemotherapy drugs: Some chemo drugs can damage the ovaries of pre-menopausal women so they no longer make estrogen. Ovarian function can return months or years later in some women, but in others the damage to the ovaries is permanent and leads to menopause.

All of these methods can cause symptoms of menopause, including hot flashes, night sweats, vaginal dryness, and mood swings

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Targeted therapy for hormone receptor-positive breast cancer

 These targeted treatments can be added to other forms of hormonal treatment but they might also add to the side effects.

CDK4/6 inhibitors

Palbociclib (Ibrance)ribociclib (Kisqali), and abemaciclib (Verzenio) are drugs that block proteins in the cell called cyclin-dependent kinases (CDKs), particularly CDK4 and CDK6. Blocking these proteins in hormone receptor-positive breast cancer cells helps stop the cells from dividing. This can slow cancer growth.

These drugs are approved for women with advanced hormone receptor-positive, HER2-negative breast cancer and are taken as pills, typically once or twice a day.

There are different ways to use these drugs.

  • Any of the three drugs can be given along with an aromatase inhibitor or fulvestrant to women who have gone through menopause.
  • Any of these three drugs can also be given with fulvestrant or an aromatase inhibitor to women who are still having regular periods (premenopausal) or are almost in menopause (perimenopausal). These women, however, must also be on medicines, such as luteinizing hormone-releasing hormone (LHRH) analogs, that stop the ovaries from making estrogen.
  • Abemaciclib can also be used by itself in women who have previously been treated with hormone therapy and chemotherapy.

The most common side effects are low blood cell counts and fatigue. Nausea and vomiting, mouth sores, hair loss, diarrhea, and headache are less common side effects. Very low white blood cell counts can increase the risk of serious infection. A rare but possible life-threatening side effect is inflammation of the lungs, also called interstitial lung disease or pneumonitis.

Treatment of for HER2 positive Breast Cancer

About 20% of breast cancers, have too much of a growth-promoting protein known as HER2 on their surface. These cancers, known as HER2-positive breast cancers, tend to grow and spread more aggressively. Different types of drugs have been developed that target the HER2 protein.

Monoclonal antibodies

Monoclonal antibodies are man-made versions of immune system proteins (antibodies) that are designed to attach to a specific target. In this case, they attach to the HER2 protein on cancer cells, which can help stop the cells from growing.

Trastuzumab (Herceptin, others): Trastuzumab can be used to treat both early-stage and advanced breast cancer. This drug is often given with chemo, but it might also be used alone (especially if chemo alone has already been tried). When started before (neoadjuvant) or after (adjuvant) surgery to treat early breast cancer, this drug is usually given for 6 months to a year. For advanced breast cancer, treatment is often given for as long as the drug is helpful. This drug is given into a vein (IV).

Herceptin was the original brand name for trastuzumab, but several similar versions (called biosimilars) are now available like Ogivri.

Another type of trastuzumab, called trastuzumab and hyaluronidase injection (Herceptin Hylecta), is also available. It is given as a subcutaneous (under the skin) shot over a few minutes.

Pertuzumab (Perjeta): This monoclonal antibody can be given with trastuzumab and chemo, either before or after surgery to treat early-stage breast cancer, or to treat advanced breast cancer. This drug is given into a vein (IV).

Antibody-drug conjugates

An antibody-drug conjugate (ADC) is a monoclonal antibody linked to a chemotherapy drug. In this case, the anti-HER2 antibody acts like a homing signal by attaching to the HER2 protein on cancer cells, bringing the chemo directly to them.

Ado-trastuzumab emtansine (Kadcyla or TDM-1): This antibody-drug conjugate is used by itself to treat early-stage breast cancer after surgery (when chemo and trastuzumab were given before surgery, and there was cancer still present at the time of surgery), or to treat advanced breast cancer in women who have already been treated with trastuzumab and chemo. This drug is given in a vein (IV).

Fam-trastuzumab deruxtecan (Enhertu) (Available shortly): This antibody-drug conjugate can be used by itself to treat breast cancer that can’t be removed with surgery or that has spread (metastasized) to another part of the body, typically after at least 2 other anti-HER2 targeted drugs have been tried. This drug is given in a vein (IV).

Kinase inhibitors

HER2 is a type of protein known as a kinase. Kinases are proteins in cells that normally relay signals (such as telling the cell to grow). Drugs that block kinases are called kinase inhibitors.

Lapatinib (Tykerb): This drug is a pill taken daily. Lapatinib is used to treat advanced breast cancer, typically along with the chemo drug capecitabine or with certain hormone therapy drugs.

Neratinib (Nerlynx) : This kinase inhibitor is a pill taken daily. Neratinib is used to treat early-stage breast cancer after a woman has completed one year of trastuzumab, and it is usually given for one year. It can also be given along with the chemo drug capecitabine to treat people with metastatic disease, typically after at least 2 other anti-HER2 targeted drugs have been tried. 

Tucatinib (Tukysa): This kinase inhibitor is taken as pills, typically twice a day. Tucatinib is used to treat advanced breast cancer, after at least one other anti-HER2 targeted drug has been tried. It is typically given along with trastuzumab and the chemo drug capecitabine.

Side effects HER2 targeted therapy drugs

The side effects of HER2 targeted drugs are often mild, but some can be serious. Discuss what you can expect with your doctor.

The monoclonal antibodies and antibody-drug conjugates can sometimes cause heart damage during or after treatment. This can lead to congestive heart failure. For most (but not all) women, this effect lasts a short time and gets better when the drug is stopped. The risk of heart problems is higher when these drugs are given with certain chemo drugs that also can cause heart damage, such as doxorubicin (Adriamycin) and epirubicin (Ellence). Because these drugs can cause heart damage, doctors often check your heart function (with an echocardiogram or a MUGA scan) before treatment, and regularly while you are taking the drug. Let your doctor know if you develop symptoms such as shortness of breathleg swelling, and severe fatigue.

Lapatinib, neratinib, tucatinib, and the combination of pertuzumab with trastuzumab can cause severe diarrhea, so it’s very important to let your health care team know about any changes in bowel habits as soon as they happen.

Lapatinib and tucatinib can also cause hand-foot syndrome, in which the hands and feet become sore and red, and may blister and peel.

Lapatinib, neratinib, and tucatinib can cause liver problems. Your doctor will do blood tests to check your liver function during treatment. Let your health care team know right away if you have possible signs or symptoms of liver problems, such as itchy skin, yellowing of the skin or the white parts of your eyes, dark urine, or pain in the right upper belly area.

Fam-trastuzumab deruxtecan (Enhertu) can cause serious lung disease in some women. In some cases this might even be life threatening. It’s very important to let your doctor or nurse know right away if you’re having symptoms such as coughing, wheezing, trouble breathing, or fever.  

If you are pregnant, you should not take these drugs. They can harm and even cause death to the fetus. If you could become pregnant, talk to your doctor about using effective birth control while taking these drugs.

Panorama Centre for Surgical Oncology