MyBCTeam members often celebrate finishing their initial chemotherapy regimens and beginning maintenance therapy. “Congrats on getting the chemo done!” offered one member to another. “The maintenance treatments go so much faster, and you will start getting more of your energy back.”
In HER2-positive breast cancer, cancer cells make large amounts of a protein called human epidermal growth factor receptor 2 (HER2). This type of breast cancer requires HER2 to continue growing, so it’s vulnerable to treatments that target this protein.
HER2-positive breast cancer has a high risk of recurrence (coming back) and metastasis (spreading to other parts of the body). But new targeted maintenance treatments have extended both progression-free survival (time until cancer worsens) and overall survival (how long a person lives). This means that it’s critical to stick with your maintenance therapy to get the best results from your treatment. Your whole breast cancer care team, including your medical oncologist, nurse navigator, and oncology treatment nurse, is there to support you through this important phase of treatment.
People starting maintenance therapy for HER2-positive breast cancer naturally have questions about how long this phase of treatment will last and what to expect.
Maintenance therapy is given to help keep cancer that disappeared after initial therapy from coming back. Initial treatment for HER2-positive breast cancer may include:
Regardless of your stage at diagnosis, your oncology care team will likely recommend starting maintenance therapy right after your initial treatment. Maintenance therapy may simply mean continuing one or two medications that you took for your first treatment.
The goal of maintenance therapy is to maintain remission — to prevent or delay the cancer’s return. Complete remission (also called complete response) means that after treatment, no signs of cancer remain.
Sometimes, cancer reaches partial remission (partial response), which means that treatment reduced the tumor’s size or the cancer’s spread but did not kill all the cancer cells. In this case, maintenance therapy is also called “continuous therapy” because it is used continuously to keep cancer from progressing. Another goal of continuous maintenance therapy is to minimize the use of chemotherapy.
Maintenance therapy for HER2-positive breast cancer usually means taking at least one targeted drug designed to block the activity of the HER2 protein. The most common of these medications are trastuzumab (Herceptin) and pertuzumab (Perjeta). Both medications are anti-HER2 monoclonal antibodies, a type of laboratory-made protein that recognizes HER2 and stops it from sending growth signals to the cancer cells. These drugs are commonly combined.
Targeted medications can be given through either IV infusion into a vein or an injection under the skin. IV infusions can take hours, whereas injections are delivered more quickly. Both infusions and injections need to be given by an oncology treatment nurse, usually at an infusion center, but sometimes a nurse can do the injection at your home. Both the IV and injected forms are typically given once every three weeks. Your oncology nurse can help answer questions related to treatment administration.
Nurses are a vital part of your breast cancer care team and perform many important roles. Nurse navigators can help you navigate a new diagnosis, make appointments, and help you access other services you may require. Oncology treatment nurses administer maintenance treatments and provide support. Nurses can also answer many of your questions about maintenance therapy.
Some breast cancers that are positive for HER2 are also positive for proteins called hormone receptors. Hormone receptor-positive (HR-positive) cancers include estrogen receptor-positive and progesterone receptor-positive cancers. About half of HER2-positive breast cancers are also HR-positive.
Additional maintenance therapy options that may be recommended for this HR-positive subgroup include neratinib (Nerlynx), a kinase inhibitor pill taken once a day, and endocrine therapy, a hormone-targeted therapy given as a daily pill for up to 10 years. Endocrine therapy may be recommended instead of trastuzumab or combined with it.
Maintenance therapy is taken long term, but exactly how long depends on the severity or stage of your cancer.
For cases of breast cancer in stages 0 through 3, maintenance treatment is usually given after a chemotherapy regimen such as paclitaxel (Taxol). After the final dose of chemotherapy, maintenance therapy is typically continued for another six months, for a total of 12 months.
A meta-analysis of five studies with more than 12,000 participants found that stopping trastuzumab maintenance therapy after one year was safer than stopping after six months. Taking trastuzumab maintenance therapy for longer than one year, however, was associated with increased cardiotoxicity, or damage to the heart, a rare but serious side effect of trastuzumab. Talk to your oncology care nurse if you have any concerns about your risk for heart problems during maintenance treatment.
According to the American Society of Clinical Oncology (ASCO) guidelines, maintenance therapy is a lifelong treatment for advanced or metastatic breast cancer. If the cancer progresses, you and your doctor will discuss switching treatments. If side effects become difficult to manage, talk to your oncology nurse about options.
To minimize the risk of congestive heart failure associated with trastuzumab, your doctor may want to do routine tests that check your heart function. This is especially important if you smoke or have a preexisting heart condition. If you are taking certain endocrine therapies, which may contribute to bone loss, you may also need bone density testing. You can ask your nurse navigator for help scheduling this testing.
How often you’ll need to follow up with your doctor or oncology nurse depends on the stage of your cancer, what treatments you are getting, and how well your cancer is responding.
A person in complete remission may continue to have follow-up visits with their oncologist or cancer care nurse. Yearly mammography is the only screening that ASCO and the American College of Physicians recommend for people in complete remission with no new or returning symptoms.
A person in partial remission or with new or returning symptoms of cancer will need more frequent follow-ups. Doctors will look for new or remaining tumors and determine where they are located and how they are responding to treatment. People who have just completed treatments will also have more frequent follow-ups for the next five years.
Talk with your doctor or nurse if you have symptoms that suggest your cancer may have returned, such as:
The same types of tests used to initially diagnose breast cancer — such as imaging tests, blood tests for tumor markers, and biopsy — may be done to confirm whether the cancer is back. Always speak with your oncology care team about your symptoms, treatment side effects, and concerns. Your oncology care team can discuss your treatment options and work with you to decide on the best treatment for you.
On MyBCTeam, the social network for people with breast cancer and their loved ones, more than 58,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.
Are you or a loved one living with HER2-positive breast cancer? Is maintenance therapy part of your treatment plan? Share your experience in the comments below, or start a conversation by posting on your Activities page.