What is targeted therapy for HER2 positive breast cancer? Targeted therapy is a kind of cancer treatment designed to aim at a specific feature of the cancer cells. For HER2 positive breast cancer, that feature is a protein called HER2, and medicines have been developed that find it and interfere with it.
These treatments changed the outlook for this type of breast cancer a great deal. This guide explains in general terms how HER2 targeted medicines work, how they are given, the side effects to know about, and how they fit with surgery and chemotherapy.
Targeted Therapy for HER2 Positive Breast Cancer: What It Means
Most cancer treatments affect both cancer cells and some healthy cells, which is why side effects happen. Targeted therapy tries to be more precise: it looks for a marker found mainly on the cancer and attacks that marker or the signals connected to it.
In HER2 positive breast cancer, the cancer cells make too much of the HER2 protein, which tells them to grow and divide. Around one in five breast cancers is HER2 positive. Targeted medicines focus on that extra HER2 activity, which is why testing for HER2 is such an important part of diagnosis.
The word targeted can sound as if treatment has no side effects at all, which is not the case. Healthy cells can be affected too, especially where HER2 plays a small normal role, but the effects are usually different from those of chemotherapy.
How HER2 Targeted Medicines Work in General Terms
There are several kinds of HER2 targeted medicines, and they work in different ways. Some are laboratory made antibodies that attach to HER2 on the surface of the cancer cell and block the growth signals, while also flagging the cell for the immune system.
Others are smaller medicines that get inside the cell and switch off the signals HER2 sends. Another kind links an antibody to a chemotherapy drug, so the chemotherapy is carried mainly to cells with HER2 on them. Your team will explain which kinds are part of your plan and why.
How and When This Treatment Is Given
Many HER2 targeted medicines are given as a drip into a vein at a treatment center, often every few weeks, while some are taken as tablets at home. The setting and rhythm depend on the medicine and on what other treatment you are having.
Treatment may start before surgery, alongside chemotherapy, to shrink the cancer, or after surgery to lower the chance of it returning. For many early stage cancers, the targeted part of treatment continues for about a year in total, though plans vary and your team will confirm the schedule for you. Appointments also give your team the chance to check blood tests and your heart, and to adjust the plan if side effects build up.
Using Targeted Therapy With Chemotherapy and Surgery
Targeted therapy rarely works alone. It is usually one part of a combined plan that can include chemotherapy, surgery, radiation, and hormone therapy if the cancer is also hormone receptor positive. Each part does a different job, and the order is planned carefully.
When targeted therapy and chemotherapy are given before surgery, doctors can see how the cancer responds by measuring it at the operation. That response gives useful information about what further treatment may help. Surgery remains a central part of treatment for most early stage HER2 positive cancers.
Common Side Effects and Heart Monitoring
Side effects vary between medicines. Common ones can include diarrhea, tiredness, nausea, skin rash, and flu like feelings such as fever or chills in the day or two after a drip. Many side effects are milder than those of chemotherapy alone, but they should always be reported.
One effect doctors watch carefully is on the heart, because HER2 targeted medicines can sometimes weaken the heart muscle. For this reason, your heart is usually checked with a scan before treatment starts and at intervals during it. If the heart weakens, treatment may be paused or changed while the heart recovers.
Questions to Ask About Your Own Plan
Good questions include asking which targeted medicines are planned for you, how they are given, and how long treatment is expected to last. It also helps to ask how your heart will be monitored, which side effects should prompt a phone call, and who to contact between appointments.
If the plan includes treatment before surgery, ask how response will be measured and what the possible next steps are. Understanding the shape of the plan ahead of time can make each stage feel more manageable. Bringing a notebook or a family member to appointments can help you keep track of the answers.
Frequently Asked Questions
Is targeted therapy the same as chemotherapy?
No. Chemotherapy attacks cells that divide quickly throughout the body, while targeted therapy aims at a specific feature of the cancer. The two are often given together for HER2 positive breast cancer, because they can work well in combination.
Does targeted therapy cause hair loss?
On its own, targeted therapy does not usually cause the full hair loss linked with chemotherapy, though hair thinning can happen. When it is given together with chemotherapy, hair loss is more likely and comes mainly from the chemotherapy part of the plan.
How will I know if the treatment is working?
Your team will follow your progress with examinations and scans, and if treatment is given before surgery, the tissue removed at the operation shows how the cancer responded. After surgery, the aim is prevention, and regular follow up appointments watch for any sign of return.
A Note on Medical Information
The information on this website is for general educational purposes only and is not medical advice. It does not replace the advice, diagnosis, or treatment of a qualified healthcare professional. If you notice a change in your breast or have concerns about your health, please contact a healthcare professional promptly.