Trastuzumab, or Herceptin (brand name), is a drug used for treating some types of stomach cancer and breast cancer. It has been approved by the FDA for the treatment of early stages of breast cancer, specifically HER2+ (Epidermal growth factor Receptor 2-positive) cancer. It is recommended for women whose cancer may or may not have spread to the lymph nodes. It may also be used for cancer that are of the estrogen receptor/progesterone receptor (ER/PR)-negative type if there is no lymph node involvement. There some common minor side effects but also serious effects on heart, lung and pregnancy, which are rare.
Common Side Effects
As with other drugs used to treat cancer, Herceptin has some side effects. Forty-percent of women treated with this drug experience symptoms similar to flu, which include:
- fever
- muscle aches
- chills
- nausea
However, side effects become less severe usually after the initial treatment. A treatment team monitors your condition during drug infusions, especially at the first dose. They may adjust infusion to reduce your discomfort. Side effects may be greater when you receive Herceptin every three weeks.
Infusion Reactions
Some patients experience major infusion reactions, which can lead to death. Symptoms may occur within 24 hours of treatment. Your doctor will monitor these symptoms and may stop the infusions if you experience breath shortness.
Your doctor may stop treatment with Herceptin if you experience:
- Severe allergic reactions
- Swelling
- Swelling of lungs
- Lung problems
- Severe breath shortness
Symptoms of Infusion reaction consist of:
- Fever, chills
- Pain
- Nausea, Vomiting
- Dizziness
- Headache
- Breath Shortness
- Drop in blood pressure
- Rashes
- Weakness
Heart Side Effects
Heart Problems
Some Herceptin side effects may involve the heart, with or without symptoms. Herceptin treatment may lead to reduction of heart function, which may not manifest with symptoms initially, or to congestive heart failure, which can cause many symptoms.
The severity and risk of heart problems related to Herceptin treatment are usually highest in patients who receive both Herceptin and another chemotherapeutic drug (anthracycline), which can lead to weak heart muscles.
Serious heart problems may include:
- Reduced heart function
- High blood pressure
- Irregularity in heartbeats
- Major heart attacks
- Death
The doctor may stop Herceptin therapy when you have signs of weakening heart muscles or other serious changes in the heart.
Monitor Your Heart
Your heart function will be monitored by the doctor before and during treatments. He may also evaluate your heart function after adjuvant therapy for breast cancer. Tests may include MUGA scan or echocardiogram. Should your treatment be stopped, the doctor will continue monitoring your heart function.
Lung Side Effects
Herceptin treatment can cause serious lung problems, which can be fatal. These include:
- Severe breath shortness
- Fluid in the lungs
- Weakening of the pulmonary valve between heart and lungs
- Severe lack of oxygen
- Swelling of lungs
- Lung scarring
These serious problems may occur after Herceptin infusion and the doctor must stop your treatment.
Side Effects on Pregnancy and Breastfeeding
Herceptin treatment on a pregnant patient can harm an unborn baby, and in some cases, it may cause death of the fetus. Some doctors recommend practicing birth control while receiving treatment with Herceptin. This may also be done for at least six months after taking Herceptin treatment.
Nursing mothers may be advised to stop nursing or to stop treatments with Herceptin.
Pregnant women who are exposed to Herceptin may call 1 (800) 690-6720 to enroll in the MotHER Pregnancy Registry.
Final Notes
Herceptin may be an effective way to treat some types of early breast cancer. Risk for Herceptin side effects is rare (less than one percent). Most of the life-threatening reactions may occur during infusion or within 24 hours after the first infusion dose. In a few cases, reactions may occur a few days after the initial dose.
Lung reactions may be more severe if the patient has an existing lung disease (ex. asthma) or if the cancer has spread to the lungs.
Patients who tolerate Herceptin treatments are unlikely to develop serious reactions in their succeeding treatments with the drug. Although major side effects are rare, the doctor will check your condition before and during treatments.