After Herceptin treatment, your doctor will monitor you regularly for cancer progression, advise you not to become pregnant for at least 7 months (if you are of childbearing potential), and test your heart every 6 months for at least 2 years, because there is a higher risk of developing long-term heart damage in people who take Herceptin.
Seek emergency medical help if you’re taking Herceptin and you develop any symptoms of heart failure. They include:
- shortness of breath
- trouble breathing
- an irregular or rapid heartbeat
- increased cough
- swelling of the lower legs or feet.
During treatment with Herceptin, your doctor will test your heart every 3 months.
People who can become pregnant are advised to use contraception during their treatment period and for 7 months after treatment with Herceptin ends because Herceptin may cause low levels of amniotic fluid in the baby that can lead to underdeveloped lungs and neonatal death.
A long-term study that followed women with early-stage HER2-positive breast cancer for 8-plus years, reported that adding Herceptin to chemotherapy significantly improved the overall and disease-free survival. There was a 37 percent improvement in survival and a 40 percent reduction in risk of cancer occurrence, compared to patients treated with chemotherapy alone. There was also no increase in the incidence of secondary cancers and only a minor increase in heart problems.
In terms of overall survival, in people given Herceptin plus chemotherapy for breast cancer treatment:
- 6.78% more patients are still disease-free than those just assigned chemotherapy
- The overall estimated median survival is 7.5% higher in the Herceptin with chemotherapy group.
When Herceptin plus chemotherapy was given for Metastatic breast cancer, there was:
- 2.7 months longer median time to disease progression compared to the chemotherapy group
- 2.5 months longer median duration of response compared to the chemotherapy group
- 4.8 months longer median survival compared to the chemotherapy group.
When Herceptin plus chemotherapy is given for Metastatic Gastric Cancer treatment, there were:
- 6.2% fewer deaths compared to chemotherapy.
Treatment with Herceptin usually lasts 6 months to 1 year when it is used for early HER2+ breast cancer, or it is given until disease progression or intolerable side effects occur when it is given for HER2+ metastatic breast cancer or metastatic gastric cancer.