Is Chemo Necessary for HER2 Positive?

The HER2 protein is a kind of receptor found on the surface of breast cells. Chemotherapy is typically used to shrink a tumor before it is removed from the breast with surgery.

Breast cancer is the most common cancer affecting women in the United States. Breast cancer is divided into two types based on the type of proteins that are present in the breast cells

1. Human epidermal growth factor receptor 2 (HER2)-positive breast cancer
2. HER2-negative cancer or hormone-receptive breast cancer (either estrogen-receptive or progesterone-receptive cancer)

The HER2 protein is a kind of receptor found on the surface of breast cells. It is involved in the normal growth of breast cells. There is a HER2 gene that controls the production of the HER2 protein. When there is a defect in this gene, it makes more than the required copies of the HER2 protein. Excess of HER2 protein results in overgrowth of breast cells, giving rise to HER2-positive cancer.

When you have been diagnosed with breast cancer, doctors check if you have HER2-positive breast cancer or HER2-negative cancer. The type of breast cancer is diagnosed based on tests that check for the presence of HER2 protein in the breast tissue. If the test is positive, it means you have HER2-positive cancer, and if the test results are negative, it means you have HER2-negative cancer.

About one in five women with breast cancer have HER2-positive breast cancer.

Treatment of HER2-positive cancer will depend on your overall health, age and specific needs. Doctors will discuss various cancer treatment options, including medications, with you and come up with a treatment plan tailored to your needs.

 The typical treatment for HER2-positive cancer includes

• Neoadjuvant therapy: This involves administering medications to reduce tumor size before the removal of the breast cancer tissue with surgery. This typically includes chemotherapy and other biologicals.
• Surgery
  • Breast-conserving surgery (removal of only the cancerous breast tissue)
  • Mastectomy (removal of the whole breast that contains cancer)
• Adjuvant therapy: This may be either medications or radiation therapy given after surgery to destroy the remaining cancer cells, if any. The medications may be the ones used in chemotherapy and targeted therapy.

Chemotherapy involves the use of anticancer medications that kill cancer cells present in any part of the body. The medications can be given in the form of intravenous (IV) therapy or as oral pills. It is given in cycles of two to three weeks for three to six months. The total period and the type of medications depend on how well you tolerate the therapy. There is a gap between two cycles to recover from the chemotherapy.

Targeted therapy in HER2-positive cancer refers to the drugs directed at HER-2 proteins or receptors. Hence, it is also known as HER2-directed therapy. The therapy is typically initiated after the course of chemotherapy is completed.

Chemotherapy is typically used to shrink a tumor before it is removed from the breast with surgery. This is especially necessary when

• The tumor is so large that it cannot be removed by surgery. Once the tumor regresses with chemotherapy, it becomes easier for doctors to remove it without the risk of spreading to adjacent organs.
• Doctors want to check how well a particular medication works on your breast cancer. This helps them decide whether to continue the same drug after surgery or switch to another medication in case the previous one does not work.

Everyone’s breast cancer varies at the molecular level. The type of medications your oncology team prescribes will depend on what results are expected out of your treatment and the features of your cancer.