Can HER2-Positive Breast Cancer Be Cured?

HER2-positive breast cancer is associated with cancer cells that have extra copies of the HER2 gene and produce extra HER2 receptor proteins. With recent advances in medicine, it is considered that HER2-positive breast cancer is curable.

With recent advances in medicine, it is considered that HER2-positive breast cancer is curable. Targeted therapy is used to cure HER2-positive breast cancer. However, surgery, radiation therapy, chemotherapy and hormonal therapy may also be combined with targeted therapy depending on cancer aggressiveness.

What is HER2-positive breast cancer?

HER2 (also HER-2/neu or ErbB2) stands for human epidermal growth factor receptor 2 and is one of a family of several receptor proteins. Breast cancer cells that are HER2-positive have extra copies of the HER2 gene and produce extra HER2 receptor proteins.

Too much HER2 protein is thought to cause cancer cells to grow and divide more quickly. If a person is diagnosed with HER2-positive breast cancer, it means they are likely to have high levels of the HER2 protein on the outside of the cancer cells. This signifies that breast cancer has spread beyond the breast, which can be in the liver, bone, lungs or potentially even the brain.

Targeted therapy

• Targeted therapies find and attack fast-growing cells that have certain receptors, such as the HER2 receptor.
• Most targeted therapies are given with chemotherapy because the combination is more effective.

Common targeted therapies for HER2-positive breast cancer

Herceptin (trastuzumab)

• It is administered intravenously and usually with chemotherapy.
• It attaches to the HER2 proteins and blocks the signals that enable cells to multiply too quickly, causing cancer.
• Treatment with trastuzumab and chemotherapy reduces the risk of recurrence of cancer by half.
• Common side effects include fever or chills, muscle aches, nausea, skin reactions at the site of injection, a low white blood cell count and diarrhea. A rare but serious side effect is heart problems.

Perjeta (pertuzumab)

• It is used when the disease is at an early stage. It is given at the same time as trastuzumab and the chemotherapy medicine Taxotere (docetaxel).
• Like trastuzumab, pertuzumab works by blocking signals that enable breast cancer cells to multiply and grow.
• Pertuzumab is given by vein to breast cancer patients, who have a high risk of recurrence.
• It can be given for early-stage HER2-positive breast cancer either as neoadjuvant therapy (which means the medicine is started before breast surgery) or adjuvant therapy (which means it is given only after breast surgery).
• The patient may be able to take pertuzumab as neoadjuvant therapy in the following cases
  • If the cancer is larger than 2 centimeters across.
  • Locally advanced, which means it has spread to nearby tissue or lymph nodes.
  • If cancer is inflammatory (a type of breast cancer in the skin of the breast, where the breast looks red and swollen and feels warm to the touch).
  • Pertuzumab may be given with trastuzumab for up to one year of treatment, either starting with neoadjuvant therapy and continued after surgery or given entirely after surgery.
  • Common side effects include hair loss, diarrhea, nausea, rash, neuropathy and a low white blood cell count. Rare but serious side effects are heart and lung problems.

Tucatinib

This medication is given to patients in situations where the above drugs failed to cure cancer.

This drug can penetrate the brain and improve outcomes for patients with brain metastasis.

Breast cancer usually begins either in glands that make milk (called lobular carcinoma) or the ducts that carry it to the nipple (called ductal carcinoma). The cancer may grow and invade other areas around the breast, such as the skin or chest wall. Different types of breast cancer grow and spread at different rates.

There are several types of breast cancer and they are broken into two main categories: “invasive” and “noninvasive.” These two categories are used to describe the most common types of breast cancer, which include

• Ductal carcinoma in situ (DCIS): DCIS is a noninvasive condition. With DCIS, the cancer cells are confined to the ducts in the breast and haven’t invaded the surrounding breast tissue.
• Lobular carcinoma in situ (LCIS): LCIS is cancer that grows in the milk-producing glands of the breast. Like DCIS, the cancer cells don’t invade the surrounding tissue.
• Invasive ductal carcinoma (IDC): This is the most common type of breast cancer. This type of breast cancer begins in the breast’s milk ducts and then invades nearby tissue in the breast. Once breast cancer has spread to the tissue outside milk ducts, it can begin to spread to other nearby organs and tissues.
• Invasive lobular carcinoma: It first develops in the breast’s lobules and invades nearby tissues.

Apart from the above four types, below are a few more types of breast cancer.

• Paget disease of the nipple: This type of breast cancer begins in the ducts of the nipple, but as it grows, it begins to affect the skin of the nipple.
• Phyllodes tumor: This is a rare type of breast cancer that grows in the connective tissue of the breast. Most of these tumors are benign, but some are cancerous.
• Angiosarcoma: This cancer grows on the blood and lymph vessels in the breast.

With the recent approval of drugs as first-line treatment, the prognosis of HER2-positive breast cancer has  improved considerably. However, there is some concern about long-term cardiac toxicity as a side effect. In this new era of constantly rising health costs, it is also important to consider the cost-benefit ratio. Even if long-responding patients represent only a small group, it can be said that their numbers will grow in the future with the arrival of new drugs.