Systemic Therapy

Systemic therapies are drugs that spread throughout the body to treat cancer cells wherever they may be. They include chemotherapy, hormonal therapy, targeted drugs, and immunotherapy. Memorial Sloan Kettering is a leading center for the development of innovative systemic therapies for breast cancer. Our healthcare team has extensive experience in using these therapies to treat patients. They can also help you to anticipate and manage the side effects of your treatment.

After surgery, many women benefit from adjuvant (additional) systemic therapy. The goal of this treatment is to reduce the risk of breast cancer recurring (coming back) or metastasizing (spreading). Sometimes we give this treatment before surgery — an approach called neoadjuvant therapy — to help shrink the tumor and make it easier to remove surgically. In both of these situations, the main aim is to kill or control unseen microscopic metastases before they grow. This reduces the risk of distant spread of breast cancer in the years after surgery.

Whether you would benefit from adjuvant systemic therapy and which type best suits your condition depends on such factors as:

  • the presence or absence of cancer cells in your lymph nodes
  • the size of your tumor
  • your menopausal status
  • whether your tumor contains hormone receptors or overproduces certain proteins, such as HER2/neu
  • whether you have a high recurrence score on OncotypeDx® testing, which analyzes the activity of a group of genes that can influence how cancer might behave or respond to different treatments

We may also recommend that you take part in a clinical trial of an investigational new treatment.

Treatment of Metastatic Disease

Women with metastatic breast cancer may receive various systemic therapies to control the disease. These include chemotherapy, hormonal therapy, biologics, immunotherapies, other targeted agents, or combinations of these. The choice of treatments depends on certain characteristics of the tumor, such as hormone receptors, HER2/neu status, and the location of the disease.    

There are a large number of chemotherapy drugs that work in many different ways. In a very general sense, these drugs can help you fight breast cancer by interrupting the growth and spread of cancer cells. Each of them works in a somewhat different fashion and their dose, schedule, and use, either alone or in combinations, can lead to different levels of effectiveness.

Hormone Therapy
Since some breast cancers rely on estrogen and other hormones to fuel their growth, medicines that block or stop this can potentially keep these tumors from growing.

Targeted Therapy
A current focus of breast cancer research is to find drugs that work by targeting specific molecules involved in breast cancer development, growth, and spread. Early success in this area includes several drugs that target HER2, but there are a growing number of agents and targets that show promise. Many of them are only available within formal clinical trials, though an increasing number have been approved for routine use. The optimal timing and use of these drugs is still being studied.