Treating cancer with hormone therapy

Hormone therapy is commonly used to treat breast and prostate cancers. Doctors consider several pieces of information to decide which hormone therapy, if any, is the best therapy for a patient.

Breast cancer treatment

• ER/PR testing: All breast cancers are tested for biomarkers called estrogen receptors (ER) and progesterone receptors (PR). Breast cancers with these biomarkers are called ER-positive and PR-positive or just hormone-positive. ER-positive and PR-positive breast cancers tend to respond to hormone therapy. 
• Recurrence scores: Special biomarker tests measure the risk for recurrence of ER-positive and PR-positive breast cancer. These tests can help to identify which patients may safely avoid chemotherapy and be treated with hormone therapy alone and for how long. OncotypeDX, Mammaprint and Prosigna are examples of these tests. 
• Stage of disease: Different hormone therapies are approved for different stages of breast cancer. Some are approved for use in combination with other medications or therapies, especially in people with advanced or metastatic breast cancer. 
• Prior treatment: If your breast cancer grows or recurs after hormone therapy, it is considered to be resistant to that therapy. Your doctor may switch you to a different hormone therapy agent or another type of treatment.  

Prostate cancer treatment

• If your prostate cancer appears to be contained within the prostate but is considered to be at high risk for spreading outside of the prostate, your treatment may include hormone therapy with surgery or radiation.
• Prior treatment: If your prostate cancer grows or recurs after surgery or radiation, your doctor may suggest hormone therapy or another type of treatment.  
• Hormone sensitivity: If your prostate cancer grows or recurs while receiving androgen deprivation therapy, your cancer is considered castration-resistant. If your cancer becomes castration-resistant, your doctor may recommend a different type of hormone therapy or another type of treatment. 
• Stage and grade of disease: Different hormone therapies are approved for different stages of prostate cancer. Some hormone therapies used in combination with other medications or therapies, especially in men with advanced or metastatic cancer. 

Timing of treatment

The goal of hormone therapy is to block the ability of hormones to cause growth and spread of cancer. Hormone therapy may be used during different phases of treatment: 

• Neoadjuvant hormone therapy is given to try to shrink a tumor before surgery. 
• Adjuvant hormone therapy is given to patients with early-stage disease after surgery to remove the tumor, when there is no longer evidence of disease. This is done to decrease risk of the cancer coming back.
• Hormone therapy may be used to treat people with advanced cancer to shrink tumors, reduce symptoms and decrease further spread of the cancer.