Letrozole
Letrozole is a hormone therapy and targeted therapy drug that blocks a protein called aromatase, which the body uses to make estrogen. Blocking aromatase lowers estrogen levels, which helps slow or stop the growth of breast cancer cells that need estrogen to grow.
FDA label information for this drug is available at DailyMed.
Use in Cancer
Letrozole is approved to be used alone or with other drugs to treat:
- breast cancer in postmenopausal women who have any of the following types of breast cancer:
- early-stage, hormone receptor–positive (HR+) breast cancer that has been treated
- early-stage breast cancer that has been treated with tamoxifen citrate for at least 5 years
- as the first treatment for breast cancer that is locally advanced or has metastasized (spread to other parts of the body) and is HR+
- as the first treatment for breast cancer that is locally advanced or has metastasized and it is not known whether the cancer is HR+ or hormone receptor negative (HR-)
- as the second treatment for breast cancer that has gotten worse after antiestrogen therapy
Letrozole is also available in a combination pack with ribociclib succinate. Ribociclib succinate and letrozole may work better together than when either is given alone. For more information that may apply to this combination pack, see the Drug Information Summary for Ribociclib Succinate and Letrozole.
Letrozole is also being studied in the treatment of other types of cancer.
More About Letrozole
Definition from the NCI Drug Dictionary - Detailed scientific definition and other names for this drug.
MedlinePlus Information on Letrozole - A lay language summary of important information about this drug that may include the following:
- warnings about this drug,
- what this drug is used for and how it is used,
- what you should tell your doctor before using this drug,
- what you should know about this drug before using it,
- other drugs that may interact with this drug, and
- possible side effects.
Drugs are often studied to find out if they can help treat or prevent conditions other than the ones they are approved for. This patient information sheet applies only to approved uses of the drug. However, much of the information may also apply to unapproved uses that are being studied.
Research Results and Related Resources
Targeted Therapy to Treat Cancers
Combo of Ribociclib, Letrozole Improves Survival in Advanced Breast Cancer
Hormone Therapy for Breast Cancer
Clinical Trials Accepting Patients
Find Clinical Trials for Letrozole - Check for trials from NCI's list of cancer clinical trials now accepting patients.