Tamoxifen
Tamoxifen (Nolvadex) is a hormone therapy (also called endocrine therapy). It’s been used for over 40 years to treat hormone-receptor positive early, locally advanced and metastatic breast cancers. Tamoxifen is used to treat breast cancer in both women and men.
Learn about tamoxifen and treatment for ductal carcinoma in situ (DCIS).
Learn about tamoxifen and treatment for metastatic breast cancer.
How does tamoxifen work?
Hormone receptor-positive breast cancers need estrogen (a female hormone) to grow.
Tamoxifen attaches to the estrogen receptors in the cancer cell, blocking estrogen from attaching to the receptors. This slows or stops the growth of the tumor by preventing the cancer cells from getting the hormones they need to grow.
Tamoxifen and treatment for early and locally advanced breast cancers
Tamoxifen lowers the risk of [99]:
- Breast cancer recurrence (a return of breast cancer)
- Breast cancer in the opposite breast
- Death from breast cancer
Tamoxifen is a pill taken every day for 5-10 years. For premenopausal women, tamoxifen may be combined with ovarian suppression.
The benefits of tamoxifen may last 20 years after you stop taking it [108-110].
Talk with your health care provider if you have any questions or concerns about taking your medications.
Learn about the importance of completing treatment with tamoxifen.
| For a summary of research studies on tamoxifen for early breast cancer, visit the Breast Cancer Research Studies section. |
Taking tamoxifen for more than 5 years
Findings from a large randomized clinical trial showed taking tamoxifen for 10 years reduced the risk of breast cancer recurrence and death more than taking tamoxifen for 5 years [111].
These findings have led to increased use of tamoxifen for more than 5 years, especially among premenopausal women who can’t take aromatase inhibitors and women with breast cancers at higher risk of recurrence.
Taking tamoxifen for a longer time means a continued risk of health effects, such as endometrial cancer (cancer of the lining of the uterus) [111]. For premenopausal women, tamoxifen may also impact fertility.
Discuss the benefits and risks of taking tamoxifen for more than 5 years with your health care provider.
Learn more about tamoxifen and fertility.
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Susan G. Komen® Support Resources |
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Prescription drug assistance
Hormone therapy drug costs can quickly become a financial burden for you and your family.
Medicare and many insurance companies offer prescription drug plans. One may already be included in your policy, or you may be able to buy an extra plan for prescriptions.
Tamoxifen is a pill, so it’s covered under your health insurance plan’s prescription drug benefit rather than the plan’s medical benefit. This means there are usually out-of-pocket costs, which can add up over time.
You may qualify for programs that help with drug costs or offer low-cost or free prescriptions.
Generic drugs cost less than name brand drugs but are just as effective.
Many cancer centers have financial counselors who can discuss insurance and cost coverage with you.
Learn more about insurance plans and prescription drug assistance programs.
Learn about other financial assistance programs.
Komen Financial Assistance Program |
Susan G. Komen® created the Komen Financial Assistance Program to help those struggling with the costs of breast cancer treatment by providing financial assistance to eligible individuals. To learn more about this program and other helpful resources, call the Komen Patient Care Center at 1-877 GO KOMEN (1-877-465-6636) or email helpline@komen.org. Se habla español. |
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Susan G. Komen®‘s position on fairness in oral cancer drug coverage |
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Insurance coverage of oral cancer drugs Cancer medications given through an IV into a vein or by an injection (under the skin or into a muscle) are usually covered under a health insurance plan’s medical benefit. However, oral cancer drugs (cancer medications that are pills) are usually covered under a health insurance plan’s prescription drug benefit. As a result, people often find themselves facing high out-of-pocket costs when filling prescriptions for oral cancer drugs. Sometimes these costs can be thousands of dollars a month. The impact of high cost-sharing High prescription drug costs and the resulting out-of-pocket burden on patients are a barrier to care. They can prevent people from getting the medications prescribed by their health care providers. No one should be forced to get less appropriate treatment because an insurer gives more coverage for IV and injectable drugs than for pills. Efforts to increase fairness in drug coverage Komen supports state and federal efforts to require insurers to provide the same or better coverage for oral cancer drugs as they do for IV and injectable cancer drugs. This would help make sure patients have access to affordable, appropriate treatment. Become a Komen Advocacy Insider Sign up to be a Komen Advocacy Insider and get informed when action is needed on oral drug coverage parity at the state or national level. |
Updated 02/26/25
This content is regularly reviewed by an expert panel including researchers, practicing clinicians and patient advocates.
