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Biological and Targeted Therapy

Biological therapy is a treatment that uses substances normally produced by the body to treat cancer. A healthy and strong immune system can potentially detect the difference between healthy cells and cancer cells and destroy them. Biological therapy uses higher amounts of these substances made by the immune system to fight the cancer more effectively. Interferon is the most common form of biological therapy. There are several types of interferons that are manufactured. They interfere with the division of cancer cells and can slow their growth. Interleukins boost parts of the immune system to fight cancer.

Targeted (biologic response modifier) therapy affects specific characteristics of cancer cells, such as blood vessel growth or response to body substances. Monoclonal antibodies (MABs), such as trastuzumab, bevacizumab, or lapatinib modify the body's immune system to treat cancer. MAB's block specific receptors of substances that help the tumor grow.

These newer therapies have shown great promise, but pose some medical risks. Discuss them with your doctor.

Most biological therapies are given by injection into a vein in combination with chemotherapy or radiation therapy .

Side Effects

Possible side effects include:

  • Red, sore area where injection was given
  • Flu-like symptoms—fever, chills, gastrointestinal upset
  • Fatigue
  • Allergic reactions—cough, wheezing, skin rash
  • Confusion, disorientation, depression
  • Interleukin therapy is generally given in the hospital because it can cause severe changes in blood pressure
Special Considerations

These treatments can cause extreme fatigue. It is important to get as much rest as possible when your body is fighting cancer. Talk with your doctor about how best you can minimize side effects and the discomforts that come with treatment.

To date, vaccines and other immunotherapies have not been effective in killing breast cancer. There is always hope that this may be effective in some patients, and scientists feel that the greatest benefit from vaccinations against breast cancer may be in those patients who have a predisposition to developing the disease (most likely related to a family history or a genetic mutation in a gene such as BRCA-1 or BRCA-2).

Hormone Blocking Therapy

Hormonal therapy is designed to take advantage of the fact that many breast cancers are estrogen-sensitive. In other words, the hormone estrogen binds to the estrogen-sensitive cells and stimulates them to grow and divide. Anti-estrogen drugs, like tamoxifen, prevent the binding of estrogen. This stops the cells from growing and, in doing so, prevents or delays breast cancer recurrence.

Newer agents, like aromatase inhibitors, may be more effective than tamoxifen in both early and advanced stages of breast cancer. Examples of aromatase inhibitors include:

  • Anastrozole
  • Exemestane
  • Letrozole

In some cases, these agents are inappropriate, as in women who are premenopausal or who cannot tolerate aromatase inhibitors. Tamoxifen may be used instead of a newer agent. There is another type of hormonal therapy drugs called luteinizing hormone-releasing hormone (LHRH) agonists, which works by blocking how much estrogen the body makes. LHRH agonists may reduce the risk of cancer recurrence in premenopausal women who have early stage breast cancer. In some cases, it is used along with tamoxifen.

Side Effects

Hormonal therapy to treat breast cancer will cause menopause , including hot flashes, night sweats, change in mental status, and infertility . Managing these side effects may be difficult because hormone replacement therapy, which is used to manage menopause in healthy women, is not an option. It would counteract the effects of the anti-estrogen agents.

In addition to menopausal symptoms, other side effects can occur, such as:

  • Bone, muscle, and joint pain from aromatase inhibitors, tamoxifen, and LHRH agonists
  • Weakened bones from aromatase inhibitors and LHRH agonists
  • Blood clots, stroke , uterine cancer , or cataracts from tamoxifen
  • Fast or irregular heartbeat from LHRH agonists

Make sure to talk to your doctor about all medications you are taking. Some medications, when mixed, can cause problems. For example, when tamoxifen and certain antidepressants are taken together, this may increase the risk of death from breast cancer.


Breast cancer. American Cancer Society website. Available at: Accessed January 6, 2014.

Breast cancer in men. American Cancer Society website. Available at: Accessed January 6, 2014.

Breast cancer in men. EBSCO DynaMed website. Available at: Updated August 1, 2012. Accessed January 6, 2014.

Breast cancer in women. EBSCO DynaMed website. Available at: Updated January 3, 2014. Accessed January 6, 2014.

Goserelin. National Cancer Institute website. Available at: Accessed January 6, 2014.

Hackshaw A. Luteinizing hormone-releasing hormone (LHRH) agonists in the treatment of breast cancer. Expert Opinion on Pharmacotherapy. 2009;10:2633-2639.

Hormone therapy for breast cancer. National Cancer Institute website. Available at: Updated August 2, 2012. Accessed January 6, 2014.

Tamoxifen. EBSCO DynaMed website. Available at: Updated January 18, 2013. Accessed January 6, 2014.

11/16/2009 DynaMed's Systematic Literature Surveillance Goel S, Sharma R. et al. LHRH agonists for adjuvant therapy of early breast cancer in premenopausal women. Cochrane Database Syst Rev. 2009;(4):CD004562.

2/12/2010 DynaMed's Systematic Literature Surveillance Kelly CM, Juurlink DN, et al. Selective serotonin reuptake inhibitors and breast cancer mortality in women receiving tamoxifen: a population based cohort study. BMJ. 2010;340:c693.bmj.c693.

2/19/2010 DynaMed's Systematic Literature Surveillance Desmarais JE, Looper KJ. Interactions between tamoxifen and antidepressants via cytochrome P450 2D6. J Clin Psychiatry. 2009;70(12):1688-1697.

Last reviewed December 2014 by Mohei Abouzied, MD, FACP

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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