Hormone Therapy For Breast Cancer
Tamoxifen And Other Drugs



Hormone Therapy For Breast Cancer


What Is Hormonal Therapy?
When Is It Used?
Types of HT
Hormonal Medications
Which Drug Will I Be Prescribed?
How Long Do I Need To Take HT?
How Is HT Taken?
What Are The Side Effects?
Questions To Ask Your Doctor

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Breast Cancer Guide

What Is Hormonal Therapy?

As female hormones appear to play such a major role in causing breast cancer, one treatment strategy is to shift the body's hormone balance in order to discourage the growth of cancer. It is important to note at this point that hormonal therapy (HT) is not the same as hormone replacement therapy (HRT) or estrogen replacement therapy (ERT). HRT and ERT are used for treating symptoms of menopause such as hot flashes and menopausal depression. Neither HRT nor ERT are used as breast cancer treatments. Where HRT increases the amount of the estrogen in the body which tends to drop after menopause, HT does the opposite. It blocks or lowers estrogen levels in the body which is why it is considered an anti-estrogen therapy. In fact, for women with a breast cancer diagnosis, HRT is considered unsafe.

Historically, the first attempts at HT involved removing the ovaries from young women with virulent forms of breast cancer so that the ovaries could no longer produce estrogen to 'feed' the cancer cells. This type of surgery is used less often these days, although it is making some sort of comeback in Europe. The procedure is less invasive than it used to be and can now be carried out with a laparoscope. Studies show that the operation seems to show similar results to those women who undergo chemo instead. The main issue however is that it causes premature menopause and the woman enters menopause overnight (read about the effects of menopause on the body). Today in the U.S., HT is more commonly performed with the use of drugs, in particular tamoxifen (Nolvadex).

When Is It Used?

HT, like chemotherapy, is a systemic treatment. That means it treats the whole body, and not just one specific area (like radiation therapy). Systemic therapies are normally recommended where the oncologist suspects that cancer cells have escaped the breast area. HT may be a recommended form of treatment after a lumpectomy or mastectomy - particularly if a breast biopsy of the tissue removed shows cancer at the margins and the cancer is estrogen receptor positive (see below). HT also helps to:
1. Prevent cancer returning to the same area after a tumor has been removed.
2. Decrease the likelihood of cancer appearing in the other breast.
3. Slow or stop the growth of cancer which may have spread to other parts of the body.
4. Reduce the size of a tumor before surgery.
5. Reduce the chance of the disease developing in women with high risk factors for breast cancer. This includes women with a strong family history of the disease and who may have tested positive for BRCA gene mutations.

Types of HT

HT is used to treat what is known as hormone receptor positive breast cancers. These receptors are like little ears on a breast cell which listen for signals and instructions from hormones - such as when to grow or multiply.

• 80 percent of breast cancers are estrogen receptor positive.
• 65 percent are estrogen and progesterone receptor positive.
• 13 percent are estrogen receptor positive and progesterone receptor negative.
• 2 percent are estrogen receptor negative and progesterone receptor positive.

If a cancer is either estrogen or progesterone receptor positive, it is considered hormone-receptor-positive. If it has neither receptor it is considered negative and HT as a treatment cannot help. Additionally as HT affects the action of estrogen only, the value of the treatment is less clear to patients who are progesterone receptor positive and estrogen receptor negative. These 2 percent of cases will need to discuss the pros and cons of therapy with their oncologist.

Hormonal Medications

There are 3 different types of HT medications. These are: Selective Estrogen Receptor Modulators (SERMs), Aromatase Inhibitors and Estrogen Receptor Downregulators (ERDs).

Like all hormone manipulations, these drugs do not kill cancer cells, instead they stop them growing and spreading. There are are 3 main drugs in this group: tamoxifen (brand name nolvadex), raloxifene (evista) and toremifene (Fareston). Tamoxifen is the oldest and most popular of these drugs used in the United States. Initially researchers thought it worked by starving the cancer cells of estrogen so that they stopped growing. Now it appears that the mechanism is more complex. It may be that the drug fools the cancer cell into accepting the imposter (the SERM) as the real hormone, or it may act in some other way that we have yet to discover. Taking 1 tamoxifen pill a day seems to give postmenopause women a better breast cancer survival rate.

Aromatase Inhibitors
Also estrogen blockers, these drugs work by blocking the enzyme aromatase which turns the hormone androgen into estrogen. They cannot stop the ovaries from producing estrogen so they are only effective in postmenopausal women. Brand names include Aromasin, Arimidex and Femara. They appear to be particularly effective against early cancer and may eventually become an alternative to SERMs.

Estrogen receptor downregulators work in a similar way to SERMs by blocking the effects of estrogen. The ERD sits in the estrogen receptor of the breast cells, so that when estrogen comes along there is no room for it to attach to the cell. To date there is only one ERD approved by the FDA and that is Faslodex (generic name fulvestrant).

Which Drug Will I Be Prescribed?

This depends on a number of factors:

1. Your stage of breast cancer.
2. If you have a history of blood clots.
3. Your status in regards to menopause (premenopausal, perimenopause or postmenopausal).
4. Your bone density.
5. Any personal history of arthritis.
6. If you have a higher than average risk factor for cancer of the ovaries or uterus cancer.

Early Stage Cancer After Menopause
The American Society of Clinical Oncologists (ASCO) recommends women with hormone receptor positive breast cancer in this category to use an aromatase inhibitor. If the woman has been taking tamoxifen for 2 or 3 years they may be advised to switch to an aromatase inhibitor. After 5 years of tamoxifen, women may also be recommended aromatase inhibitors to further reduce the risk of breast cancer recurrence.

Early Stage Cancer Before Menopause
Tamoxifen is usually recommended in this case if cancer is receptor positive.

Advanced Cancer
Tamoxifen is usually recommended for 2 to 5 years in women with advanced receptor positive breast cancer. If the drug stops working - or after 2 to 5 years of tamoxifen - some patients may switch to an aromatase inhibitor. If tamoxifen and aromatase inhibitors stop working, then Faslodex may be tried.

How Long Do I Need To Take HT?

This depends on whether or not you are taking it before or after cancer surgery, the stage of your cancer and the side effects it causes. Postmenopause women who take HT after surgery usually do so for 5 years. Sometimes a different medication may extend this timeframe. For example, sometimes doctors recommend an aromatase inhibitor for another 5 years after 5 years of tamoxifen. Postmenopause women taking HT before surgery may need to take it for 3 to 6 months, just to shrink the tumor. This is known as neoadjuvant hormonal therapy. Women of all ages with advanced receptor positive breast cancer usually keep taking HT indefinitely as long it keeps working. This may require switching medications every so often.

How Is HT Taken?

All the HT treatments, except Faslodex, are taken as a pill once a day. Faslodex is a liquid which needs to be injected by a doctor once a month.

What Are The Side Effects?

SERMs Side Effects
SERMs like tamoxifen can cause some serious medical complications such as stroke in women, endometrial cancer and blood clots. Signs to look out for include:

Abnormal vaginal bleeding or discharges
Pressure or pain of the pelvis
Chest pain in women
Swollen legs
Shortness of breath
Tingling or weakness of the face, arms or legs
Sudden vision problems
Severe headaches
Other common problems include:
Hot flashes and night sweats
Vaginal discharge
Mood swings

Aromatase Inhibitors Side Effects
Osteoporosis in women and bone fractures. This is why some doctors will carry out a bone density test before prescribing aromatase inhibitors. They may also instruct the patient to take bone strengthening medications to prevent osteoporosis. Other common side effects include joint pain and stiffness. You may want to check out books on breast cancer and survivor stories before starting any therapy. Knowledge is power.

ERDs Side Effects
Hot flashes
Nausea and vomiting
Stomach pain
Sore throat

Questions To Ask Your Doctor

Women Just Diagnosed With Receptor Positive Breast Cancer

1.Which HT do you recommend for me and why?
2. Can you compare the side effects and benefits of aromatase inhibitors and tamoxifen?
3. How many years will I need to take HT?
4. Do I need to take any menopause tests to determine if I am pre or post menopause?
5. Do I need to take a bone density test?

Women Who Have Been Taking Tamoxifen For 2 or 3 Years

1. Do you think I should switch to an aromatase inhibitor? If not, why not?
2. How much longer will I need to take tamoxifen if I don't switch?
3. How long would I have to take aromatase inhibitors if I do switch?
4. What side effects will switching cause?

Women Who Have Taken 5 Years Of Any HT Drug

1. Is there any reason for me to continue with HT?
2. Is there any reason for me to stop taking my current HT medication and switch to another type?
3. If I do switch, how many years will I need to continue taking the next medication?

Related Articles on Cancers

For more information, see the following:

Cancer guide: Treatment, causes and clinical trials.
Inflammatory breast cancer: Spot the early signs.
Breast reconstruction surgery: How it is performed.

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