Hormone Therapy for Metastatic Breast Cancer: Faslodex FAQs

Patient Expert

Q. I'm devastated" I've had a recurrence, and it's not just local-it's metastatic. One of the things my oncologist said I have to do is take Faslodex. Can you tell me something about it?

A. Faslodex (fulvestrant) is the next step after tamoxifen for some of us. It's for postmenopausal women with ER/PR-receptive breast cancer that hasn't responded to an anti-estrogen drug (primarily tamoxifen), or that has stopped responding to that kind of drug.

Faslodex does three different things to stop the growth of cancer. First, it mimics tamoxifen by blocking estrogen from attaching itself to the special receptors on cancer cells. Think of making blueberry muffins. You fill each muffin cup with batter, and any leftover batter you have at the end-too bad, nowhere to go. Faslodex "fills" a cell's estrogen receptors, leaving no room for estrogen. Breast cancer cells deprived of their estrogen go dormant, and almost always eventually die; some even die immediately.

In addition, Faslodex changes the shape of the estrogen receptors themselves, causing them to become less functional; and the cancer cells of patients treated with Faslodex actually show a decrease in estrogen receptors over time. So it's a triple threat, and is called a "second line defense" against metastatic cancer, once tamoxifen et. al. have failed to be effective.

The very latest research, a Phase III clinical trial whose results were published in March, 2008, details the effects of taking Faslodex after you've taken Aromasin, an aromatase inhibitor. (More and more postmenopausal women are skipping tamoxifen altogether, and going directly to an AI after their active treatment.) The study notes that ongoing trials are studying high-dose Faslodex, or Faslodex in combination with an AI, which might be more effective than the current standard of treatment using Faslodex. Ask your oncologist if he has any information on the subject.

Q. How do I take Faslodex? Is it a pill like tamoxifen, or what?
A. Faslodex is given, once a month, as a 250mg injection (or two 125mg injections), intramuscularly, into one of the most padded spots on your body: your bottom. It's quite a large injection, and is given slowly, so it takes longer than a typical split-second shot in the arm. Nevertheless, women report that it's generally not very painful; perhaps just a bit sore around the injection site for a little while.

Unlike chemo; or tamoxifen, or most other hormone therapies, there's no set duration for taking Faslodex. You'll take it till it works to put your cancer in remission, or until your oncologist decides to try something else.
One positive about having an injection rather than taking a pill: it's given in your doctor's office, meaning it's covered by insurance as a procedure, rather than being considered a medication. For those of you with health insurance but without a good prescription plan, this is a real plus.

Q. And how about side effects?

A. The most common side effects from Faslodex include the following:

  • Gastrointestinal problems, including nausea, vomiting, constipation, diarrhea, and abdominal pain;
  • back pain;
  • headache;
  • hot flashes;
  • sore throat.

Luckily, many of the same anti-nausea drugs given for chemo are effective against Faslodex's side effects. So don't suffer in silence, or figure "this is the price I have to pay." As a doctor friend of mine says, "A stiff upper lip isn't the cure for anything." Whatever side effects you encounter-and there's no telling which, if any, will affect you-tell your oncologist or onco nurse. They probably have something to counter whatever discomfort you're experiencing. Good luck