Breast Cancer Drugs

Dashed Hopes

If you have PCOS and have been trying to conceive (TTC), you know that this is one of the hardest tasks you've ever been called on to achieve. In general, the husband is checked for any problems with his sperm, and once that's ruled out, the physician's next stop is putting you on a trial of Clomid for 4-6 cycles. That's 4-6 months of hopes dashed, over and over again.

At that point, perhaps your doctor will decide to increase the dosage, maybe add in a dash of IUI, and if that doesn't work, will try you on some of the injectable medications. By this time, you're wondering if there's anything left for you to try. Then you get to talking with a friend who had similar woes, but who tried Tamoxifen or Femara and found themselves first ovulating, and then conceiving. You may be ready to try just about anything in your quest to have a baby, but this sounds very strange: aren't those supposed to be breast cancer treatments?

The quick answer is that you're right. Both Tamoxifen and Femara (letrozole), were created to treat or prevent the type of breast cancer that responds to hormones. Tamoxifen works as an antiestrogen and interferes with the body's estrogen receptors. This makes your body think your estrogen levels are lower than they really are.

Femara acts in a more direct manner and keeps your body from producing the enzyme known as aromatase. It is aromatase that is the responsible agent in your body for the production of estrogen. Through this aromatase inhibition, Femara manages to block estrogen production. Because of their effect on estrogen levels, both Femara and Tamoxifen can increase fertility and ovulation rates.


Clomid does its magic on your pituitary glands, but the two cancer drugs go straight in to the ovaries. There are doctors who feel that this more direct course is the reason that the drugs provide improved follicular development. There are also doctors who feel that women with polycystic ovarian syndrome (PCOS) do better with Tamoxifen than with Clomid.

On the other hand, if you are using Tamoxifen or Femara because of breast cancer or to prevent breast cancer you will want to take contraceptive measures since the drugs can cause birth defects should you become pregnant during treatment. Treatment in this case tends to be given over a five year period, so these are five years when pregnancy is out of the question.

The thing is that these drugs stimulate the ovaries, but damage embryos. However, most drugs prescribed for infertility are bad news for early pregnancies. This is why doctors always monitor your status as you undergo the various treatments.

A doctor will sometimes agree to let you suspend breast cancer prevention or treatment with these drugs for a two year period so you can have a baby. But you shouldn't assume that you can get away with such a course of action without receiving the blessing of your oncologist.

One of the benefits of Tamoxifen and Femara is that they clear out of your body just as soon as you've taken your last dose. That means that the likelihood of harming an early embryo is very slight. Another good thing: some doctors swear they're seeing more babies with Femara than with Clomid treatment and feel it has fewer side effects.

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