Fertility After Chemotherapy

Many women want to know if they'll be fertile after chemotherapy. Fertility after chemotherapy depends on two things: your age and the types and doses of chemotherapy medicines you get.

Your age: As every woman ages, her ovaries produce fewer fertile eggs. When you go into menopause, your ovaries stop making fertile eggs.

• Women who are treated for cancer younger than age 30 have the best chance of becoming pregnant after chemotherapy. Overall, the younger you are, the more likely it is your ovaries will produce fertile eggs after chemotherapy.
• The closer you are to menopause (the average age is 51), the more likely it is that you'll be in menopause after chemotherapy and won't be able to become pregnant.
• Women who are 40 or older when they get chemotherapy are more likely to be in menopause after chemotherapy.

The types and doses of chemotherapy drugs you get: We know that certain chemotherapy medicines are more likely than others to cause infertility, including Cytoxan (chemical name: cyclophosphamide). Platinol (chemical name: cisplatin) and Adriamycin (chemical name: doxorubicin) carry a medium risk of losing fertility.

On the other hand, certain chemotherapy medicines are less likely to cause infertility:

• methotrexate (brand names: Mexate, Folex, Rheumatrex)
• fluorouracil (also called 5-fluorouracil) (brand name: Adrucil)
• vincristine (brand names: Oncovin, Vincasar PES, Vincrex)

The taxanes:

• Taxol (chemical name: paclitaxel)
• Taxotere (chemical name: docetaxel)
• Abraxane (chemical name: albumin-bound or nab-paclitaxel)

are a relatively new group of chemotherapy medicines. Few studies have been done on how these medicines may affect fertility and the results aren't clear yet.

Because research in this area is limited, it can be difficult to give an individual woman an accurate idea of her chances of keeping her fertility. It's a good idea to talk to your doctor, a fertility expert, or both about the potential risk of infertility with your chemotherapy treatment plan.

Here's what we do know:

• Early menopause brought on by chemotherapy may be temporary. In other words, your menstrual periods may stop and then start again after chemotherapy is over. It can take a few months or as long as a year or more for your periods to return.
• Periods don't always mean fertility. Even if your periods start after treatment, your fertility may be uncertain. You may need to see a fertility expert to help you find out if you're actually fertile.
• Women who get relatively high overall doses of chemotherapy may be more likely to be infertile after treatment than women on lower-dose regimens.
• Chemotherapy medicines are usually given in combination, not each one by itself. When used in combination, the medicines' effect on fertility may be different. It's also important to know that the same medicine may be given in different doses in different combinations.
• Some women who have normal periods after chemotherapy may be able to get pregnant with no difficulty while others may have trouble getting pregnant. This is because chemotherapy can damage the immature eggs in the ovaries.
• When your periods return after chemotherapy, it means that some eggs are maturing. But the number of eggs available may be smaller than it was before chemotherapy.
• Because chemotherapy may cause birth defects, doctors advise using birth control -- but not birth control pills -- throughout chemotherapy so you don't become pregnant during treatment.
• It's important to wait at least 6 months (or longer) to get pregnant after chemotherapy ends. You don't want to get pregnant with an egg that was damaged by chemotherapy.
• After chemotherapy, fertility may be short-lived. This means that even women whose periods start again after chemotherapy are at some risk of early menopause.

Researchers are looking at ovarian suppression -- stopping ovarian function using medicine -- to help protect a woman's eggs during chemotherapy. But this is very controversial because there is limited information available.

Some doctors are concerned that the medicines used to suppress ovarian function, called GnRH (gonadotropin-releasing hormone) agonists, may interfere with chemotherapy's ability to kill cancer cells when the cells are actively growing. GnRH agonists are hormones, and besides suppressing ovarian function, they may also stop or slow the growth of breast cancer cells. This would make the cancer cells less sensitive the chemotherapy.

The GnRH agonists used in ovarian suppression include:

• Zoladex (chemical name: goserelin)
• Lupron (chemical name: leuprolide)
• Trelstar (chemical name: triptorelin)

These medicines block GnRH, a special hormone made in the brain that tells the ovaries to get ready for ovulation. Ovulation happens when a mature egg is released from the ovary, ready to be fertilized. When GnRH is blocked, no ovulation occurs.

Right now, one study suggests that premenopausal women diagnosed with hormone-receptor-negative, early-stage breast cancer who were treated with Zoladex while they were getting chemotherapy before breast cancer surgery were much less likely to be infertile after chemotherapy ended. It’s important to know that this study applies only to women diagnosed with hormone-receptor-negative disease.

Expert Quote

"In general, all women with breast cancer who are in their reproductive years should be counseled regarding fertility preservation. Chemotherapy affects fertility in every woman, regardless of age."

-- Kutluk Oktay, M.D.

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