Pregnant With Breast Cancer: 5 Questions Women Need to Ask

As earth-shattering as a diagnosis of breast cancer can be, it's even worse for women who are pregnant at the time. A new study from the University of Texas M.D. Anderson Cancer Center, though, provides some reassuring news for those with what's commonly called pregnancy-associated breast cancer: It doesn't appear to be any more deadly—contrary to what was once thought—than breast cancer that occurs in women who aren't pregnant.

There are, however, many complicating factors that women still need to consider if they detect a breast lump while pregnant. (And young breast cancer patients who are not expecting a baby are advised to avoid pregnancy at least until after treatment.) Here are five important questions that women need to ask their doctors:

1. Mammogram or MRI? Small studies have shown that mammography poses little risk to the developing fetus if a lead shield is placed over a woman's belly to block any radiation scatter, according to breastcancer.org. Unfortunately, the X-ray isn't great at detecting tumors; researchers have shown that the test misses anywhere from 22 percent to 38 percent of malignancies in pregnant women compared with 15 percent of cancers in nonpregnant women. Ultrasound may be used before a mammogram to distinguish clear fluid-filled cysts (which are harmless) from solid lumps, but they can't differentiate the harmful solid lumps from the benign ones. Magnetic resonance imaging is more sensitive at finding breast tumors than mammography, but it's generally not performed during pregnancy because doctors worry about unknown health risks to the fetus posed by the test's strong magnetic fields.

2. How will s urgery and chemotherapy be timed? When possible, doctors prefer to delay treatment until a woman is past her first trimester, when all the fetal organs have developed. Unfortunately, risks to the baby from surgical anesthesia and chemotherapy can't be completely eliminated, and doctors usually discuss these risks in the context of helping women decide whether to continue with the pregnancy. Chemotherapy timing is particularly complicated because while it shouldn't be given during the first trimester, it also shouldn't be given within three to four weeks prior to delivery, according to the American Cancer Society. That's because it lowers a woman's blood count, raising her risk for bleeding and infections during childbirth.

3. Lumpectomy or mastectomy? Radiation treatments, which are routinely given after a lumpectomy, aren't safe for the baby at any stage in the womb, so women with early-stage tumors might want to opt for a mastectomy instead. Those who require radiation to prevent a local recurrence will have to delay these treatments until after childbirth.

4. When should't amoxifen start? Tamoxifen, which blocks estrogen, isn't given until after pregnancy because of studies indicating that it may be associated with certain birth defects.

5. Breast feeding, safe or not? If you're currently being treated for breast cancer, breastfeeding isn't considered safe. That goes for both chemotherapy and a hormone-blocking therapy like tamoxifen. For women who've finished all their treatment and who haven't had a double mastectomy, breastfeeding is still possible and often considered safe for both mom and baby.