Cancer in pregnancy is rare and so there aren't many studies on it. But breast cancer is one of the commonest cancers found in pregnant women. Many women are now delaying having children until their thirties and forties. And breast cancer risk increases as women get older.

Your daughter's treatment will depend on how far on she is in her pregnancy, the stage of her cancer and her own wishes. Ending the pregnancy (termination) doesn’t improve a woman's chances of recovery so doctors don't often advise this.

Surgery is usually the first treatment and is safe for the baby. If a woman has early breast cancer removing the lump (lumpectomy) is the usual treatment. Radiotherapy to the rest of the breast is then needed. But radiotherapy is usually avoided during pregnancy because of possible harm to the baby. Some women with early breast cancer need chemotherapy (which can be given in pregnancy). Radiotherapy is usually given after chemotherapy. So, the baby is born before radiotherapy starts.

Women who don't need chemotherapy sometimes decide to have their breast removed (mastectomy) rather than delay radiotherapy. Because, after mastectomy women are less likely to need radiotherapy. But if they're nearing the end of their pregnancy it may be safe enough to have a lumpectomy and delay radiotherapy until after the baby is born. Regardless of the pregnancy mastectomy may be the best treatment for some women.

Chemotherapy is usually avoided during the first three months of pregnancy because of the risks to the unborn baby. If a woman is only in the first few weeks of her pregnancy and she needs chemotherapy doctors may advise that she ends the pregnancy. If she's further along she may have to decide whether to delay her chemotherapy until she's past three months of her pregnancy.

After the first three months chemotherapy can be given. Chemotherapy at this time seems to carry little risk to the unborn baby. But if a woman is in the last three months of her pregnancy the baby can usually be delivered early providing the doctors believe it's safe to do so. Chemotherapy can then be given immediately after the baby is born.

Tamoxifen is not given during pregnancy. We don't know enough about its effects on the unborn baby. Herceptin a new treatment is also not usually given in pregnancy unless the benefits to the mother outweigh the risk to the baby. But there are reports of it having been given without causing harm to the baby.

Breast cancer during pregnancy can feel overwhelming. The diagnosis comes at a time which is usually joyful. Occasionally difficult decisions may need to be made about whether to continue with the pregnancy or not. Sometimes it's hard to balance the best treatment for the mother with the survival or safety of the unborn baby.

A woman with breast cancer in pregnancy is looked after jointly by a cancer specialist and an obstetrician (doctor who specialises in childbirth). The woman should always be fully involved in all discussions. She needs to understand her illness and how treatments may affect her and her pregnancy so that she can make her own informed decisions. Your daughter will need careful discussion with her doctors, partner and family. There is also specialist support available from nurses and counsellors.

References

• Chemotherapy for breast cancer during pregnancy: an 18-year experience from five London teaching hospitals. Journal of Clinical Oncology 2006
• Effect of adjuvant trastuzumab on pregnancy. Journal of Clinical Oncology (Jan 2006) 321-2
• Royal College of Obstetrics and Gynaecology. Evidence based guidelines on the management of breast cancer and pregnancy. Guideline No 12 revised 2004