Pregnancy and breast cancer

Breast cancer is the most common cancer in women. Although it is more common in older women, 1 in 7 cases are found in women aged under 45. Treatment success rates are good in the UK and are improving all the time. Increasing numbers of young women who have been treated for breast cancer are now going on to have babies.

Getting breast cancer during pregnancy only happens rarely, and being pregnant does not appear to affect how successful treatment is.

There are natural changes in your breast when you are pregnant or breastfeeding. However, if you notice a lump, it is important that you see your GP or obstetrician, who will refer you to a specialist breast team if needed. The team will offer you an ultrasound scan of your breast. Ultrasound is safe in pregnancy.

Sometimes a special X-ray of your breast (mammogram) is needed. In this situation, your abdomen will be shielded to prevent the X-rays affecting your baby.

A small sample (biopsy) of your lump will usually be taken. You will be given a local anaesthetic to numb the area. Your medical team will be able to tell from the results whether cancer is present. It is important to remember that most breast lumps are non-cancerous (benign).

The treatment you will be offered will depend on the type and extent of your breast cancer, the stage of your pregnancy and your individual circumstances. You will be able to talk about the various treatments available to you with your breast team. You will be given a key worker, often the breast specialist nurse, who will coordinate your care and keep in touch with you.

The three treatment options available to you are surgery, radiotherapy and drug treatment. Your breast team will discuss with you the best treatment in your situation.

Surgery

Surgery can be carried out at any stage in pregnancy. There are two forms:

• the most common is removal of the lump (lumpectomy); some of the lymph nodes in your axilla (armpit) may also be removed
• removal of the breast (mastectomy).

Your breast surgeon will discuss both options with you, so that you can make the best decision for you.

If a reconstructive operation is appropriate for you, it will not be done until after your baby is born. This is to give time for the hormonal changes in your breasts to settle down after pregnancy.

Radiotherapy

If required, radiotherapy is usually delayed until after your baby is born.

Drug treatment

Chemotherapy is not usually given during the first 13 weeks of pregnancy because it might cause abnormalities in your baby. After that, it is safe and you may be offered chemotherapy depending on your type of breast cancer. The anti-sickness and steroid treatments that you may need to control the side effects are safe for pregnant women to take. They will not harm your baby.

Two commonly used drugs, tamoxifen and trastuzumab (Herceptin), are often given after the initial treatment to reduce the chance of the cancer recurring. However, it is not recommended to take these drugs in pregnancy and treatment with these drugs will be delayed until after your baby is born.

Most women choose to continue their pregnancy while they receive their treatment for breast cancer.

However, if the cancer is advanced when it is found or is diagnosed in the first 3 months of pregnancy, the team looking after you will discuss the option of ending the pregnancy to allow your treatment to start earlier. These are difficult choices to make and you will be given the support to make the best choice for you and your family.

A specialist team including a consultant obstetrician, midwife and the breast team will look after you throughout your pregnancy. Your GP will be kept informed.

Most women who have been treated for breast cancer during pregnancy will carry their babies to full term and can expect a normal birth. If your baby is likely to be born early (premature birth) you will be offered a course of corticosteroid injections, usually over a 24–48 hour period, to help with your baby’s development and reduce the chance of breathing problems caused by being born early. You can find out more about this from the RCOG patient information Corticosteroids in pregnancy to reduce complications from being born prematurely: information for you.

If you are having chemotherapy, the treatment will normally stop 2–3 weeks before a planned birth of your baby to allow your body to recover.

If you have had surgery or radiotherapy, you may not produce milk in that breast but the other breast will not be affected. If you wish to breastfeed, the midwives will encourage and support you. Breastfeeding will not increase the risk of your cancer coming back. It is perfectly safe to breastfeed if you have had chemotherapy in the past. However, you should not breastfeed if you are still receiving chemotherapy, tamoxifen or Herceptin.

It is important to use reliable contraception during breast cancer treatment. You may be advised not to use hormonal contraception such as the pill or contraceptive implants. Non-hormonal contraceptives such as the coil (intrauterine contraceptive devices) may be a good choice for you. Talk to your breast team about the best contraception for you.

Your plans for future pregnancies should be taken into account when your medical team discusses the best treatment with you.

Wherever possible, your breast cancer specialist will choose chemotherapy drugs that are less likely to affect your fertility. Some drugs can affect your ovaries, which may reduce your chance of having a baby. As with all women, future fertility will also depend on your age. Other drugs (for example, tamoxifen and Herceptin) do not appear to affect fertility, but you should avoid becoming pregnant while taking them. Wait until the treatment has finished.

It may be possible in some cases to freeze your eggs or embryos before chemotherapy begins. You should be given written information about your options and have the opportunity to talk about your plans with the team, who can refer you to a fertility specialist.

You can find out more information at Breast Cancer Care: https://breastcancernow.org/information-support/publication/fertility-pregnancy-breast-cancer-bcc28.

Speak to your breast team before becoming pregnant. You will usually be advised to wait for at least 2 years after your treatment has finished before trying for a baby as it is during this time when breast cancer is most likely to come back. Talk to your breast team if you think you may want to be pregnant sooner.

If you are taking tamoxifen, discuss with your breast team when to stop taking it. Normally this would be 3 months before trying for a baby. Don’t stop any treatment without first discussing it with the team looking after you.

If you have received certain chemotherapy drugs before you were pregnant, you should be offered a detailed scan of your heart (echocardiography). This is because there is a small risk of you developing heart problems during pregnancy with these drugs.

The rates of miscarriage, stillbirth or your baby having a birth defect appear to be the same as for anyone else. Pregnancy will not increase the chance of the cancer coming back.