Breast cancers can occur during pregnancy or in the early post partum period when women are breastfeeding. This is obviously a very difficult time particularly in the diagnosis of the breast cancer as there are significant changes in the breasts during pregnancy and lactation.
In terms of diagnostic tests, it is safe to undergo breast ultrasound and biopsy during pregnancy. Mammography can be performed; however, special precautions are required in terms of shielding of the abdomen. An MRI is not safe during pregnancy or breastfeeding.
Surgery can be undertaken in any stage during pregnancy but it is usually delayed until the end of the 1st trimester and surgical options for breast cancer are the same; however, consideration needs to be given as to whether or not radiotherapy will be required.
Radiotherapy is not recommended during pregnancy and will usually be delivered after the baby is born. It should be given soon after chemotherapy and therefore, if a patient is in the early stages of 1st trimester of their pregnancy, a mastectomy may be recommend by the doctor rather than breast conservation as radiotherapy is often not required post mastectomy.
The use of sentinel node biopsy during pregnancy is thought to be safe as only small doses of radioactive isotope injection are required.
The treatment for breast cancer during pregnancy will depend on which stage of the pregnancy the breast cancer is diagnosed. Certainly, in the 1st trimester, a termination would be advisable. However, in the 2nd and 3rd trimester, chemotherapy may be given. The risk of miscarriage or birth defect associated with chemotherapy in the 2nd and 3rd trimester is extremely low. The chemotherapy drugs used in pregnancy are safe as they do not cross the placenta from the mother’s blood to the unborn baby. However, chemotherapy is best avoided in the 1st trimester.
Hormonal therapy/endocrine treatments are often given after surgery, chemotherapy, and radiotherapy and they should be delayed until the baby is delivered. It is important for all women to understand all of their options carefully. The diagnosis of breast cancer is not a surgical emergency. It is, however, a psychological emergency, although it is extremely important particularly in the diagnosis of breast cancer in young women that all of the treatment options are discussed and patients are given opportunity to decide on the right treatment decision for their individual situation.