The management of breast cancer during pregnancy

In this article, Dr Shiroma De Silva-Minor, highly experienced consultant breast oncologist, shares her expertise on the management of breast cancer during pregnancy.

Breast cancer is the most common malignancy affecting pregnant women, posing unique challenges in terms of diagnosis and treatment. Managing breast cancer during pregnancy requires a delicate balance between ensuring optimal maternal outcomes while safeguarding the health and wellbeing of the developing baby.

Although older data suggested worse breast cancer outcomes for patients, this is likely due to late diagnosis and under-treatment. All the indications now suggest that stage for stage, the outcomes for pregnant women with breast cancer are no different to non-pregnant women. There was also a previous tendency to advise women to terminate their pregnancy once a breast cancer was diagnosed, however termination does not improve cancer outcomes, and keeping the pregnancy should not prevent optimal breast cancer management (though it is slightly more complex, logistically).

Diagnostic challenges

Diagnosing breast cancer during pregnancy can be challenging due to physiological changes in the breast and limitations in imaging techniques. The increased vascularity and glandular tissue of pregnancy can obscure abnormalities on mammograms.

However, ultrasound scans are a safe and reliable way of detecting breast tumours. Fine-needle aspiration or core needle biopsy is the preferred method for obtaining tissue samples, as they carry a minimal risk to the foetus. X-rays and CT scans should be avoided at all stages during pregnancy.

Multidisciplinary approach

The management of breast cancer during pregnancy necessitates a multidisciplinary team involving breast surgeons, medical oncologists, radiation oncologists (or clinical oncologists like myself, who have expertise with both chemotherapy and radiotherapy), obstetricians, and paediatricians. This collaborative approach ensures comprehensive evaluation, optimal treatment planning, and appropriate counselling for both the patient and her family.

Treatment considerations

Surgery

Surgical options for breast cancer during pregnancy are similar to those for non-pregnant women and surgery can be undertaken at any stage of the pregnancy. Breast-conserving surgery or mastectomy can be considered and depends on a number of factors including the tumour size, tumour characteristics, patient preferences, and genetic mutations, among others. It may be preferable to have a mastectomy if the tumour is large or if radiation therapy is anticipated, but it would need to wait weeks or months until after delivery.

Systemic therapy

Certain chemotherapeutic drugs can be administered safely after the first trimester. The optimal timing may be after 17 weeks gestation, as prior to this there can be a significant impact on foetal cognitive development, which is significantly reduced by waiting 17 weeks, if clinically appropriate. Several chemotherapy agents are considered relatively safe for the foetus, but treatment should be individualised based on tumour characteristics and gestational age. Endocrine therapy is not recommended during pregnancy. Trastuzumab should be avoided in pregnancy and currently, there is no safety data for the use of immunotherapy, CDK 4/6 inhibitors or PARP inhibitors during pregnancy.

Radiation therapy

Ideally, radiation therapy should be deferred until after delivery to minimise potential harm to the foetus. However, in select situations, it may be considered during the second and third trimesters, taking into account foetal-shielding techniques and careful treatment planning.

Foetal monitoring

Regular foetal surveillance is crucial during the treatment of breast cancer in pregnancy. Close collaboration with obstetricians and paediatricians is essential to monitor foetal growth, development, and wellbeing, as they may be prone to be small for dates.

Timing of delivery

The optimal timing of delivery depends on various factors, including gestational age, tumour characteristics, and the need for further treatment. Whenever feasible, it is recommended to delay as close to term as possible. For patients receiving chemotherapy, delivery should be at least 2 weeks after the completion of systemic therapy to avoid maternal neutropenia at the time of delivery. If at any point, there are concerns about maternal or foetal wellbeing, an early delivery may be warranted.

Psychological and emotional support

A breast cancer diagnosis during pregnancy can be emotionally overwhelming for the patient and her family. Providing empathetic and supportive care is crucial throughout the treatment journey, with constant reassurance of anticipated excellent outcomes for both the mother and the baby. Engaging the patient with dedicated counsellors and support groups can help alleviate anxiety and facilitate coping mechanisms.

Although breast cancer is the commonest cancer in pregnancy, this is still a fairly rare event, and many breast oncologists will have little or no experience of managing this complex medical scenario. It is important to have treatment under an experienced specialist who is confident in the oncological management of breast cancer in pregnancy and the coordination of the multidisciplinary approach to ensure a successful outcome for both the mother and her child. As a member of the Advisory Board for Cancer in Pregnancy (ABCIP), I also advise clinicians on the optimal management of difficult cases of breast cancer in pregnancy, as part of the International Network of Cancer, Infertility and Pregnancy (INCIP).

If you would like to reach out to Dr Shiroma De Silva-Minor, head on over to her Top Doctors profile today.