Breast cancer during pregnancy can be treated without ending pregnancy

Bilge Türk | MediCenter TV

ISTANBUL, Türkiye — A breast cancer diagnosis during pregnancy does not automatically prevent treatment or require termination, as surgery and selected chemotherapy can often be planned while protecting both mother and fetus.

Pregnancy-associated breast cancer is diagnosed in approximately one out of every 3,000 pregnancies and is most frequently identified among women aged 32 to 38. Professor Yeliz Emine Ersoy of the Breast Center at Memorial Bahçelievler Hospital said cases could become more common as women increasingly have their first child at a later age.

The term pregnancy-associated breast cancer generally covers cancers diagnosed during pregnancy, within the first year after delivery or while breastfeeding. Treatment aims to protect the mother’s life while safeguarding the fetus and preserving the patient’s future fertility whenever medically possible.

Delayed diagnosis remains a major concern

Natural changes during pregnancy can make breast cancer more difficult to detect. The breasts may become larger, denser, tender or lumpy, while breastfeeding can produce further changes in breast tissue.

These changes can cause a newly detected lump to be mistaken for a normal feature of pregnancy, a blocked milk duct or another benign condition. Medical evaluation may therefore be delayed, allowing a suspicious lesion to remain undiagnosed for weeks or months.

Ersoy said the symptoms of breast cancer during pregnancy are not substantially different from those experienced by patients who are not pregnant. The most common sign is a persistent breast lump, which is often painless. Other possible signs include nipple discharge, skin dimpling, swelling, nipple changes or a persistent difference between the breasts.

Most breast changes detected during pregnancy or breastfeeding are not caused by cancer. However, a new lump or another unexplained change should be examined instead of being attributed automatically to pregnancy.

Ultrasound, mammography and biopsy remain possible

Breast ultrasound is usually the first imaging method used when a suspicious lump is detected during pregnancy. It does not use ionizing radiation and can help specialists assess the structure of a mass, examine nearby tissue and lymph nodes, and guide a biopsy when necessary.

Routine screening mammography is generally postponed during pregnancy, but diagnostic mammography may be performed when there is a clinical reason to investigate a suspicious finding. Mammography uses a small amount of radiation focused on the breasts, and medical teams can take appropriate precautions to keep fetal exposure as low as possible.

Because breast tissue becomes denser during pregnancy, mammography may not detect every cancer. Imaging results must therefore be assessed alongside the physical examination and the patient’s clinical history.

If a lump or imaging result remains suspicious, a tissue sample may be required for a definitive diagnosis. Pregnancy does not prevent a medically necessary breast biopsy. A core needle biopsy performed with local anesthesia is frequently used and generally presents little risk to the fetus.

The tissue obtained through biopsy also enables specialists to examine the tumor’s biological characteristics, including hormone receptor and HER2 status. These findings help determine which treatments may be effective and which therapies should be delayed until after delivery.

Treatment requires a multidisciplinary team

Breast cancer treatment during pregnancy must be individualized according to the cancer’s stage, the tumor’s biological characteristics, the week of pregnancy, the patient’s general health and her preferences.

Decisions should therefore be made by a multidisciplinary team rather than one physician alone. The team may include breast surgeons, medical oncologists, radiologists, pathologists, obstetricians, maternal-fetal medicine specialists and radiation oncologists. Psychological support and fertility counseling may also be included when appropriate.

Breast cancer surgery is generally considered possible during pregnancy when anesthesia, maternal health and fetal monitoring are carefully managed. Depending on the patient’s circumstances, doctors may consider breast-conserving surgery or mastectomy, which removes the entire breast.

The choice of operation depends on the size and location of the tumor, whether lymph nodes are involved, the stage of pregnancy and the additional treatments likely to be required. Not every patient begins treatment with surgery, as some tumors may require systemic treatment first.

Chemotherapy is avoided during the first trimester

The timing of chemotherapy is one of the most important considerations in treating breast cancer during pregnancy. Chemotherapy is avoided during the first trimester, when the fetus’s major organs are developing and exposure could cause serious harm.

For patients who need systemic treatment, certain chemotherapy regimens may be considered during the second and third trimesters. The choice of medication, dose and treatment schedule must be planned specifically for the individual patient.

The fetus should be monitored throughout treatment by an obstetric or maternal-fetal medicine team. Doctors may assess fetal growth and general well-being while coordinating cancer treatment with the expected delivery date.

Chemotherapy is generally not administered very close to delivery because it can lower blood cell counts and increase the risk of infection or bleeding for both mother and baby. The date of the final treatment cycle and the timing of delivery must therefore be coordinated carefully.

A breast cancer diagnosis alone does not mean that the baby must be delivered prematurely. When possible, the medical team aims to balance the urgency of cancer treatment with the benefits of allowing the pregnancy to continue safely.

Some therapies are postponed until after delivery

Breast cancer treatment can involve more than surgery and chemotherapy. Depending on the tumor, a patient may also require radiation therapy, hormone therapy, HER2-targeted medication, other targeted treatments or immunotherapy.

These treatments are not all considered safe during pregnancy. Radiation therapy, hormone treatments and HER2-targeted medicines are generally postponed until after delivery. Immunotherapy and several other targeted treatments are also not routinely administered during pregnancy because of potential fetal risks and limited safety evidence.

The medical team should prepare a plan for resuming or beginning these therapies after delivery. The decision may also affect whether the patient can breastfeed.

Some chemotherapy, hormone and targeted medicines can pass into breast milk or otherwise expose the baby to treatment. Breastfeeding may therefore be discouraged while certain therapies are being administered. The decision should be based on the specific drug and treatment schedule rather than a general rule.

Patients who hope to have more children should discuss fertility preservation as early as possible, ideally before systemic treatment begins. However, the methods available during an existing pregnancy may be limited, and not every option will be suitable for every patient.

Ending the pregnancy is not the standard approach

A breast cancer diagnosis does not automatically mean that a pregnancy must be terminated. Current evidence does not show that ending a pregnancy routinely improves cancer outcomes or overall survival.

The issue may still require individual discussion in cases involving metastatic disease, a highly aggressive tumor or treatment that cannot safely be postponed. Any decision should take account of the cancer’s characteristics, the week of pregnancy, the urgency of treatment and the patient’s informed preferences.

Many studies have found that survival outcomes can be similar for pregnant and nonpregnant patients when cancers are compared at the same stage. However, research findings are not identical for every patient group, so an individual prognosis should be based on the tumor’s stage and biological profile.

Experts emphasize that the central challenge is often delayed diagnosis rather than pregnancy itself. A persistent lump, unusual nipple discharge or a lasting change in the breast should not be ignored on the assumption that it is simply related to pregnancy or breastfeeding.

Modern treatment planning is built around three priorities: protecting the mother’s life, protecting the baby whenever possible and preserving future fertility when medical circumstances allow. Early evaluation and coordinated specialist care remain essential to achieving these goals.

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