Pregnancy-Associated Breast Cancer

Breast cancer during pregnancy

Pregnancy-associated breast cancer (PABC) is relatively rare. PABC is defined as breast cancer occurring during pregnancy, first postpartum year, or anytime during lactation. It is estimated to occur in 1 every 3000 pregnancies. On the other hand, it is the most common cancer during pregnancy, the incidence of PABC is expected to rise in developed countries, while historically PABC was always thought to have poor prognosis this is not universally true, it continues to represent a special challenge for early diagnosis and treatment options.

Prognosis, it is now generally accepted that prognosis of patients with PABC matches to that of non-pregnant of the same age and clinical stage, there is no scientific evidence to suggest that termination of pregnancy improves prognosis, also, future pregnancy should be discussed with physicians and not to be discouraged. The following must also be noted.

  • Normal breast physiologic changes may cause a delay in diagnosis.
  • Histology is often poorly differentiated with lymphovascular invasion.
  • PABC occurring during lactation is of worse prognosis, compared with non-pregnant BC, patients diagnosed with breast cancer within one yer of delivery have the worst prognosis, with increased risk of metastases and death.

Diagnosis, pregnant patients presenting with breast mass is approached in a similar fashion to non-pregnant patients but with some limitations, ultrasound is safe and can be complemented with mammography which is generally considered safe, however, it is less sensitive for diagnosis PABC. Ultrasound core needle biopsy with breast cancer profile including hormone receptors status and HER2 is the gold standard. Breast MRI is of controversial value due to common breast physiologic changes and high false positivity. Chest X-ray with shielding, liver ultrasound should complete the staging workup. Bone scan to be avoided.

it is important to have a high index of suspicion to diagnose PABC in a timley fashion.

Treatment, This must be done in true multidisciplinary with a coordinated team including the surgeon, medical oncologist, radiation oncologist as well as obstetrician (preferably a specialist in maternal and fetal medicine). In general treatment of PABC follow the same guidelines for non-pregnant breast cancer, however, there are some necessary modifications to protect the fetus, please see the summary of treatment table below. Treatment must start during pregnancy as delaying treatment was shown to worsen prognosis.

Surgery, breast surgery (mastectomy or breast conserving surgery) and axillary surgery are generally regarded as safe during all trimesters. Mastectomy should be considered to for patient at an early stage such as stage I and stage II, mastectomy has the advantage of obviating the need for adjuvant radiation therapy, this is become and feasible options for a patient diagnosed in early pregnancy since radiation can not be done until after delivery. Breast conserving therapy can also be used during pregnancy, however, to achieve therapeutic equivalence with mastectomy the patient must receive radiation therapy which must wait for the completion of pregnancy making breast conserving surgery less feasible for patients diagnosed in early pregnancy. Axillary management is a very important aspect of the surgical care of PABC, the use of sentinel lymph node biopsy is controversial, and use of blue dye is contraindicated. Axillary lymph node dissection is the standard.

Chemotherapy, This should follow the same guidelines as non-pregnant breast cancer, with special attention to the timing of treatment, chemotherapy is contraindicated during the first trimester. It is generally regarded safe during the second and third trimester (but to be avoided beyond the 35th week), it is also associated with risks including preterm delivery, low birth weight, transient tachypnoea of the newborn, and transient neonatal leukopenia. Anthracyclines based regimens (AC and FAC) are widely accepted as safe with PABC, long term studies on children exposed in utero are lacking. Taxanes safety is not documented, but weekly paclitaxel is widely accepted. G-CSF is considered safe. All new monoclonal antibodies such as Trastuzumab is contraindicated during pregnancy, endocrine therapy is contraindicated during pregnancy.

Radiation therapy, this must await the completion of pregnancy.

Breastfeeding, It is generally advised to pursue breastfeeding following the completion of therapy. Breast cancer contraindicated during chemotherapy, trastuzumab therapy, endocrine therapy or radiation therapy.



Summary of treatment

BreastMastectomy is the standard, breast conserving surgery my be considered in specific patient subsets.
AxillaBlue dye contraindicated.
Sentinel lymph node biopsy is not discouraged (controversial).
ReconstructionAfter delivery.
ChemotherapyAnthracycline-based regimens can be used in 2nd, and 3rd. trimester.
There are insufficient safety data regarding taxanes use. However, weekly paclitaxel following first trimester is acceptable.
Avoid chemotherapy 3 weeks before delivery or after 35th. week
Hormonal therapyContraindicated during pregnancy and breast feeding.
Monoclonal antibodies
(Trastuzumab etc.)
Contraindicated during pregnancy and breastfeeding
Radiation therapyContraindicated during pregnancy.

Summary of treatment by trimester (above table rules applies)

 Primary treatmentAdditional treatment
First trimester
Discuss termination (particularly in advanced stage disease)
Mastectomy plus axillary staging (see above table)Adjuvant chemotherapy to start in second trimester.
Adjuvant radiation therapy to start after delivery.
Adjuvant endocrine to start after delivery.
Second trimester
Early third trimester
- two possibilities.
Surgery first.Mastectomy or breast conserving surgery with axillary staging.Followed by adjuvant chemotherapy.
Adjuvant radiation therapy to start after delivery.
Adjuvant endocrine therapy to start after delivery.
Neoadjuvant chemotherapy first.
Anthracycline based me-adjuvant chemotherapy followed by surgery.Adjuvant radiation therapy after delivery.
Adjuvant endocrine therapy after delivery.
Late third trimester Mastectomy or breast conserving surgery with axillary staging.Adjuvant chemotherapy to start after delivery.
Adjuvant radiation therapy to start after delivery.
Adjuvant endocrine therapy to start after delivery.

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