Pregnancy associated breast cancer (PABC) refers to breast cancer that is diagnosed during pregnancy, during lactation (breast-feeding) or in the years following childbirth (post-partum).
It is the most common type of cancer that affects pregnant women.
There are two sub-classifications of PABC:
While breast cancer is the most common cancer in women, PABC is a rare type of breast cancer thought to affect about 1 in 3000 pregnant women.
There is an increasing incidence in the diagnosis of PABC, especially in women over 35 years.
The overall incidence of breast cancer generally increases with age. There is also a higher risk of being diagnosed with breast cancer following a pregnancy, especially in women over 35 years.
With women delaying pregnancy until a later age, as is more commonly seen in modern eras, there is a rising rate in the incidence of PABC, which makes it an important topic for education, discussion and research.
Most women with PABC present with a painless lump or thickening of the skin on the breast. The changes in the breast that occur during pregnancy, such as breast enlargement, often make it difficult to identify changes in the breast that might be caused by breast cancer. Unfortunately this can delay the diagnosis of PABC, with the cancer often detected at a more advanced stage and a worse outcome for patients.
Knowing your breasts is one of the most important things you can do to help detect changes. It is advisable to continue to do self-breast examinations throughout pregnancy.
Your doctor may recommend several tests to confirm a diagnosis of PABC such as:
The treatment of pregnancy-associated breast cancer is determined by a number of factors including the stage of breast cancer, how advanced the pregnancy is as well as the individual medical history and personal preferences for treatment.
There is no evidence to suggest that termination of the pregnancy in the first or second trimester results in better outcomes for the patient.
If a diagnosis of PABC has been made close to the end of the pregnancy, it may be an option for the patient to proceed with delivery before treatment is commenced.
Women who are diagnosed with breast cancer during pregnancy should speak to their oncologist about the best treatment option for them.
Treatment options include:
Breast surgery can be performed at any time during pregnancy and is considered to pose little or no harm to the unborn baby.
Studies have shown that chemotherapy can be safely given during pregnancy, as long as it is after first trimester. However, it should be withheld in the last three weeks before delivery to allow both maternal and foetus’s blood counts to return to normal. Careful planning and discussion between the patient, oncologist and obstetrician will be needed to plan for the chemotherapy while maintaining safety of the pregnancy with attention to timing of delivery.
Radiation therapy should be avoided during pregnancy, but could be considered an option for treatment following delivery if the pregnancy is close to term.
| Trimester of pregnancy | Possible treatment options |
| First | Surgery |
| Second | Surgery, chemotherapy |
| Third | Surgery, chemotherapy (stopped by 35 weeks) |
PABC diagnosed in postpartum years appears to have a more aggressive nature and typically worse outcomes.
It is suggested that this may be linked to the process of cell changes that occurs in the breast cells following weaning as the breast returns to the pre-pregnant state, creating a tumour-promoting microenvironment.
Women who are diagnosed in the postpartum years should speak to their oncologist about the best treatment options available, including clinical trials.