Women who are breastfeeding are often acutely aware of how their breasts feel so they will usually notice any physical changes. It is common to find breast lumps during lactation, which can lead women to worry about breast cancer.

Women who know they have breast cancer are likely to have concerns about the safety of breastfeeding and may wonder whether their cancer treatment could affect the baby.

In this article, we provide more information about the relationship between breast cancer and breastfeeding.

Can you get breast cancer while breastfeeding?

It is possible to develop breast cancer while breastfeeding a baby, but it is rare. Breastfeeding women account for 3 per cent of breast cancer cases.

According to the National Cancer Institute, some research suggests that the risk of breast cancer is temporarily higher in the years following pregnancy and childbirth.

This increased risk may be the result of hormonal changes during pregnancy.

Overall, however, breastfeeding lowers the risk of breast cancer, especially in premenopausal women.

The months of pregnancy and breastfeeding will decrease the number of menstrual cycles that a woman has in her lifetime. This will reduce her exposure to hormones that can increase the risk of certain cancers.

Despite the low risk, women should speak with a doctor if they have any concerns about their breast health.

Several factors can make it more difficult for women who are lactating to get a breast cancer diagnosis. These include the following:

• Breastfeeding can cause issues that are very similar to the symptoms of breast cancer.

• Doctors may not think to test a woman for cancer if she finds a lump while breastfeeding as there are other possible causes.

• Mammograms and breast ultrasounds are more likely to give a false positive or inconclusive result during lactation.

What else can cause a breast lump while breastfeeding?

There are many conditions other than breast cancer that can cause a lump in the breast while breastfeeding. These include:

Engorgement

In the initial weeks of breastfeeding, it is common for the breasts to become overly full of milk, making them feel lumpy and uncomfortable. This is called engorgement.

Engorgement is common during the early stages of breastfeeding, but it can occur whenever there is incomplete draining of the breasts.

The symptoms of engorgement should go away as the breasts empty. The condition may also ease over time as the woman's body adjusts to the baby's demand for milk.

Plugged ducts

Special cells in the breasts produce the milk before it travels in small ducts to the nipples.

If the draining of the milk is too infrequent or the milk thickens, it can clog the duct. This can lead to trapped milk in the breast tissue, which may form a sore lump.

In most cases, frequent breastfeeding, breast massage, and warm compresses can help to resolve a plugged duct.

Mastitis

Mastitis is inflammation or infection of the breast. It is most likely to occur following engorgement or a plugged duct.

If the milk gets stuck in the breast, milk proteins can build up and eventually start to leak into the surrounding tissue.

In addition to a lump, mastitis can cause the following symptoms:

• redness on the breast

• fever

• shivers

• feeling unwell

A woman with mastitis should continue to breastfeed. Breastfeeding can help drain the trapped milk from the tissue, which is the best way to relieve symptoms.

Abscess

An abscess is a rare but dangerous complication of untreated mastitis. It is one of the ways that the body deals with an infection to prevent it from spreading throughout the body.

The centre of an abscess contains a pocket of pus and bacteria. Once an abscess forms, the infected tissue in the centre cannot escape.

An abscess needs urgent medical care, and treatment will include drainage and antibiotics. Anyone who thinks they may have an abscess should speak to a doctor as soon as possible.

Cysts

Small cysts, known as galactoceles, can sometimes form in the breast. They contain milk and may come and go depending on how much milk is in the breast.

These small lumps are not usually painful and will disappear once lactation is complete.

When should a woman go to the doctor with a breast lump?

In most cases, breast lumps in breastfeeding women are not cancerous and are no cause for concern.

However, a woman should see her doctor about a breast lump if:

• it does not go away

• it continues to grow

• pressing it does not make it move within the breast tissue

• it causes the skin to dimple or to resemble orange peel

A woman should also see her doctor if she has any concerns about her breast health in general.

Can a woman breastfeed if she has breast cancer?

In most cases, the doctor will recommend that a woman stops breastfeeding following a breast cancer diagnosis.

Many breast cancer treatments can affect a woman's milk supply or negatively impact on the baby.

The doctor will help to determine which treatment is best for an individual with breast cancer, as this can vary from person to person.

Possible treatments include:

• Surgery: Surgery may be necessary to remove a lump or cancerous growth. In some cases, this can involve a mastectomy (removal of the breast) or a double mastectomy (removal of both breasts). The extent of the surgery will determine whether or not the individual can continue breastfeeding.

• Chemotherapy: Chemotherapy uses strong medications to destroy cancer cells within the body. Women who are having chemotherapy will need to stop breastfeeding.

• Radiation: Some women undergoing radiation treatment may be able to continue breastfeeding, depending on the specific type of therapy. A doctor will be able to explain the risks to allow the individual to make an informed decision.

Breastfeeding during cancer treatment may be possible, but it is essential to speak to a doctor before and during the treatment process.

Takeaway

Developing breast cancer while breastfeeding is rare, but it is possible. Women should not hesitate to see their doctor if they have any concerns about their breasts.

In the event of a breast cancer diagnosis, the woman should discuss her options with the doctor, including whether or not she can continue to breastfeed.

Women should also make sure to have a regular checkup and clinical breast exam each year.