If you’re breastfeeding a baby, you may be concerned about the health of your breasts. Some women wonder if they can develop breast cancer while lactating. Although rare, it’s a possibility.

Read on to learn how to spot breast cancer while you’re breastfeeding and what treatments are available.

What causes lumps in lactating women?

Women who breastfeed may feel lumps in their breasts. Most of the time, these lumps aren’t cancerous. Breast lumps in lactating women may be due to:


Mastitis is an infection of the breast tissue caused by bacteria or a blocked milk duct. You may have symptoms such as:

  • breast tenderness
  • swelling
  • pain
  • fever
  • skin redness
  • skin warmth

Breast abscesses

If mastitis isn’t treated, a painful abscess containing pus can develop. This mass might appear as a swollen lump that’s red and hot.


Fibroadenomas are benign (noncancerous) tumors that can develop in the breast. They may feel like marbles when you touch them. They usually move under the skin and aren’t tender.


These harmless milk-filled cysts are typically painless. In general, noncancerous lumps feel smooth and round and move within the breast. Cancerous lumps are usually hard and irregular in shape and they don’t move.

Early symptoms of breast cancer

Lumps aren’t the only sign of breast cancer. Other early symptoms may include:

  • nipple discharge
  • breast pain that doesn’t go away
  • change in size, shape, or look of the breast
  • redness or darkening of the breast
  • itchy or sore rash on the nipple
  • swelling or warmth of the breast


Breast cancer in lactating women is rare. Only about 3 percent of women develop breast cancer while breastfeeding. Breast cancer in younger women isn’t very common either. Less than 5 percent of all breast cancer diagnoses in the United States are in women younger than 40.

When to see a doctor

You should see a doctor if the lump in your breast:

  • doesn’t go away after about a week
  • comes back in the same place after treatment for a blocked duct
  • keeps growing
  • doesn’t move
  • is firm or hard
  • causes dimpling of the skin, also known as peau d’orange

Lactation can cause changes in your breasts, which may make noticing symptoms of cancer tricky. It’s a good idea to see your doctor if you notice any unusual changes in your breasts.

How breast cancer is diagnosed

If your physician suspects breast cancer, they’ll perform certain tests to make a diagnosis. A mammogram or ultrasound can provide images of the lump and help your doctor determine if the mass looks suspicious. You might also need a biopsy, which involves removing a small sample from the lump to test for cancer. If you’re lactating, a radiologist might have a harder time reading your mammogram. Your doctor may recommend you stop breastfeeding before having diagnostic tests, but this advice is somewhat controversial. Most women can have screening procedures such as mammograms, needle biopsies, and even certain types of surgery while breastfeeding a baby. Talk to your doctor about the benefits and risks of breastfeeding while receiving diagnostic tests.

Treatment while breastfeeding

If you have breast cancer while lactating, you may need surgery, chemotherapy, or radiation. Your doctor will help you decide which treatments are best for your particular condition.

Surgery and breastfeeding

You may be able to continue breastfeeding before and after having surgery to remove your tumor depending on the type of procedure. Talk to your doctor about whether it’s safe for you and your baby to continue breastfeeding. If you have a double mastectomy, you won’t be able to breastfeed. Treating a breast with radiation after a lumpectomy means it usually produces little or no milk. You may be able to breastfeed with the untreated breast, however. Ask your doctor what medications you’ll receive before and after surgery and if they’re safe for a baby who’s breastfed. You might need to pump your milk and discard it for a period of time before resuming breastfeeding.

Chemotherapy and breastfeeding

If you need chemotherapy, you’ll have to stop breastfeeding your baby. The powerful drugs used in chemotherapy can affect how cells divide in the body.

Radiation therapy and breastfeeding

You might be able to continue breastfeeding while receiving radiation therapy. It depends on the type of radiation you have. Some women can breastfeed with the unaffected breast only.

Treatment side effects

It’s important to remember that you could experience side effects from treatment. These might include:

  • fatigue
  • weakness
  • pain
  • nausea
  • weight loss

You may want to request help with childcare so you have time to rest and recover.


Breast cancer in younger women tends to be more aggressive, but an early diagnosis can improve your outlook. Your risk of developing breast cancer while lactating is low, but if you’re diagnosed with cancer, you might be able to continue breastfeeding your child. Talk to your doctor about the best options for your unique situation. Your team of doctors can help you decide whether breastfeeding during your cancer treatment is a good option for you and your baby.

Emotional support

There are many decisions to make when you’re diagnosed with breast cancer. Electing to stop or continue breastfeeding may be a difficult choice. If you decide to continue breastfeeding, you might want to find a lactation specialist to help you deal with any challenges. Reaching out for emotional support can help you manage your diagnosis, as well. Surround yourself with family, friends, and a good medical team to create a support system. You may also want to reach out to others in an in-person or online support group.