Do Docs Miss Breast Cancer Warning Signs in Breastfeeding Mothers?

We are so excited to share this guest post by Dr. Shannon Tierney, Breast Oncology Surgeon at the Swedish Cancer Institute in Seattle, Washington.  We loved her story about how her interest in breastfeeding developed (“How a Surgeon Ended up in the Academy of Breastfeeding Medicine”) and were motivated by Jamie Thomas‘ breast cancer story to help more moms (you can help too).  We’re so grateful for the time Dr. Tierney has taken to share the important – but surprisingly hard-to-find – information below. 

In the haze of joy and sleeplessness during the months after childbirth, thoughts about breast cancer are the last thing on a new mother’s mind. Her body is undergoing so many changes that, of course, she and her doctors would naturally assume any breast changes are related to breastfeeding.

Probably, they are.  However, there is a small but real incidence of women who develop breast cancer during and following pregnancy. Often, they end up having delays in seeking evaluation and getting a diagnosis, because they or their doctors may not appreciate that risk!

So, what things should prompt an evaluation?

  • Lumps – most often will be changes in the breast tissue as it revs up milk production. A distinct lump or “dominant mass” could be a clogged duct, galactocele, cyst or a common benign tumor called a fibroadenoma, but if it doesn’t resolve within a few weeks with treatment, it needs imaging.
  • Redness – most often will represent infections like mastitis or an abscess, but if it doesn’t resolve within a few weeks with treatment, it will also need imaging and possibly a biopsy. At the very least, that could determine if the right antibiotics are being used. An uncommon form of breast cancer called inflammatory breast cancer can present this way.
  • Bloody milk or baby refusing one breast – most often will be due to nipple trauma, latch issues, or positioning; if so, seeing a board-certified lactation consultant is appropriate. But rarely, this can represent a form of breast cancer within the milk ducts.
  • “Something’s not right” – you are the most knowledgeable person about your own breasts. Even if it doesn’t neatly fit one of the categories above, if something really seems wrong to you, your doctors should take that seriously.

What evaluation should be done?

  • Mammogram CAN be done in a breastfeeding woman. Ideally, it should be done with an experience mammographer who knows the woman is breastfeeding, as the images will be more complex. She should empty her breasts as much as possible right before the mammogram, either by nursing or pumping.
  • Ultrasound CAN be done in a breastfeeding woman. Same issues apply. Ultrasound, incidentally, can actually be somewhat useful therapeutically for breaking up a clogged duct.
  • MRI CAN be done in a breastfeeding mother, though it is not recommended just for routine screening (as is done in high risk women) because the sensitivity is lowered. Gadolinium, the dye used for MRIs of the breast, barely gets into milk and is not absorbed by the baby’s gut, so it is safe – no need to pump and dump.
  • Milk cytology can be done, but it’s often low-yield. It does have the advantage of being noninvasive, but needs a specialized pathologist and doesn’t usually rule out cancer.
  • Needle biopsies (fine needle aspiration and core biopsy) CAN be done in a breastfeeding mother. The smallest needle that will get the diagnosis should be used, but the risk of milk fistula, which is chronic milk leakage, is very rare.  There is no research on the incidence of milk fistulas with biopsies, but it’s rare enough that when it happens it gets written up as case reports!  Incisions around the areola should avoid the lower outer border to keep from injuring the
    4th intercostal nerve, and radial incisions (or an approach similar to what is done for C-sections, where the skin incision is made to be cosmetic and the inner dissection is done in a radial fashion) are recommended. The breast should be kept well drained with nursing or pumping before and after. Use of a local anesthetic like lidocaine is safe – no need to pump and dump.
  • Surgery on the breast CAN be done in a breastfeeding mother. Milk fistula is still a risk, though that risk may not be reduced much by weaning as the breast could continue to make milk for months after weaning. The surgeon should be very careful with her technique – minimizing unnecessary damage to the milk ducts and avoiding the central breast if possible. Radial incisions and avoiding the 4th intercostal nerve (see above) are recommended.  The breast should be kept well drained with nursing and pumping before and after. Most types of anesthesia will be out of the milk by the time the patient is awake and alert – at most, pump and dump once.

Breastfeeding has the potential to reduce lifetime cancer risk anywhere between 5-59% but is not a risk-free window. Women who have a concern should not be dismissed just because they are breastfeeding, nor should their health care providers overreact and encourage early weaning in order to get them evaluated.

When we know how to evaluate the “working” breast properly, we can ensure that fewer women experience delays in diagnosis and more women can continue to breastfeed successfully.

15 thoughts on “Do Docs Miss Breast Cancer Warning Signs in Breastfeeding Mothers?

  1. A friend of mine was diagnosed with Inflammatory Breast Cancer (IBC) while nursing her second son. Her cancer was misdiagnosed as mastitis for several weeks at the beginning. One other tell-tale sign to look for in IBC is that the skin begins to take on a slight puckering look, similar to that of an orange peel.


  2. I was just diagnosed this week with triple negative breast cancer in my left breast. I have been exclusively breastfeeding my 7 month old as I did my other, now teenage, children. I am very nervous about my upcoming surgery. My surgeon is thinking of doing chemotherapy prior to surgery while I attempt to wean. Any thoughts on this would be greatly appreciated.


    1. I was diagnosed with breast cancer last month and am having chemo first. I am nursing my 18 month old and am struggling to wean him. Anyone have pointers on how to wean quickly?

      As for Val, have that mammo!!! I had mammograms, ultrasounds, breast MRI and other tests. It is your right to insist. Or find another doctor


    2. its is possible to had a breast cancer even if you are exclusively breastfeeding?? i am affraid because i had an unsual pain in my right breast and im exclusively breastfeed my 1 year old son?


  3. Hi, my dr found a rather large lump in my right breast. I had an ultrasound done and they didn’t find anything. They said they refuse to do a mammogram on a lactating woman. I am afraid they may miss something and I have read that it is ok to do a mammogram. What do I do to insist furture tests on this. I am so nervous. Thank you.


  4. I don’t understand how it’s safe to expose your breasts to radiation ever, especially while your baby is ingesting the milk. This article does not mention thermography, which has been a safer alternative to the mammogram for a while now. Is thermography an option while breast feeding?


  5. I haven’t seen concern by breastfeeding mothers (with breast cancer) about the risk of cancer cells being ingested by their nursing babies. Also, is the milk of mothers with cystic breast disease safe for their babies?


  6. Addressing some concerns posted here –

    The radiation administered during a mammogram is transient. It is not like ingesting a radioisotope – it does not make milk radioactive, even momentarily. Breast thermography, currently, is not recommended for screening. There are huge variations in the sensitivity and specificity in published studies (Sens 0.25-0.97, Spec 0.12-0.85), so while some suggest it may be very good, others suggest it is a dismal alternative that can miss most cancers and falsely identify too many non-cancers. [Vreugdenburg, Breast Cancer Res Treat, 2013.] Trust me, as a woman, I’d love a viable alternative to mammograms!

    Regarding the safety of milk, there is no evidence of any risk to babies who ingest milk from moms with breast cancer or benign breast disease. Most chemotherapy drugs are not safe for breastfeeding babies, but additional information can be gotten from Hale’s Medications and Mother’s Milk.


  7. Hi Dr. Tierney,

    Thank you for this article. I am breast feeding and have had a palpable lump that is immovable, has changed and affixed to my breast. It has been there since before I was even pregnant but puckers outward when the breast is engorged with milk.

    I had it checked thoroughly via ultrasound, but the techs and radiologist insisted it all looks like normal tissue, no need for mammogram or for follow-up until next year. (My sister is a survivor.)

    My instincts, family history, and the way it feels have prompted me to get a second opinion. Do you have any recommendations for someone who is comfortable with the lactating breast who can assess the lump??



  8. This is a very serious topic. My wife was breast feeding our 3mo daughter and sought help for a lump. Diagnosis was delayed about 9 months. She died 2 years later. The radiologist did not perform a mammogram even though it was requested by the referring doctor, telling my wife that it was not possible. The ultrasound report was inconclusive and recommended a short term followup, but he verbally reported to my wife that everything was OK. It turns out that short-term followups are not recommended in guidelines. Better to determine things conclusively at the initial consultation. At any rate the followup request did not reach my wife from her consulting doctor until much later, and the second radiology report was miscommunicated to her. By the time she was properly diagnosed the cancer had spread. After her death, the only medical expert I could get on record until my money ran out said that the radiologist’s approach was reasonable, and that the cancer would have probably spread by the initial radiology exam anyway. I have my doubts about that! I don’t think my wife received the attention she deserved. I don’t think breast feeding women are getting the attention they deserve. So much is at stake. If you’re concerned, push your doctors until it is completely sorted out, and you have no doubts left. Don’t let them be wishy washy. My daughters lost their mum when they were 3yo and 4yo.


    1. I have had swollen lymph nodes in my neck & armpit for months & had a CT scan and follow up PET scan which showed more in subpectoral region. The PET scan showed up take in my breasts but since I am nursing it is assumed that is the reason. Is this incorrect? I have fatigue & have lost 15lbs unintentionally. My blood work shows neutropenia & I have experienced hair loss.


  9. I have had a breast lump for 3 months now. My pcp ordered an US. That came back inconclusive. She said it was probably an abscess and to take antibiotics and do a follow up US. I told her I have not had mastitis or any indications of a breast infection. I only have the lump. She said because the mass is so deep in my tissue that it could be ab absecess that doesn’t display typical symptoms. The antibiotics did nothing and the US was still inconclusive. My pcp said since I’m breastfeeding that she isn’t worried about how the lump looks and it is probably an absecess that is unresponsive to the type of antibiotics we used. She said I needed an mri next. My insurance denied the request. Now the opposite breast has all of my lymphnodes swollen by my armpit and it is super painful. My main question is… Is it possible to have an abscess with absolutely no symptoms of one? Besides a painless lump, deep in the tissue, not visible from the outside?


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