The potential problem
If you've recently been diagnosed with a malignant (cancerous) tumor of the breast or other area of the body that must be removed immediately, treatment of the cancer may affect your ability to nurse.
If you were treated with radiation to the breast or chemotherapy in the past, you may worry that it has damaged your glands or ducts or otherwise affected your ability to produce breast milk.
Can I breastfeed?
Undergoing treatment now: Nursing is safe during diagnostic tests for cancer such as a mammogram (although it may be harder to read during lactation), X-ray, CAT scan, MRI, ultrasound, and biopsy.
If you undergo radioactive isotope therapy or chemotherapy, however, you must stop breastfeeding until the radioactive elements or medications are completely gone from your body.
You can still nurse if you are having radiation therapy, but having had radiation will limit milk production in the affected breast.
Learn how having a lumpectomy or mastectomy will affect your ability to breastfeed.
Cancerous cells cannot be passed to your baby through breast milk.
Past history of cancer: If you've had cancer in the past, ask your healthcare provider how long it will take for chemotherapy drugs and other medications to leave your system. Once the medications are gone, it's fine for you to nurse.
Don't postpone surgery or other treatment to prolong nursing – it may put your life in danger. Instead, talk to your doctor about feeding options that are safe for you and your baby. For example, in certain cases of breast cancer, you may be able to continue nursing from the unaffected breast. Or you may consider "pumping and dumping" – pumping to keep your milk supply going and then throwing away the milk until you can safely breastfeed again.