Breastfeeding and breast cancer

Dr Sumayya Ebrahim talks about how breastfeeding can protect you from developing breast cancer.

What do your breasts mean to you? Do they symbolise your femininity or emphasise your role as a mother since you nourish and feed your child with one of the most nutritious substances on this planet? Just by carrying out the function of producing milk, your breasts set up a cascade of outcomes that protects itself and you from developing breast cancer.

Breastfeeding lowers the risk of breast cancer: the evidence

The consensus is that breastfeeding has many benefits. Protecting your baby from infections and developing a good immune system is just the start; fostering an enhanced bonding experience between mom and baby is another, and protection against breast cancer is an excellent bonus.

In 2002, a study published in The Lancet, found that the longer the breastfeeding, the more the cancer-protective effect: for every 12 months of breastfeeding (either with one child or  spread out with multiple children) the risk of the breastfeeding mom decreased by 4.3%. Mothers who breastfed for a total of two years procured about twice the benefit. Breastfeeding for longer than two years was associated with even more of a benefit, compared to women who did not breastfeed at all. This study pooled together 47 studies from 30 countries and involved an analysis of nearly 150 000 women.

A later study in 2009, in Archives of Internal Medicines, found that if a woman with a family history of breast cancer breastfed, she would reduce her chances of getting early breast cancer before menopause by 60%.

In 2015, a recent publication in Annals of Oncology, showed a protective effect of breastfeeding on hormone receptor negative breast cancer. The research and evidence exists; breastfeeding reduces the risk of breast cancer.

How does breastfeeding protect you from breast cancer: the theories

Many theories exist, however, researchers are still not sure how all of it fits together. The theories described below make some impact against cancer.

• Breastfeeding moms have fewer menstrual cycles; this means less exposure to oestrogen, which has been linked to fuel the growth of some breast cancers.

• Breast milk contains a substance called alpha-lactalbumin. When this compound mixes with oleic acid in the body, a product called HAMLET is formed. HAMLET is unique. It is a real superpower as it targets and destroys cancer cells, but has an amazing ability to leave normal cells unharmed. Watch this space – studies are underway to use HAMLET in non-breastfeeding women as a vaccination against breast cancer.

• Breastfeeding activates a tumour suppressor gene called P53, which suppresses the formation of certain cancers. Thus breastfeeding is like immunising yourself and your baby to some extent against breast cancer.

• Breastfeeding protects against certain gene mutations that favour cancer formation.

Breastfeeding after a breast cancer diagnosis: the truth

Breastfeeding can be a challenge even at the best of times. Throw a breast cancer diagnosis into the equation and matters get complicated. Some mothers’ may choose not to breastfeed at all and focus their energies on the treatment instead, whilst few mothers may decide to still feed despite everything. The choice is theirs, however, the following factors need to be taken into consideration:

• If you are on tamoxifen or chemotherapy, it is not safe to feed. The drugs may cross over to your new-born.

• If you had surgical treatment, like a mastectomy or lumpectomy, with or without radiation you may only be able to feed from the opposite breast. The affected breast may not produce enough milk, especially if breast tissue has been removed or radiated.

• Due to contour changes in the breasts after radiotherapy, a baby may also have difficulty latching on