After some intense research on the risk of developing breast cancer, I’ve come to the conclusion that the factor with the greatest causal relationship to the disease is, quite frankly, life. In fact, I sometimes wonder how people manage to NOT get cancer.
For your reading pleasure, I surveyed a number of reputable sites to compile a list of commonly accepted breast cancer risk factors (links to the info): American Cancer Society, Mayo Clinic, Memorial Sloan Kettering Cancer Center, Dana Farber Cancer Institute, Centers for Disease Control, National Breast Cancer Foundation, World Cancer Research Fund and WebMD. There are some emerging risks that most sites didn’t list and although I have seen the research studies in support of those factors, I opted to exclude specifics for now. Perhaps that’s for a future post.
Here you go, not in exact order of importance:
- Being born female (well that covers about 50% of us)
- Getting older (um, inevitable…)
- Drinking alcohol (even moderate drinking has been shown to be harmful – find a different hobby)
- BRCA1 and BRCA2 gene mutations, which everyone talks about, but certain mutations in the following may also increase cancer risk, although to a lesser extent: ATM, TP53, CHEK2, PTEN, CDH1, STK11, PALB2
- Personal history of breast cancer (get it once and you’re a moving target)
- Family history of breast cancer (including both close and distant relatives)
- Personal history of breast lesions (even stuff that seemed benign-ish)
- Radiation exposure, specifically to the face and chest, before the age of 30
- Obesity (but mainly for postmenopausal women, see here; it’s complicated)
- Having dense breasts (sometimes this is considered a top risk factor)
- Beginning your period before age 12
- Going through menopause after age 55
- Having your first child after age 30
- Never having kids (remember that when you’re paying for their college)
- Taking hormone replacement therapy (HRT)
- Certain hormonal birth control methods
- Family history of ovarian cancer, especially before age 50.
- Being white (at least in the U.S., although the rates of African-American women are catching up, often with a worse prognosis)
- Having received diethylstilbestrol (DES) to prevent miscarriage, given either to you or your mother
- Being inactive (honestly, exercise is critical – don’t overthink it – MOVE!)
- Not breastfeeding (not only does nursing lower your risk, if you do get breast cancer, you’re less likely to get the aggressive triple-negative type)
- Being taller (this may have to do with faster growth at an early age)
- Doing night shift work (this may affect your hormone patterns, not to mention make you cranky during the day)
- Smoking (the evidence for this has been deemed “suggestive, but not sufficient”, but inhaling smoke sounds like a bad idea regardless)
- Exposure to cancer-causing chemicals (that’s, like, just about everything out there, and the connection remains unclear)
- Diet choices (this is unclear, although there have been some links drawn to both macronutrient proportions and some vitamins, but more research must be done)

In a word, we really don’t know, but living a healthy lifestyle gives you the best chance for survival.
Finally, the things that seem to have no reasonable link (per WebMD and echoed on other sites):
- Antiperspirant (no need to stink)
- Bras, underwire and regular (feel free to support yourself)
- Abortion or miscarriage
- Fibrocystic breast changes
- Multiple pregnancies
- Coffee/caffeine (raise your mug in celebration!)
- Hair dye (unless it’s really radioactive, but come on, that would be silly)
Judging from the above info, it can feel like cancer is waiting around the corner to pounce on the next unsuspecting victim that wanders by. I thought I had ZERO risk factors, but I can easily pick out several there. At the same time, I know people who seem like they’d have a gazillion risk factors and they never get zapped. So.not.fair. But that’s cancer for you.
And the more we find out about the disease, the more we see how complex it is. We are all different, reflected by our DNA, so it’s not out of the question that we might be affected in unique ways by these risk factors. Research is uncovering new connections all the time, and it may be that in order to find a cure for cancer, we’re going to have to look at the disease in ways that we never have.