10 factors that increase your risk of breast cancer
By Alyssa Quimby, MD
October is breast cancer awareness month. So for all of those reading who are 40 and over, please schedule your mammogram if you haven’t already had it this year.
Mammograms are the number one way we detect early breast cancer. In fact, mammograms are thought to detect breast cancer 1 to 4 years before you or your doctor would even be able to feel a lump on exam!
There are several risk factors that may increase your chances of breast cancer and it’s important to be aware of these.
#1 – Age
By far, age is one of the most important risk factors. At 40 is when the risk of breast cancer begins to increase which is why mammograms are recommended starting at this age by ACOG (the American Congress of OB/Gyn). But at age 60 your risk of breast cancer doubles and at age 70 it triples! Unfortunately, we do see breast cancer in younger women, often those with other risk factors for cancer. The overall lifetime risk of breast cancer is one in eight.
#2 – Sex
Not surprisingly, female sex is a risk factor for breast cancer. Females are 100x more likely than males to get breast cancer
#3 – Race
White/Caucasian race is a risk factor for breast cancer. White women are more likely to get breast cancer but unfortunately black women are more likely to have more aggressive, more advanced breast cancer.
#4 – Weight
In women who have gone through menopause, higher weight is associated with an increased risk of breast cancer.
In premenopausal women, this is the opposite – lower weight is associated with an increased risk of breast cancer.
#5 – Height
Tall stature is surprisingly a risk factor for breast cancer. Women who are 5’9” or taller are 20% more likely to develop breast cancer than women who are 5’3” or shorter.
#6 – Breast density
Increased breast density which is diagnosed on mammogram and is somewhat based on the fat composition of your breasts, increases your risk of breast cancer. It also makes early breast cancer more difficult to detect on mammogram. If you have had a mammogram previously that noted your breasts to be dense, make sure to talk to your doctor about this. You may be a candidate for additional imaging depending on your other risk factors.
#7 - Breast cysts or other benign masses
Thankfully, most benign breast masses do not increase your risk of breast cancer. These include breast cysts which feel like a small water balloon within your breast tissue, fibroadenomas which often feel like a round, smooth, marble, or intraductal papillomas which can cause nipple discharge. Breast masses that do increase your risk of breast cancer are called proliferative lesions with atypia – meaning the cells don’t look normal and grow faster than expected (similar to cancer). Examples of these lesions include: atypical ductal hyperplasia and atypical lobular hyperplasia. Because these types of masses are linked to cancer, it’s recommended for them to be completely removed and for patients to undergo increased screening.
#8 – Family History
Because breast cancer is so common, almost every woman has a family history of breast cancer.
But when breast cancer occurs in first degree relatives (your mother, sister, or daughter), this is when it increases your risk more significantly.
Having a first degree relative with breast cancer doubles the risk and having 2 first degree relatives with breast cancer triples the risk.
#9 – Having children
Interestingly, having children generally has a protective effect against breast cancer. Women who have given birth are less likely to develop breast cancer compared to women of their same age who have not given birth. But maternal age at the time of birth seems to play an important role. The younger you are at the time of your first delivery, the more protection you seem to have. Women giving birth to their first child at 20 are 20% less likely to develop breast cancer compared to women who give birth at 25 who are 10% less likely to develop breast cancer. And for those who give birth at 35 or older, the risk of breast cancer is similar to women who never had children.
#10 – Using birth control or hormone replacement therapy
I get asked this question all the time – “Will being on hormones increase my risk of breast cancer in the future?” And the answer is…it depends.
For women using oral contraceptive pills this does slightly increase your chance of breast cancer while on the pill. Though remember for most women using the pill in their 20s and 30s – your baseline risk of breast cancer is VERY low. This risk goes away completely between 2 to 5 years after stopping the pill.
As for hormone replacement therapy (HRT) – women who are taking combined HRT with estrogen and progesterone (which you need unless you’ve had a hysterectomy) are at slight increased risk of breast cancer. The Women’s Health Initiative study estimates 3 additional cases per 1000 women due to HRT use over a 5 year period. It’s thought that after HRT is stopped, the risk of breast cancer does decrease but is still slightly higher compared to women who never used HRT. And for women who don’t have a uterus and can be on estrogen replacement alone, there is no increased risk of breast cancer.
Unfortunately, breast cancer is common. But by getting our screenings on time and being aware of any of our additional risk factors, this allows us to be educated and to advocate for ourselves and our health.
