Breast cancer is the most prevalent type of cancer worldwide, with 2.3 million women diagnosed with this disease in 2020. In the United States, 1 in eight women will develop breast cancer at some point during their lifetime.
Breast cancer occurs in every country of the world. A post-pubescent woman of any age is at risk of getting it, though this risk increases with age. Breast cancers are named for where they start: ductal carcinoma originates in the milk ducts, while lobular carcinoma originates within or around the milk glands.
While you can’t change some breast cancer risk factors—family history and aging, for example—there are others that you can control to help reduce your risk.
This blog post will explore some of the main risk factors for breast cancer and some of the most common symptoms.
Lifestyle-related Risk Factors
Risk factors related to lifestyle are those that you can change or take steps to improve. The known risk factors include:
- Drinking alcohol
Current research suggests that having one or more alcoholic drinks per day is a known risk factor. Women who enjoy one drink per day have about a 10 percent increase in risk, while those who have two or three drinks per day see a 20 percent increase.
- Increased body weight
Women who are overweight or obese after menopause have a higher risk of developing breast cancer than those who maintain a healthy weight. The main reason for this is that after menopause, ovaries stop producing estrogen – it instead comes from fatty tissue within a woman’s body. The more fat tissue a postmenopausal woman has, the greater her estrogen levels. Therefore, overweight women have a higher risk of breast cancer because they are exposed to more estrogen in their bodies.
- Low physical activity
Every day, there is more and more scientific evidence that physical activity prevents breast cancer. According to the American Cancer Society, you should engage in regular physical activity (at least 150 to 300 minutes of moderate exercise per week). It leads to lower hormone levels, a healthier body weight, and positive changes in the immune system, reducing a woman’s risk of developing breast cancer.
- Pregnancy and breastfeeding
Research confirms that women who have children are less likely to develop breast cancer than women who don’t have kids. Additionally, women who have their first child over 30 are at a slightly higher risk than women who have children earlier in life.
However, the effect of pregnancy and reproductive history on the development of breast cancer is complex. For example, the risk of this disease increases in the first ten years after a full-term pregnancy, especially for hormone-receptor negative breast cancer.
Breastfeeding is linked with a lower risk of breast cancer, though the longer you nurse, the greater your benefit becomes.
- Birth control
It is unclear whether different birth control methods (birth control shots, IUDs, birth control implants, vaginal rings, etc.) increase a woman’s risk of breast cancer. Some studies show, for example, that women who have used birth control pills are at a slightly higher risk than those who haven’t, while others suggest the opposite is true.
In any case, it’s important to remember that estrogen from oral contraceptives has been linked with an increased chance of developing breast cancer and that the risk decreases after you stop using birth control.
Risk Factors You Cannot Change
- Being born a female
As mentioned in the introduction, a woman’s breast cancer risk is higher than her male counterpart’s. Breast tissue is the most common site for this disease to develop, and since males lack it from birth, they have a lower risk in general than women.
The older you are, the greater your risk for breast cancer. Most breast cancers are diagnosed in women 55 or older.
- Gene changes
About five to ten percent of all breast cancers are caused by specific gene changes known as mutations – BRCA being the most well-known of these. Mutations of the BRCA1 and BRCA2 genes lead to a 7 – 10% lifetime risk of developing breast cancer. Breast cancers associated with these mutations tend to develop at younger ages, and women who carry them have a higher chance of developing other cancers, especially ovarian cancer.
Other gene mutations that increase a person’s risk of breast cancer include PTEN, ATM, TP53, STK11, and others.
- Family and personal history of breast cancer
It is important to emphasize that most women who get breast cancer do not have a family history of the disease. Breast cancer is about twice as common among women whose mother or sister has been diagnosed with it than those who have no relatives affected by this condition.
Similarly, women who have had cancer in one breast are at an increased risk of developing cancer in the other breast or a different part of the same breast.
- Radiation to the chest
Radiation therapy to the chest, such as for diseases like Hodgkin or non-Hodgkin lymphoma, may increase the risk of developing breast cancer later in life. Breast cancers that develop due to radiation therapy are more prevalent in women who received their radiation before 30 or were treated with a high dose.
Breast Cancer Symptoms
Risk factors represent conditions that increase the chances of a breast cancer diagnosis, but no woman will automatically get this disease if she has one or more of the factors. It is essential to know the symptoms so you can get diagnosed and treated as early as possible.
Here are the most common symptoms of breast cancer:
- A lump in your breast that feels different from the rest of your breast tissue and may be hard to the touch. Breast lumps are often painless, but they can also be tender or sore.
- Breast swelling and enlargement not due to weight gain or fluid retention (which is common during pregnancy).
- Breast changes such as a nipple that turns inward into the breast or an inverted nipple, dimpling on the skin of your breasts, redness, or pitting in the area around your nipples.
- Redness, thickening, and scaliness on one side only.
- Nipple discharge (other than breast milk) not associated with breastfeeding.
- Swollen lymph nodes in the armpit or collarbone area.
Even if you are familiar with all potential signs and symptoms of breast cancer, it is important to see your doctor if you notice something that doesn’t seem right. Breast lumps are not always cancerous and can be caused by benign (not harmful) conditions such as cysts or fibroadenomas.
Regular screening also cannot be replaced with knowledge of your personal risk factors. Breast cancer screening in women over 40 reduces the risk of dying from breast cancer by about 25 percent, and early detection is key to successful treatment.
Even though breast cancer is the most common cancer among women, it is not necessarily a death sentence.
There are a number of risk factors related to breast cancer that can be controlled to some extent, and knowing your personal risk factors for this condition is essential to take the proper precautions.
If something doesn’t feel quite right with your breasts or if you notice any of the symptoms above, do not hesitate to contact your doctor. While breast cancer is a serious condition, it can be often successfully treated, especially when detected early.
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