If you or a loved one has been diagnosed with breast cancer, it’s important to understand some basics: What is breast cancer and how does it happen?
In this section, you can learn about how breast cancer develops, how many people get breast cancer, and what factors can increase risk for getting breast cancer. You also can learn more about signs and symptoms to watch for and how to manage any fears you may have about breast cancer.
"Breast cancer is never anyone’s fault. Feeling guilty, or telling yourself that breast cancer happened because of something you or anyone else did, is not productive."
What Is Breast Cancer?
Breast cancer is an uncontrolled growth of breast cells.
To better understand breast cancer, it helps to understand how any cancer can develop.
Cancer occurs as a result of mutations, or abnormal changes, in the genes responsible for regulating the growth of cells and keeping them healthy. The genes are in each cell’s nucleus, which acts as the “control room” of each cell. Normally, the cells in our bodies replace themselves through an orderly process of cell growth: healthy new cells take over as old ones die out. But over time, mutations can “turn on” certain genes and “turn off” others in a cell. That changed cell gains the ability to keep dividing without control or order, producing more cells just like it and forming a tumor.
A tumor can be benign (not dangerous to health) or malignant (has the potential to be dangerous). Benign tumors are not considered cancerous: their cells are close to normal in appearance, they grow slowly, and they do not invade nearby tissues or spread to other parts of the body. Malignant tumors are cancerous. Left unchecked, malignant cells eventually can spread beyond the original tumor to other parts of the body.
The term “breast cancer” refers to a malignant tumor that has developed from cells in the breast.
Usually breast cancer either begins in the cells of the lobules, which are the milk-producing glands, or the ducts, the passages that drain milk from the lobules to the nipple. Less commonly, breast cancer can begin in the stromal tissues, which include the fatty and fibrous connective tissues of the breast.
In some cases, however, the first sign of breast cancer is a new lump or mass in the breast that you or your doctor can feel. A lump that is painless, hard, and has uneven edges is more likely to be cancer. But sometimes cancers can be tender, soft, and rounded. So it’s important to have anything unusual checked by your doctor.
According to the American Cancer Society, any of the following unusual changes in the breast can be a symptom of breast cancer:
•swelling of all or part of the breast
•skin irritation or dimpling
•nipple pain or the nipple turning inward
•redness, scaliness, or thickening of the nipple or breast skin
•a nipple discharge other than breast milk
•a lump in the underarm area
These changes also can be signs of less serious conditions that are not cancerous, such as an infection or a cyst. It’s important to get any breast changes checked out promptly by a doctor.
In reality, about 1 in 8 women — or 13%, or 13 out of every 100 — can expect to develop breast cancer over the course of an entire lifetime. An average lifetime is about 80 years. So, it’s more accurate to say that 1 in 8 women. who reach the age of 80 can expect to develop breast cancer. In each decade of life, the risk of getting breast cancer is actually lower than 13% for most women.
People tend to have very different ways of viewing risk. For you, a 1-in-8 lifetime risk may seem like a high likelihood of getting breast cancer. Or you may turn this around and reason that there is a 7-in-8, or 87.5%, chance you will never get breast cancer, even if you live to age 80. How you view risk often depends on your individual situation — for example, whether you or many women you know have had breast cancer, or you have reason to believe you are at higher-than-normal risk for the disease — and your usual way of looking at the world.
Even though studies have found that women have a 13% lifetime risk of developing breast cancer, your individual risk may be higher or lower than that. Individual risk is affected by many different factors, such as family history, reproductive history, lifestyle, environment, and others.
This section is designed to help you better understand breast cancer risk and some of the factors that can increase risk.
Breast cancer is always caused by a genetic abnormality (a “mistake” in the genetic material). However, only 5-10% of cancers are due to an abnormality inherited from your mother or father. About 90% of breast cancers are due to genetic abnormalities that happen as a result of the aging process and the “wear and tear” of life in general. While there are steps every person can take to help the body stay as healthy as possible (such as eating a balanced diet, not smoking, limiting alcohol, and exercising regularly),