This year, the American Cancer Society estimates that over 246,000 new cases of invasive breast cancer will occur and over 40,450 women will die from the disease. Excluding cancers of the skin, breast cancer is the most frequently diagnosed cancer in women – about 1 in 8 women will experience breast cancer during their lifetime.
With October marking the observance of National Breast Cancer Awareness month, now is a good time to better understand this disease and learn what you can do to lower your risk.
What is Breast Cancer?
Cancer is the broad term for a group of diseases that are the result of abnormal cells growing and spreading (metastasizing) to invade healthy cells in the body.
Cell replication is a normal part of the cell cycle that is constantly taking place among the trillions of cells in the human body. Sometimes, the replication process doesn’t go smoothly and a piece of DNA is damaged, causing mutations to occur.
Think of it as trying to read a message from a photocopy of a photocopy of a photocopy – pieces of the original message may look altered or not come through at all.
This change in DNA alters the cell cycle, causing new cells to form when the body doesn’t need them, or preventing old and damaged cells from dying properly. As cells continue to replicate with the damaged DNA, they build up into a growth or mass of cells to form a tumor.
Benign tumors, despite being extremely common (9 out of 10 women develop benign breast tissue changes) are rarely a serious cause for concern because they do not spread to surrounding tissue. Even so, benign tumors should be monitored for changes over time that may signal the cells are becoming cancerous.
Malignant tumors, on the other hand, are cancerous – they do spread. In breast cancer, it is malignant tumors that develop in breast tissue and invade blood and lymph vessels to branch out into other areas of the body, causing tissue and organ damage.
According to the American Cancer Society, the most common forms of breast cancer are:
Ductal carcinoma in situ (DCIS). Breast cancer in the duct cells that has not invaded deeper or spread through the body. Women diagnosed with DCIS have a high likelihood of being cured.
Lobular carcinoma in situ (LCIS). Although called a carcinoma LCIS, which occurs in the milk-producing lobule cells, it does not invade or spread and is thus not a true cancer. However, women with LCIS have an increased likelihood of developing invasive breast cancer in the future.
Invasive ductal carcinoma. Breast cancer that begins in the duct cells but then invades deeper into the breast, carrying the potential of spreading to the rest of the body (metastasizing). Invasive ductal carcinoma is the most common type of invasive breast cancer.
Invasive lobular carcinoma. Breast cancer that begins in the milk-producing lobule cells, but then invades deeper into the breast, carrying the potential of spreading to the rest of the body (metastasizing). Invasive lobular carcinoma is an uncommon form of breast cancer.
Some less common forms include inflammatory breast cancer, triple-negative breast cancer, and Paget disease of the nipple, but these are extremely rare and generally occur in less than 3% of breast cancer cases.
What are the Risk Factors?
Your unique genetic background and medical history are the best place to start when looking at your personal risk for breast cancer. Both the National Cancer Institute and the Harvard Center for Cancer Prevention offer risk assessment tools on their websites to help start your investigation.
Several factors have been identified that may increase your risk, yet the chance you will develop breast cancer largely depends on your lifetime exposure to estrogen.
Here are some other primary risk factors to take into consideration:
Sex. Although breast cancer mainly affects women, 1% of new breast cancer cases and deaths are in men. Perhaps because of this female association, men are more likely to receive a late stage diagnosis.
Age. Your risk of developing breast cancer increases with age. At age 30, your chances are 0.43% or 1 in 234. Compare that to your risk at age 70 of 3.9% or 1 in 26.
Long Menstrual History. Early periods (before age 12) and late menopause (over age 55) expose a woman to estrogen over a longer period of time. This increased exposure to circulating estrogen is linked to increased risk for breast cancer.
Late Pregnancy or No Pregnancy. Women who give birth after age 30, who have fewer pregnancies or who never have children, have a higher risk for breast cancer.
Personal or Family History. If you’ve already had breast cancer, then your risk of a recurrence is higher. Likewise, your chances for a diagnosis increase if someone in your family has experienced breast cancer, although much depends on the age of diagnosis – a sister diagnosed at age 40 presents a higher risk than your mother diagnosed at age 75.
Inherited Genetic Mutations. The vast majority of breast cancers (90-95%) occur in women with no family history. However, women with inherited genetic abnormalities in BRCA1 or BRCA2 (Breast Cancer gene 1 and gene 2) have an up to 85% risk of developing breast cancer by age 70. Individuals of Ashkenazi Jewish descent are more likely to have this genetic mutation, but in the general population the rate is less than 1%.
Ethnic Background. Caucasian women have a higher incidence of breast cancer than Hispanic/Latino, Asian or African American women. But, in women under 40 years, African Americans have the highest rate of breast cancer incidence, and also a higher mortality rate.
High Breast Tissue Density/Breast Changes. High breast tissue density has been shown to be a strong independent risk factor in the development of breast cancer. Certain changes to breast tissue are associated with increased risk of breast cancer.
Radiation Therapy Before 30 Years. High-dose radiation to the chest, especially before age 30, is associated with higher breast cancer risk.
Menopausal Hormone Therapy (MHT). Many women discontinued the use of MHT after results published in 1992 from the Women’s Health Initiative study showed an increased risk of developing breast cancer in women taking MHT. Higher risk is associated with longer use. MHT is no longer recommended for osteoporosis as newer drugs like Fosamax, Evista, and Boniva prevent bone loss without the increased breast cancer risk (note, these drugs aren’t without their problems; they have a different set of side-effects and risks).
The Good News?
Fortunately, there are many ways to make the kind of dietary and lifestyle changes that can help mitigate your risk not only for breast cancer, but numerous other cancers as well as heart disease and chronic inflammatory conditions.
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