Cancer that develops in the cells of the breast is called breast cancer. This can occur as a result of DNA damage in the cells. The DNA is what tells your cells to develop and reproduce normally, but if the DNA is damaged, the cells begin to behave differently. Abnormal growth of mutated cells can lead to formation of a tumor, which may be benign (noncancerous) or malignant (cancerous).
Breast cancer is primarily found in women, but the disease can also affect men, generally later in life between the ages of 60 and 70 years old.
Your risk may be higher depending on:
- Your age (increasing age increases your lifetime risk)
- Your family history (having a mother, daughter, sister with breast cancer)
- Early puberty or late menopause (getting your period younger than 12 or entering menopause after age 55)
Types of breast cancer and how it develops
Breast cancer may originate in the lobules, the glands where milk is produced, or in the milk ducts that carry milk to the nipple. Lobular carcinoma in situ (LCIS) is located only in the lobules and is technically not cancer, though it may be a precursor to invasive cancer in the future. Ductal carcinoma in situ (DCIS) may be noninvasive and contained in the milk ducts, or it may be invasive to the surrounding tissue.
If breast cancer cells are found in the lymph nodes, the cancer can quickly spread to other parts of the body (metastasize) and become more difficult to treat.
Within breast cancer there are different subtypes. Your subtype is based on your cancer's unique "receptors." For example, estrogen, progesterone, and HER2 are cancer receptors that stimulate cancer growth. Cancer cells can feed off of the hormones estrogen and progesterone, for example, and tumor growth can be fueled by a particular protein found in the HER2 gene (HER2-positive breast cancer). In some cases, there are no estrogen or progesterone receptors, and there is not an excess of the HER2 protein on the cancer cell surfaces. This is called triple negative breast cancer, an invasive type that grows and spreads quickly.
Testing for these receptors can help your doctor determine the best treatment approach for you.
Breast cancer exams and screening help diagnose disease
Initial diagnosis of breast cancer often occurs during your own breast self-exam, during a breast exam at your annual OB/GYN visit, or during a routine mammogram. If your doctor suspects something abnormal, he or she will likely prescribe additional testing, that may include a biopsy, blood testing, and in some cases, an MRI if other screenings have been inconclusive.
While an abnormal test result can bring up feelings of fear and concern, in many cases the outcome is not breast cancer. If you are diagnosed with breast cancer there are many treatment approaches and therapies available to you—and many people do survive this disease.
At Main Line Health our interdisciplinary team of oncology experts, from surgical oncologists and geneticists to nutritionists and therapists, has vast experience in screening for, diagnosing, and treating breast cancer.