Breast Cancer: An Introduction
Women in the United States get breast cancer more than any other type of cancer, except for
skin cancer. Each year, more than 200,000 American women learn they have breast cancer and over 40,000 women die.
Breast cancer is second only to
lung cancer as a cause of cancer death in women. Breast cancer occurs in men also, but the number of cases is smaller
(see Male Breast Cancer).
Cancer is a group of more than 100 different diseases. Cancer occurs when, for unknown reasons, cells become abnormal and divide without control or order. All parts of the body are made up of cells that normally divide to produce more cells, but only when the body needs them. When cancer occurs, cells keep dividing even when new cells are not needed.
The change from normal to cancerous cells requires several separate, different gene alterations. Eventually, altered genes and uncontrolled growth may produce a tumor that can be benign (not cancerous) or malignant (cancerous). Malignant tumors can invade, damage, and destroy nearby tissues and spread to other parts of the body. A benign tumor won't spread to other parts of the body, but local tissue may be damaged and the growth may need to be removed.
Cancer cells can also break away from a malignant tumor and enter the bloodstream or the lymphatic system. This is how cancer spreads within the body. When breast cancer spreads outside the breast, cancer cells often are found in the lymph nodes under the arm. They can also spread to other lymph nodes, the bones, liver, or lungs. (Although it is not common, some patients whose underarm lymph nodes are clear of breast cancer may still have cancer cells that have spread to other parts of the body.)
Cancer that spreads to other parts of the body is the same disease and has the same name as the original cancer. When breast cancer spreads, it is called metastatic breast cancer even though it is found in another part of the body. For example, breast cancer that has spread to the bones is called metastatic breast cancer, not
bone cancer.
Understanding the Breasts
The breasts sit on the chest muscles that cover the ribs. The breast is made up of lobes and ducts. Each breast has 15 to 20 sections called lobes, which have many smaller sections called lobules. Lobules end in dozens of tiny bulbs that can produce milk. The lobes, lobules, and bulbs are linked by thin tubes called ducts. Milk flows from the lobules through these ducts to the nipple. The nipple is in the center of a dark area of skin called the areola. Fat fills the spaces between the lobules and ducts.
Each breast also contains blood vessels and lymph vessels. The lymph vessels carry an almost colorless fluid called lymph. Lymph vessels lead to organs called lymph nodes. In breast cancer, the cancer cells can spread outside the breast into the lymph nodes under the arm. In many cases, if the cancer has reached the lymph nodes, cancer cells may have also spread to other parts of the body via the lymphatic system or through the bloodstream.
Breast cancer types can be invasive (moves into the surrounding tissue) or non-invasive (stays in the ducts or lobes). Invasive breast cancers make up 70 to 80 percent of all breast cancer cases. The most common type of invasive breast cancer is infiltrating ductal carcinoma (also called invasive ductal carcinoma). This
breast cancer type is found in approximately 60 percent of breast cancer cases.
Most
breast cancer causes are not known. In 5 to 10 percent of breast cancer cases, there is a hereditary component.
Risk Factors for Breast Cancer
- Older age
- Early menarche (menstruation)
- Older age at first birth or never having given birth
- A personal history of breast cancer or benign (non-cancerous) breast disease
- A mother or sister with breast cancer
- Treatment with radiation therapy to the breast/chest
- Breast tissue that is dense on a mammogram
- Hormone use (such as estrogen and progesterone)
- Excessive drinking of alcoholic beverages
- Being Caucasian.
Symptoms of Breast Cancer
Not everyone with breast cancer will have early symptoms of the disease. That is why breast cancer screening is so important. Breast cancer screening before there are
symptoms of breast cancer can help doctors find and treat cancer early. Also,
breast cancer treatment is more likely to work well when cancer is found early.
If a woman has possible symptoms of breast cancer, the healthcare provider will ask a number of questions and perform a physical exam looking for other
signs of breast cancer. He or she may also recommend certain tests or procedures including:
- Mammogram
- Ultrasound
- MRI
- Biopsy
- Fine-needle aspiration.
Breast cancer is a complex disease. All breast cancer cases are not the same. Once breast cancer has been found, more tests will be done to find out the specific pattern of breast cancer. This important step is called staging. Knowing the exact breast cancer stage will help your doctor plan your
breast cancer treatment.
Your doctor will want to know:
- The size of the tumor and exactly where it is in your breast
- If the cancer has spread within your breast
- If cancer is present in your lymph nodes under your arm
- If cancer is present in other parts of your body.
- Stage 0 (including lobular carcinoma in situ and ductal carcinoma in situ)
- Stage I
- Stage II (including IIA and IIB)
- Stage III (including IIIA, IIIB, and IIIC)
- Stage IV
- Recurrent.
Women with breast cancer have many treatment options available to them. These breast cancer treatments include:
Many women receive more than one type of treatment for breast cancer, and the choice of breast cancer treatment depends mainly on the stage of breast cancer
(see Breast Cancer Treatment by Stage).
Some of these treatments are considered primary, where the purpose is to remove the tumor. Others are considered adjuvant therapy, which is treatment given to kill any tumor cells that may have spread and increase the chances for a breast cancer cure (
see Adjuvant Therapy for Breast Cancer).
Your doctor can describe your breast cancer treatment choices and the expected results. Then you and your doctor can work together to develop a breast cancer treatment plan that reflects your medical needs and personal values.
Prognosis for Breast Cancer
Most women who are treated for early breast cancer go on to live healthy, active lives. You may have more choices of
breast cancer treatment if your breast cancer is found early.
Breast cancer treatments have changed over time. Today, many women who are diagnosed with breast cancer do not have to lose a breast. Because there are improved ways to treat breast cancer, it is more important than ever for you to learn all you can. Working with your team of medical specialists, you can play a key role in choosing the treatment that is best for you.
Risk Factors for Recurrence of Breast Cancer
Your chance of surviving breast cancer will also depend upon your risk for return of cancer after treatment for breast cancer is completed. Some women are at a higher risk for the spread or return of breast cancer. In many cases, doctors can't explain why one patient stays well and another does not.
Remember, the risk factors for recurrence are complex. They are not absolute predictions of your future health. Some factors that affect the spread or the recurrence of breast cancer are:
- Tumor size: The smaller your tumor, the lower the risk
- Lymph nodes: The fewer underarm lymph nodes that have cancer, the lower your risk
- Cell growth: Cancer cells that grow slowly are linked to a lower risk
- Hormones: If a tumor depends on hormones for growth, hormonal therapy can lower the risk of the cancer spreading or recurring.
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