Breast cancer is the most common cancer in women in the United States and it is estimated that one in eight women will develop breast cancer during their lifetime. However, death rates from breast cancer continue to decrease due to more effective screening and treatment. Early screening improves survival because breast cancer can be treated before it has a chance to spread or form metastases.
Breast cancer forms from cells that have lost control of their normal growth processes. Breast cancer may be diagnosed in a pre-invasive or invasive state. Pre-invasive cancer may be ductal carcinoma in situ (DCIS) or lobular carcinoma in situ (LCIS). DCIS and LCIS behave somewhat differently and your oncology team will recommend different management plans accordingly. DCIS or LCIS seldom spread beyond the breast and do not usually require systemic treatment. These cancers can usually be treated be treated by removal of the area with or without radiation treatment. Rarely, a patient may require a mastectomy.
Invasive ductal cancer is the most common form of invasive breast cancer whereas invasive lobular cancer is less common. Invasive cancers have invaded beyond normal tissue boundaries to gain access to lymph and blood vessels. They can spread to the lymph nodes or to other areas of the body such as the lung, liver or bones. Features of the cancer that influence treatment are the grade (microscopic appearance), the presence of hormone (estrogen and progesterone) receptors, and Her2 expression. These are determined when the biopsy is examined under the microscope using special tests. More than half of breast cancers require estrogen or progesterone to grow, and blocking these hormones be used for treatment. Chemotherapy is often recommended as well. As will all types of cancer, you oncology team will make individualized recommendations that are most appropriate for each patient and tumor.
- Women older than 40 years
- Prolonged estrogen exposure (early menarche <12 years, late menopause > 50 years, late childbirth >30 years)
- Personal history of breast cancer
- A family history of multiple family members with breast cancer
- Male family members with breast cancer
- History of both breast and ovarian cancer in the family
- History of chest wall radiation (commonly for lymphoma) Diagnosis
Breast cancer often does not cause any symptoms but can be diagnosed at an early stage with the use of screening mammograms. A mammogram is an X-ray of the breast and a tumor appears as either an area of calcifications or an abnormal mass. Sometimes, breast cancer can also be picked up on routine breast examination by either the patient or their doctor with one or more of the following:
- A lump in the breast
- Dimpling of the skin
- Retraction of the nipple
- Change in the size or shape of the breast
- New onset of nipple discharge or tenderness
If any of these changes are present, a mammogram or ultrasound of the breast is recommended. This is usually followed by a needle biopsy to determine if breast cancer is present and if so, what type it is. Breast MRI may also be usually to aid in the diagnosis of breast cancer, especially in women at high risk for developing cancer. MRI of the breast is not necessary or helpful in all women – your oncology team will advise you as to the appropriateness of all imaging tests.
If a patient has a mass in their breast, and cancer is suspected, a needle biopsy can be performed in the office. If the tumor cannot be felt, the needle biopsy is guided by either the mammogram (stereotactic breast biopsy) or by ultrasound. A clip may be placed in the breast to mark the site. Sometimes, if the patient is unable to undergo a needle biopsy, a formal surgical biopsy may be necessary.
Prevention and Treatment
The treatment of breast cancer depends on the size, involvement of lymph nodes or spread to other organs (stage). The tumor can spread to the lymph nodes as it gets larger or can spread to other areas of the body.
When the tumor is small relative to the breast size lumpectomy is an option. This is combined with radiation treatment LINK TO RADIATION ONCOLOGY to the breast after healing is complete, to decrease the chance of tumor recurrence. This approach is called breast conservation. For advanced cancers, or those that involve multiple areas of the breast, a complete removal of the breast, called mastectomy, may be required. Some patients may be able to undergo reconstructive surgery at the same time while others may need delayed reconstruction after mastectomy.
One of the first sites of spread of breast cancer is the lymph nodes under the arm. If the cancer has already spread to the lymph nodes, it usually requires removal of all the lymph nodes under the arm. This procedure is called an axillary dissection. An axillary dissection can be associated with some side effects, such as arm swelling or lymphedema. If the lymph nodes appear to be free of cancer, a sentinel node biopsy is performed. This special test is done to identify the lymph node most likely to have cancer cells. This lymph node is removed during surgery and if cancer is present, only then are the remaining nodes removed. This helps to minimize the risk of complications.
For large cancers and those that have already spread to the lymph nodes, a staging work up is done which may include CT scans, bone scans, blood work or PET scans. Further treatment then depends on the stage of the cancer. Drugs to block estrogen and progesterone are recommended for all women with hormone receptor positive cancers greater than 1 cm, while women with hormone receptor negative cancer, those with involvement of the lymph nodes or large sized tumors may benefit from chemotherapy. Radiation therapy is usually when the breast is preserved but may also be used after mastectomy when the tumor was very large or if multiple nodes were involved with cancer.