Most breast cancers will be diagnosed from routine breast imaging. The goal of routine screening is to detect a breast cancer when it is so small that it does not yet cause symptoms. Routine screening on a regular basis allows for detection of microscopic lesions that are extremely treatable. The current recommendations include annual or biannual screening mammogram for women at average risk of breast cancer development. For women with dense breasts, 3D tomosynthesis mammogram and/or screening breast ultrasound should be considered. For women who are at increased or high risk, your physician may recommend additional screening with a breast MRI as well (see Breast Imaging).
Although most breast cancers are found on routine screening, breast cancer can present with signs and symptoms:
Lump: A new lump in the breast always warrants further evaluation by a physician. A lump may feel like a well-defined nodule or a vague area of increased density. While many palpable findings may be benign, any new changes or concerns should be brought to your physician’s attention.
Shape: The overall shape of the breast may become different or asymmetric, or a single area may appear to be pulled in or tethered. While it is not uncommon that women have unequal breast sizes, any new differences should be evaluated.
Skin: Any changes in the skin such as redness, thickness, swelling, puckering, dimpling, or indentation should be evaluated.
Nipple: Nipple changes may include flattening or retraction of the nipple or a discharge. While nipple discharge may be benign, any spontaneous discharge that comes from one breast or is bloody or clear, should be evaluated. A rash or ulceration of the areolar skin should also be evaluated.
Lymph nodes: Any lump in the armpit should be evaluated by your physician.
Breast cancers are categorized by the type of cell that they originate from. Most breast cancers arise from the ducts of the breast and are referred to as ductal carcinomas. Other breast cancers develop in the lobules, the structures which make milk, and are referred to as lobular carcinomas. Other less common types of breast cancers include metaplastic, mucinous, papillary, tubular, and medullary carcinomas.
Whether a cancer is of ductal or lobular origin, it is staged and treated the same. However, there are some differences that are important. As a group, lobular cancers tend to be a less aggressive than their ductal counterpart and tend to be estrogen positive (see below). However, because of the pattern of spread of lobular cancers in single file, they tend to be more insidious and often are difficult to detect and therefore diagnosed at higher stages than ductal cancers.
In order to determine how to best treat your cancer, your physician will be interested in the unique characteristics of your tumor which are called biomarkers, and which are typically performed on the biopsy specimen.
Estrogen receptor expression: Breast cancers that have estrogen receptors are considered estrogen positive and are fueled by estrogen. In this case, estrogen promotes cancer cell growth and division. This type of tumor responds well to estrogen-blocking medications. Patients who are currently taking hormone replacement medication will be asked to discontinue as soon as the diagnosis is made since the added estrogen can trigger cancer growth. Birth control pills in a menstruating female is less concerning since a patient’s ovaries will still be making estrogen even if the pills are stopped. Ultimately, however, when anti-estrogen medications become a part of the treatment, discontinuation of the hormonal birth control will be discussed.
Progesterone receptor expression: These cancers also have receptors that bind progesterone and are also responsive to hormone blocking therapy.
Her2 receptor over-expression: Breast cancers that are found to overexpress the protein, Her2Neu, are unique and make up approximately 15-20% of all breast cancers. These cancers produce an over-abundance of the Her2 protein, which drives cancer cell growth. Antibody therapies are available that directly target this Her2 pathway and shut down cancer cell growth.
Triple negative tumors: If a cancer does not have estrogen or progesterone expression and does not overexpress the Her2 gene, this type of tumor is considered “triple negative”, i.e. it is negative for the three markers estrogen, progesterone and Her2. The significance of this is that the targeted therapies which are meant to shut down the estrogen and Her2 pathways are not effective for this type of cancer, because this type of cancer does not rely on those elements for cancer cell growth. Therefore, chemotherapy is the mainstay of treatment for this type of cancer.
Ki67: The Ki67 is a marker of proliferation and measures what percentage of your tumor cells are actively dividing. A lower number indicates a less rapidly dividing cancer and is more favorable.
Breast cancer is divided into five stages (0, I, II, III, IV) using the classification system of the American Joint Committee on Cancer (AJCC). This TNM system (tumor, nodes, metastasis) uses information about the tumor size, presence of cancer in lymph nodes, and any evidence of distant metastases to help determine prognosis. More recently, the unique biology of a patient’s cancer has also been included in the staging system as we recognize that the type of breast cancer can be as important as the stage in determining outcome. Non-invasive breast cancer, termed ductal carcinoma in situ, is Stage 0 and is not life-threatening. All stages of breast cancer, except Stage IV, are curable. Stage IV breast cancer is still treatable but not curable with currently available treatment. Many clinical trials are available at UCLA for the treatment of Stage IV breast cancer.
The stage of a breast cancer is different than the grade of a breast cancer. The grade is a characteristic of the tumor itself and can be 1, 2 or 3 (well differentiated or low-grade, moderately differentiated or intermediate-grade, poorly differentiated or high-grade), and reflects the aggressiveness of a tumor.