The breasts are paired mammary glands located at the upper, anterior aspect of the chest. If lactating the breast will secrete milk for nourishment of an infant. A malignant neoplasm is a tumor that gains access to tissue and spreads to other areas. A malignant neoplasm of the breast is also referred to as cancer. In this case, the malignant tumors are located in the breast. Breast cancer can begin in different areas of the breast - the ducts, the lobules, or in some cases, the tissue in between. Breast cancer can be non-invasive, invasive, and metastatic breast cancers. Breast cancer occurs mainly in women, but men can get it, too.

Cancer is caused by genetic or chromosomal changes in cells. The direct cause of these changes is unknown. Cancer has been linked to a high-fat dietary intake, obesity, and environmental, chemical, heredity, and immunological factors.

Signs and symptoms may depend on the site of the disease. Signs and symptoms of malignant breast conditions may include: a breast lump; changes in breast symmetry or size; thickening or dimpling of the skin; edema; ulceration; itching; burning; change in skin temperature; erosion; and retraction or discharge from the nipple. Pain may or may not be present.

Physical and breast examinations, mammogram, tissue biopsy, tumor staging, blood studies, ultrasound, x-ray, electrocardiogram (EKG), bone scan, computed tomography (CT) scan, magnetic resonance imaging (MRI), or hormone receptor assay may be indicated.

The surgical procedure will be dictated by the site of the cancer and the its invasiveness. Varying levels of mastectomy may be performed, depending on the stage and degree of the disease. In addition, radiation therapy, chemotherapy, antiestrogen or other hormone therapies, bone marrow transplant, or a combination of these measures may be used to treat the disease. Pain management and nutrition therapy may be initiated.

There is potential for recurrence or metastasis postoperatively which can appear at any time after primary therapy, and may depend on the stage and amount of residual disease as well as the patient's genetic and biologic factors. Development of osteoporosis may occur. Long-term hormone therapy may be indicated. The potential for infection exists. Scarring and skin disfigurement may not resolve. Breasts may be asymmetrical. Social isolation and feelings of altered sexual identity may develop. Counseling, psychotherapy, and support groups may be indicated to assist the patient in dealing with the diagnosis. A hospice program may eventually be needed in advanced stages of the disease.

• Consider service connection on a presumptive basis as a chronic condition (38 CFR 3.307; 3.309(a)).
• Consider service connection on a presumptive basis as a condition associated with ionizing radiation exposure (38 CFR 3.307; 3.309(d); 3.311).

• A rating of 100 percent shall continue beyond the cessation of any surgical, radiation, antineoplastic chemotherapy or other therapeutic procedure. Six months after discontinuance of such treatment, the appropriate disability rating shall be determined by mandatory VA examination. Any change in evaluation based upon that or any subsequent examination shall be subject to the provisions of 38 CFR 3.105(e) . Rate chronic residuals according to impairment of function due to scars, lymphedema, or disfigurement (e.g., limitation of arm, shoulder, and wrist motion, or loss of grip strength, or loss of sensation, or residuals from harvesting of muscles for reconstructive purposes), and/or under diagnostic code 7626.
• Natural menopause, primary amenorrhea, and pregnancy and childbirth are not disabilities for rating purposes. Chronic residuals of medical or surgical complications of pregnancy may be disabilities for rating purposes.
• When evaluating any claim involving loss or loss of use of one or more creative organs or anatomical loss of one or both breasts, refer to 38 CFR 3.350 to determine whether the Veteran may be entitled to special monthly compensation. Footnotes in the schedule indicate conditions which potentially establish entitlement to special monthly compensation; however, almost any condition in 38 CFR 4.116 might, under certain circumstances, establish entitlement to special monthly compensation. 
• May be entitled to special monthly compensation where the veteran has a single service-connected disability rated as 100% with additional service-connected disability or disabilities independently ratable at 60% or more, which are separate and distinct from the 100% service-connected disability and involves different anatomical segments or bodily systems. See  38 CFR 3.350(i)(1) – Special Monthly Compensation (SMC).