Primary invasive breast cancer

Breast cancer is a malignancy that is often strongly influenced by age, family history, genetic factors, hormonal exposure, and lifestyle factors.

On physical exam, the patient usually demonstrates a firm breast mass, which may be associated with axillary lymphadenopathy, skin changes, and nipple discharge.

Asymptomatic patients may be diagnosed with breast cancer after abnormal calcifications and/or architectural distortion are noted on a routine screening mammogram.

Treatment requires a multidisciplinary approach, involving medical oncologists, breast surgeons, and radiation oncologists.

Complications of therapy are specific to each modality of treatment, and careful monitoring and preventive therapy for adverse events (e.g., antiemetic pre-medications in the prevention of nausea) are essential.

Primary invasive breast cancer is a malignancy originating in the breast(s) and nodal basins. The term "invasive" indicates that the malignancy has penetrated past the basement membrane of the duct or lobule of the breast and has spread to the surrounding tissues, but has not spread to other organs.

The American Joint Committee on Cancer TNM (tumor, node, metastasis) staging system classifies invasive breast cancer into the following stages based on the extent of disease: IA, IB, IIA, IIB, IIIA, IIIB, and IIIC.[1]Amin MB, Edge S, Greene, F, et al, eds. AJCC cancer staging manual. 8th ed. New York: Springer; 2017. http://cancerstaging.org/references-tools/deskreferences/Pages/default.aspx Stages IA, IB, and IIA are generally considered early-stage breast cancer. Stages IIIA, IIIB, and IIIC are generally considered locally advanced breast cancer. Stage IIB can be considered early-stage breast cancer if the tumor is >20 mm but ≤50 mm and has spread to 1 to 3 axillary lymph nodes (i.e., T2 N1 M0), or locally advanced breast cancer if the tumor is >50 mm with no axillary lymph nodal involvement (i.e., T3 N0 M0).