The impact of age on outcome in early-stage breast cancer.

Multiple studies have shown that breast-conserving therapy (BCT) and mastectomy have equivalent outcomes for large populations of women with early-stage breast cancer. For individual treatment decisions, however, it is important to appreciate the heterogeneity of disease. Recent molecular studies have suggested that "breast cancer" includes biologically distinct classes of disease; although these molecular distinctions are important, other patient-related factors also affect outcome and influence prognosis. One of the most important of these patient factors is the age of the patient at diagnosis. Numerous studies have shown very different breast cancer outcomes based on patient age; younger women typically have more aggressive tumors that are more likely to recur both locoregionally and distantly, and older women more commonly have less aggressive disease. The overall disease-specific outcomes, techniques, and doses for adjuvant radiation therapy and toxicity of treatments should be discussed within the context of age because breast cancer is a very different disease based on this factor. Arguments can be made that more aggressive locoregional therapy is warranted in populations of young women with breast cancer and perhaps less aggressive therapy in the elderly.