Breast cancer (BC) is now the most commonly diagnosed cancer in women. Worldwide, an estimated 1.67 million BC cases were diagnosed in 2012, and among men and women combined, BC is now the second most commonly diagnosed cancer after lung cancer (1.82 million cases).

It is of paramount importance to be able to provide good treatment quality to women with BC. A population-based comparison of women diagnosed between 1996 and 1998 found 5-year survival rates of 81% in Europe and 84% in the United States.3 The 5-year relative survival of female patients with BC in the United States has increased steadily from 75.2% in 1975, 78.4% in 1985, 86.8% in 1995, and 90.6% in 2008.4 Improvements in BC treatments have been instrumental in achieving this progress, and adjuvant radiation therapy is an important modality in many BC treatment regimens.