Abstract

More than 10 years ago, two pivotal trials, the Ontario Clinical Oncology Group trial and START B trial, firmly established that hypofractionated radiation therapy (RT) of 40–42.5 Gy in 15–16 fractions over 3 weeks after breast conserving surgery or mastectomy results in similar rates of local recurrence and normal tissue effects. This led to a new standard for postoperative whole breast and chest wall RT. Further trials confirmed these findings and show that hypofractionated RT can also be applied for other indications, including regional nodal RT and for ductal carcinoma in situ (DCIS). More recently, a so-called ultra-fractionation trial demonstrated that 26 Gy in 5 fractions over 1 week was non-inferior to 40 Gy, in 15 fractions in 3 weeks for local recurrence at 6 years and that late effects were similar between fractionation schedules being a treatment option for most patients with early breast cancer. Several countries and departments are now adopting hypofractionated schedules as a new standard for breast, chest wall or partial breast RT. In addition to the improvement in convenience and reduction in resources required, hypofractionated RT offers important benefits with respect to acute and late toxicity that can improve the quality of life of patients receiving breast RT.