Top Line: How does cosmesis after 5-fraction whole breast radiation compare to moderate hypofractionation?
The Study: The FAST and FAST-Forward trials have compared 5-fraction whole breast radiation to conventional and moderately hypofractionated whole breast radiation, respectively. They found that 28.5 Gy in 5 weekly fractions or 26 Gy in 5 consecutive daily fractions resulted in non-inferior control and cosmetic outcomes. Here’s another randomized trial of 107 patients with early stage breast cancer who were randomized to receive either 40 Gy in 15 fractions or 25 Gy in 5 daily fractions. The latter was chosen as equivalent to 50 Gy in 25 fractions based on a radiobiological analysis of large randomized trials showing an alpha/beta of 2.88 for breast cancer. In the hypofractionated arm, an optional sequential or simultaneous integrated boost could be used, and in the 5-fraction arm, an optional 30 Gy SIB could be used. No grade 3 toxicity was observed in either arm, and there was no difference in the rate of grade 2 dermatitis. At the end of treatment, there were also no differences in worse cosmesis or the rates of excellent/good cosmesis. At 3 months, the rate of excellent/good cosmesis was worse after 5-fraction treatment (91% v 100%). However, this difference was no longer apparent at 1 year and beyond.
TBL: In this randomized trial, 25 Gy in 5 fractions whole breast radiation resulted in similar cosmetic outcomes compared to 40 Gy in 15 fractions. | Laughlin, Int J Radiat Oncol Biol Phys 2023
The Study: The FAST and FAST-Forward trials have compared 5-fraction whole breast radiation to conventional and moderately hypofractionated whole breast radiation, respectively. They found that 28.5 Gy in 5 weekly fractions or 26 Gy in 5 consecutive daily fractions resulted in non-inferior control and cosmetic outcomes. Here’s another randomized trial of 107 patients with early stage breast cancer who were randomized to receive either 40 Gy in 15 fractions or 25 Gy in 5 daily fractions. The latter was chosen as equivalent to 50 Gy in 25 fractions based on a radiobiological analysis of large randomized trials showing an alpha/beta of 2.88 for breast cancer. In the hypofractionated arm, an optional sequential or simultaneous integrated boost could be used, and in the 5-fraction arm, an optional 30 Gy SIB could be used. No grade 3 toxicity was observed in either arm, and there was no difference in the rate of grade 2 dermatitis. At the end of treatment, there were also no differences in worse cosmesis or the rates of excellent/good cosmesis. At 3 months, the rate of excellent/good cosmesis was worse after 5-fraction treatment (91% v 100%). However, this difference was no longer apparent at 1 year and beyond.
TBL: In this randomized trial, 25 Gy in 5 fractions whole breast radiation resulted in similar cosmetic outcomes compared to 40 Gy in 15 fractions. | Laughlin, Int J Radiat Oncol Biol Phys 2023