Where we’ve come.

Here is a fascinating narrative account of how gradual hypofractionation studies have now solidly arrived at 5 fractions as the standard of care for whole breast radiation. First, how did we land on 1.8 Gy per day for so long? It was all born from the standard daily X-ray exposure of 200 roentgen (i.e. 1.8 Gy) used by Marie Curie herself…in the 1920s. Well, it’s the 2020s now, and we’ve just recently seen a major shift. Despite 40 Gy / 15 being first pioneered in the UK in the 1940s during wartime shortages, it wasn’t adopted as the standard there until the START trials conducted in the turn of the century; of note, this includes post-mastectomy cases and/or inclusion of level 1–4 axilla. A critical observation from these trials, which demonstrated both lower rates of local recurrence and of normal tissue effects, was that reducing the overall treatment time appears to positively impact tumor control to a degree that overcomes the slight decrease in equivalent dose at 2 Gy per fraction. This trend was again observed in the FAST Forward trial that reduced overall treatment time to 5 days with a regimen of 26 Gy / 5, the current standard for whole-breast, partial-breast and chest wall radiation in the UK since its publication in 2020.  Ongoing international trials are assessing these regimens for comprehensive nodal irradiation and simultaneous integrated boosts to all be completed in a total of five days. | Yarnold, Clin Oncol 2022