Breast: Whole-breast hypofractionation
Free question published 19 July 2026
A 58-year-old woman has undergone wide local excision for a 14 mm, grade 2, ER-positive, HER2-negative invasive ductal carcinoma. The sentinel node biopsy was negative (pN0) and resection margins are clear. She is to receive adjuvant whole-breast radiotherapy without regional nodal irradiation, and you are discussing fractionation. Which schedule is the most appropriate standard whole-breast schedule to offer?
- A60 Gy in 30 fractions over 6 weeks
- B40 Gy in 15 fractions over 3 weeks
- C50 Gy in 25 fractions over 5 weeks
- D50 Gy in 25 fractions plus a 16 Gy boost
- E45 Gy in 25 fractions over 5 weeks
Why B is correct
The START B trial showed that 40 Gy in 15 fractions over 3 weeks gives locoregional relapse and late adverse-effect rates at least as favourable as 50 Gy in 25 fractions, and it has been adopted as the standard UK whole-breast schedule. NICE NG101 recommends moderate hypofractionation for whole-breast radiotherapy.
And why the others are not
- AIncorrect. 60 Gy in 30 fractions overtreats the whole breast and is not a standard adjuvant whole-breast schedule.
- CIncorrect. 50 Gy in 25 fractions is the historical conventional schedule that hypofractionation has replaced as standard, with no advantage over 40 Gy in 15 fractions.
- DIncorrect. A tumour-bed boost is reserved for those at high risk of local recurrence; this node-negative grade 2 patient does not warrant a routine boost, and the conventional 50 Gy base is outdated.
- EIncorrect. 45 Gy in 25 fractions is an underdose for whole-breast adjuvant treatment and is not a recognised standard schedule.
Source START B - Hypofractionated whole-breast radiotherapy (40 Gy in 15 fractions) — START Trialists' Group; Bentzen SM, Agrawal RK, et al. The UK Standardisation of Breast Radiotherapy (START) Trial B of radiotherapy hypofractionation for treatment of early breast cancer: a randomised trial. Lancet. 2008;371(9618):1098-1107. 10-year follow-up: Haviland JS, et al. Lancet Oncol. 2013;14(11):1086-1094.
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