Wednesday, February 08, 2023 CCTG MA33 primary publication: Radiation doses and fractionation schedules in non-low-risk ductal carcinoma in situ in the breast Chua BH, Link EK, Kunkler IH, Whelan TJ, Westenberg AH, Gruber G, Bryant G, Ahern V, Purohit K, Graham PH, Akra M, McArdle O, O'Brien P, Harvey JA, Kirkove C, Maduro JH, Campbell ID, Delaney GP, Martin JD, Vu TT, Muanza TM, Neal A, Olivotto IA. Radiation doses and fractionation schedules in non-low-risk ductal carcinoma in situ in the breast (BIG 3-07/TROG 07.01): a randomised, factorial, multicentre, open-label, phase 3 study. The Lancet 400: 431-40, 2022. https://www.sciencedirect.com/science/article/pii/S0140673622012466 Researchers explored whether the addition of tumour bed boost after breast-conserving surgery (BSC) in women with non-low risk ductal carcinoma in situ in the breast (DCIS) reduces the risk of local recurrence (invasive or intraductal recurrence in the ipsilateral breast). Also whether the risk of local recurrence in the shorter fractionation arm is not worse than that for the standard fractionation arm. This would improve the outcome of women with non-low risk DCIS treated with breast conserving therapy and allow for individualizes treatment selection for women with DCIS to achieve long term disease control with minimal toxicity. For more information please visit the MA33 trials page.