Key clinical point: In patients with ductal carcinoma in situ (DCIS), tumor bed boost after postoperative whole breast irradiation (WBI) reduced local recurrence but with higher toxicity. Hypofractionated WBI was as effective as conventional WBI.
Major finding: The 5-year free-from-local-recurrence rates improved significantly with vs without tumor bed boost after postoperative WBI (hazard ratio 0.47; P < .001) and did not worsen with hypofractionated vs conventional WBI ( P = .85). The rates of grade ≥2 breast pain ( P = .003) and induration ( P < .001) were higher with vs without tumor bed boost.
Study details : Findings are from a multicenter, phase 3 study including 1608 adult women with unilateral, non-low-risk DCIS who underwent breast-conserving surgery and were randomly assigned to receive WBI (conventional or hypofractionated) with or without tumor bed boost.
Disclosures: This study was funded by the National Health and Medical Research Council of Australia and other sources. Some authors declared receiving research grants, funding, or non-direct financial support from several sources.
Source: Chua BH et al. 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 Lancet. 2022;400(10350):431-440 (Aug 6). Doi: 10.1016/S0140-6736(22)01246-6