Phase III randomised trialDoes an integrated boost increase acute toxicity in prone hypofractionated breast irradiation? A randomized controlled trial

Background and purposeThe safety of a simultaneous integrated boost (SIB) in combination with prone hypofractionated whole-breast irradiation (WBI) was investigated.Materials and methods167 patients were randomized between WBI with a sequential boost (SeB) or SIB. All patients were treated in prone position to 40.05 Gy in 15 fractions to the whole breast. In the control arm, a SeB of 10 Gy in 4 fractions (negative surgical margins) or 14.88 Gy in 6 fractions (transsection) was prescribed. In the experimental arm a SIB of 46.8 or 49.95 Gy (negative and positive surgical margins, respectively) was prescribed.ResultsPatient age was the only significantly different parameter between treatment arms with patients in the SIB arm being slightly older. In both arms, 6/83 patients developed moist desquamation. Grade 2/3 dermatitis was significantly more frequent in the SeB arm (38/83 vs 24/83 patients, p = 0.037). In the SIB and SeB arm, respectively, 36 patients (43%) and 51 patients (61%) developed pruritus (p = 0.015). The incidence of oedema was lower in the SIB arm (59 vs 68 patients), but not statistically significant (p = 0.071).ConclusionsThe primary endpoint, moist desquamation, was not significantly different between treatment arms.