As reported in the Journal of Clinical Oncology by Vicini et al, the phase III NRG/RTOG 1005 trial has shown noninferior risk for ipsilateral breast recurrence (IBR) with concurrent vs sequential radiation dose escalation to the surgical cavity in conservative treatment of high-risk early breast cancer.
Study Details
In the open-label multicenter trial, 2,255 eligible patients at higher risk for IBR after lumpectomy and axillary surgery were randomly assigned between May 2011 and June 2014 to receive: a sequential boost of 12 Gy in 6 fractions or 14 Gy in 7 fractions after whole breast irradiation (WBI) of 50 Gy in 25 fractions or 42.7 Gy in 16 fractions (sequential group, n = 1,118); or a concurrent boost of 8 Gy in 15 fractions of 0.53 Gy per day with WBI of 40 Gy in 15 fractions (concurrent group, n = 1,137) using three-dimensional conformal radiation therapy or intensity-modulated radiation therapy.
Key Findings
Over a median follow-up of 7.3 years, there were 56 IBR events; 5- and 7-year IBR rates were 2.1% and 2.2% in the sequential group vs 1.9% and 2.6% in the concurrent group, meeting the noninferiority criterion (hazard ratio = 1.31, 95% confidence interval [CI] = 0.84–2.04), P = .037 for noninferiority.
No significant differences between the sequential group vs the concurrent group were observed in 5-year overall survival (95.6% vs 95.1%) or 7-year overall survival (93.5% vs 93.6%).
Among all patients, treatment-related adverse events of grade 2 or higher were infrequent. No difference in treatment-related grade 3 to 4 events was observed between groups (P = .81).
No significant differences between the sequential group vs the concurrent group for excellent/good cosmesis by physician rating were observed at baseline (96.0% vs 94.9%, P = .61) or at 3 years (85.9% vs 82.4%, P = .34).
The investigators concluded: “Concurrent boost during WBI results in noninferior IBR compared with sequential boost without worsening toxicity or cosmetic outcomes and reduces overall treatment time.”
Frank Vicini, MD, FACR, FASTRO, FABS, of Michigan Healthcare Professionals Farmington, Farmington Hills, Michigan, is the corresponding author for the Journal of Clinical Oncology article.
DISCLOSURE: The study was supported by grants from the National Cancer Institute. For full disclosures of the study authors, visit ascopubs.org.
