TARGIT (targeted intra-operative radiotherapy for early stage breast cancer): Results from the TARGIT a randomized controlled trial

Background: After breast conserving surgery, 90% of recurrent cancer occurs within the index quadrant. Hence, restricting radiation therapy to the immediate area around the tumour bed after removal of the primary tumour may be adequate (Vaidya JS et al. Br J Cancer 1996;74:820–4). Materials and methods: Using the technique of partial breast irradiation developed at UCL (Vaidya JS, Baum M, Tobias JS, et al. Ann Oncol 2001;12:1075–80) we launched the international TARGIT A randomized controlled trial in March 2000 comparing the policies of TARGIT versus standard whole breast external beam radiotherapy (EBRT) after breast conserving surgery with local recurrence as the main outcome measure (www.thelancet.com/protocol-reviews/99PRT-47). Accrual from 28 international centers reached 2232 in April 2010, with 80% power to detect a difference in relapse rate of 2.5% (the non-inferiority margin). Results: Patient demographic and tumour characteristics are as follows: mean age 63 years (IQR 57–69), mean tumour size 12mm (IQR 9–18mm), N stage 17% +ve. We intend to present the unblinded data with an analysis of safety and efficacy. Conclusions: If this analysis shows non-inferiority, then a clinically significant difference in early local recurrence between TARGIT and EBRT remains unlikely, making single session partial breast irradiation with TARGIT a plausible new standard of care in the near future.