Long Term Survival and Local Control Outcomes from Single Dose Targeted Intraoperative Radiotherapy During Lumpectomy (TARGIT-IORT) for Early Breast Cancer: TARGIT-A Randomised Clinical Trial
OBJECTIVE: To determine whether risk adapted intraoperative radiotherapy, delivered as a single dose during lumpectomy, can effectively replace postoperative whole breast external beam radiotherapy for early breast cancer.
DESIGN: Prospective, open label, randomised controlled clinical trial.
SETTING: 32 centres in 10 countries in the United Kingdom, Europe, Australia, the United States, and Canada.
PARTICIPANTS: 2298 women aged 45 years and older with invasive ductal carcinoma up to 3.5 cm in size, cN0-N1, eligible for breast conservation and randomised before lumpectomy (1:1 ratio, blocks stratified by centre) to either risk adapted targeted intraoperative radiotherapy (TARGIT-IORT) or external beam radiotherapy (EBRT).
INTERVENTIONS: Random allocation was to the EBRT arm, which consisted of a standard daily fractionated course (three to six weeks) of whole breast radiotherapy, or the TARGIT-IORT arm. TARGIT-IORT was given immediately after lumpectomy under the same anaesthetic and was the only radiotherapy for most patients (around 80%). TARGIT-IORT was supplemented by EBRT when postoperative histopathology found unsuspected higher risk factors (around 20% of patients).
MAIN OUTCOME MEASURES: Non-inferiority with a margin of 2.5% for the absolute difference between the five year local recurrence rates of the two arms, and long term survival outcomes.
RESULTS: Between 24 March 2000 and 25 June 2012, 1140 patients were randomised to TARGIT-IORT and 1158 to EBRT. TARGIT-IORT was non-inferior to EBRT: the local recurrence risk at five year complete follow-up was 2.11% for TARGIT-IORT compared with 0.95% for EBRT (difference 1.16%, 90% confidence interval 0.32 to 1.99). In the first five years, 13 additional local recurrences were reported (24/1140
CONCLUSION: For patients with early breast cancer who met our trial selection criteria, risk adapted immediate single dose TARGIT-IORT during lumpectomy was an effective alternative to EBRT, with comparable long term efficacy for cancer control and lower non-breast cancer mortality. TARGIT-IORT should be discussed with eligible patients when breast conserving surgery is planned.
Vaidya, J. S., Kelemen, P. R., & Tobias, J. S. (2020). Long Term Survival and Local Control Outcomes from Single Dose Targeted Intraoperative Radiotherapy During Lumpectomy (TARGIT-IORT) for Early Breast Cancer: TARGIT-A Randomised Clinical Trial. BMJ (Clinical research ed.), 370, 2836-2836. https://doi.org/10.1136/bmj.m2836