Abstract
ObjectiveTo 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.DesignProspective, open label, randomised controlled clinical trial.Setting32 centres in 10 countries in the United Kingdom, Europe, Australia, the United States, and Canada.Participants2298 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).InterventionsRandom 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 measuresNon-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.ResultsBetween 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 v 11/1158) but 14 fewer deaths (42/1140 v 56/1158) for TARGIT-IORT compared with EBRT. With long term follow-up (median 8.6 years, maximum 18.90 years, interquartile range 7.0-10.6) no statistically significant difference was found for local recurrence-free survival (hazard ratio 1.13, 95% confidence interval 0.91 to 1.41, P=0.28), mastectomy-free survival (0.96, 0.78 to 1.19, P=0.82), distant disease-free survival (0.88, 0.69 to 1.12, P=0.30), overall survival (0.82, 0.63 to 1.05, P=0.13), and breast cancer mortality (1.12, 0.63 to 1.28, P=0.54). Mortality from other causes was significantly lower (0.59, 0.40 to 0.86, P=0.005).ConclusionFor 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.Trial registrationISRCTN34086741, NCT00983684.
Highlights
In 2018, two million patients were diagnosed as having breast cancer worldwide and 626 000 patients died from the disease.1 Treatment with breast conserving surgery and adjuvant radiotherapy rather than total mastectomy is suitable for most patients
For patients with early breast cancer who met our trial selection criteria, risk adapted immediate single dose Targeted Intraoperative Radiothearpy (TARGIT)-intraoperative radiotherapy (IORT) during lumpectomy was an effective alternative to external beam radiotherapy (EBRT), with comparable long term efficacy for cancer control and lower non-breast cancer mortality
Based on the hypothesis that adjuvant radiotherapy for women with early breast cancer could be limited to the tumour bed and given immediately during breast conserving surgery, we developed the concept of targeted intraoperative radiotherapy (TARGIT-IORT)
Summary
In 2018, two million patients were diagnosed as having breast cancer worldwide and 626 000 patients died from the disease. Treatment with breast conserving surgery and adjuvant radiotherapy rather than total mastectomy is suitable for most patients. Treatment with breast conserving surgery and adjuvant radiotherapy rather than total mastectomy is suitable for most patients. Most local recurrences occur close to the primary tumour site despite the frequent presence of microscopic cancer foci in other quadrants. . Based on the hypothesis that adjuvant radiotherapy for women with early breast cancer could be limited to the tumour bed and given immediately during breast conserving surgery (lumpectomy), we developed the concept of targeted intraoperative radiotherapy (TARGIT-IORT).. When the TARGIT-A trial protocol was published in 1999,8 restricting radiotherapy to only the area around the tumour had been explored in small patient series and one randomised trial, which had reported inferior results. At that time whole breast radiotherapy was the standard of care, and it remains so today, despite the publication of our initial results and several other approaches.
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