TARGIT: an international trial of intraoperative versus external beam radiotherapy

Background

Over the past 30 years, there has been a dramatic change in the local management of breast cancer, with radical operations being replaced by more conservative surgical procedures, together with the widespread use of radiotherapy. This shift has been prompted by results from randomised clinical trials that have clearly demonstrated breast-conserving surgery followed by radiotherapy is equivalent to more radical procedures in terms of local control and overall survival [1]. However, although the surgery is now conservative, the radiotherapy remains radical and may be overtreatment. Evidence for this comes from large studies of breast-conserving therapy where more than 90% of early breast recurrences were found to occur at the site of the original primary tumour site, whether or not radiotherapy was given and/or the margins were involved [2, 3]. The development of a novel radiotherapy device enabled the launch of an international randomised controlled trial designed to compare intraoperative versus conventional external beam radiotherapy in women with early breast cancer [4].

Methods

Intrabeam^® (Carl Zeiss, Germany) is a miniature electron beam-driven X-ray source that provides low-energy X-rays directly into the area of interest immediately after excision of the tumour, to provide intraoperative radiotherapy accurately targeted to the tissues with the highest risk of local recurrence. Following treatment delivery in the operating theatre, women can then proceed to have chemotherapy and/or adjuvant hormonal therapy as required. An equivalence trial, the main outcome objective is risk of local relapse within the treated breast. Secondary objectives are to compare the treatment arms with respect to the site of relapse within the breast; relapse-free survival and overall survival; and local toxicity/morbidity.

Results

With centres in eight countries, TARGIT is nearly halfway to the accrual goal of 2,232 patients. Follow-up information is gathered through a web-based data entry system. Separate protocols are being written to address cosmetic outcome; patient satisfaction and quality of life; health economics and cost-benefit; and patient preference.

Conclusion

This technique could have enormous implications for both cost and availability of breast cancer treatment. TARGIT is currently open to accrual of patients and centres. For further details please visit http://www.targittrial.org