A new study will confirm whether an advanced radiotherapy technique that uses imaging of titanium clips implanted during surgery can reduce side-effects from breast cancer treatment.
The study, led by The Institute of Cancer Research and funded by the Efficacy and Mechanism Evaluation (EME) programme, will compare image guided radiotherapy (IGRT) with the standard imaging technique. The study is a collaboration between the ICR, The Royal Marsden NHS Foundation Trust, Addenbrooke's Hospital NHS Trust, Clatterbridge Centre for Oncology, Ipswich Hospital NHS Trust, Torbay Oncology Unit and Royal Preston Hospital.
A course of radiotherapy is often given after surgery to kill any remaining breast cancer cells and reduce the risk of recurrence. Breast cancers usually recur close to the site of the original cancer (the tumour bed) so scientists are investigating options for delivering radiotherapy more precisely to this area, thereby reducing damage to surrounding tissue.
Currently X-rays are used to direct radiotherapy treatment to the critical area however they reveal only the position of surrounding organs and bones and not the exact location of the tumour bed. A safety margin must therefore be added to ensure the tumour bed always falls in the treatment area, with the result that a high dose of radiotherapy has to be given to twice as much healthy breast tissue as would otherwise be necessary.
In the latest study, known as IMPORT-IGRT, patients will have the walls of their surgical excision cavity marked with small titanium clips that can be seen in x-ray images. This will allow the tumour bed to be more precisely located and radiotherapy can be given to a smaller amount of breast tissue.
The study, led by Professor Philip Evans from the ICR, will measure the accuracy of radiotherapy that makes use of IGRT compared with standard imaging. The scientists will evaluate how effective the IGRT technique is in reducing the volume of tissue treated at a high dose, and determine the consequent reductions in risk to normal tissue compared with the standard technique.
'Our pilot studies suggest that safety margins around the tumour bed can be greatly reduced, leading us to expect a lower rate of long-term complications such as breast shrinkage, hardness, pain and rib fracture,' said Professor Evans. 'In this study, we will be able to calculate exactly how much breast tissue we were able to spare and the implications this will have on side-effects.'
The study builds on an ongoing trial called IMPORT-HIGH, which is led by Professor John Yarnold of the ICR and Dr Charlotte Coles of Addenbrooke's Hospital. IMPORT-HIGH is recruiting 840 women across the UK who are at average or above risk of breast cancer coming back, to compare the effectiveness of standard radiotherapy to the whole breast with radiotherapy more precisely targeted to the tumour bed using IGRT. IMPORT-IGRT aims to recruit 250 women from the original IMPORT-HIGH study.
