Trial Information

WILL MULTIFUNCTIONAL MAGNETIC RESONANCE TECHNIQUES, DETAILED HISTOPATHOLOGICAL ANALYSIS AND PRONE TREATMENT POSITION IMPROVE ACCURACY OF TARGET VOLUME LOCALISATION & DEFINITION AND REDUCE EXPOSURE OF NORMAL TISSUES IN BREAST RADIOTHERAPY?

OBJECTIVES:

- To improve precision of tumor bed localization and definition of clinical target
volume, and to reduce normal tissue irradiation in women undergoing partial breast or
breast boost radiotherapy.

- To test whether post-operative MRI improves the precision of tumor bed delineation
after wide-local excision in comparison with the current standard CT scan/clip method.

- To determine the impact of tumor position within the excision specimen upon the
localization of clinical target volume in relation to the tumor bed.

- To compare theoretical non-target tissue exposure from partial breast irradiation
planned in the supine and prone (face-down) positions.

OUTLINE: Patients undergo planned breast-conservation surgery and placement of titanium
clips to the four radial, the deep, and superficial margins of the excision cavity (for
localization of tumor bed).

Within 2 weeks after surgery, patients undergo supine radiotherapy-planning CT scan as
standard analysis. Patients then undergo a radiotherapy-planning CT scan in the prone
position. Patients complete a linear analogue questionnaire after both scans designed to
assess patient comfort and anxiety in each position. Patients then undergo multifunctional
MRI (including dynamic contrast-enhancement MRI and diffusion-weighted MRI) of the
ipsilateral breast in the prone position (≥ 3 weeks after surgery). If suspicious lesions ≥
5 mm are found on MRI, patients are referred for a second-look ultrasound with biopsy (if
lesion visible on ultrasound); where suspicious lesions are seen only on MRI, patients
undergo MRI-guided biopsy. Lesions < 5 mm are included in the whole-breast radiotherapy
treatment.