The prone technique for breast irradiation - is it ready for clinical trials?

Our aim was to determine whether a radiotherapy technique for treating breast cancer patients in a prone position could be developed as a means of reducing toxicity. We also aimed to consider its suitability for testing in a large randomized study.

Based on the sparse literature and techniques currently used at other centres, we designed a simple technique for simulation and treatment in the prone position. A specialised patient positioning device was designed to allow the breast to hang vertically downwards away from the chest wall and away from the contralateral breast. Planning and treatment were performed, and clinical data on the first 40 patients treated were reviewed.

The reasons given by clinicians for choosing the prone technique included a large, pendulous breast shape (36 patients), an elevated risk of pneumonitis (three patients) and inability to adopt a supine position due to arthritis (one patient). The treatment was well tolerated, although 50% of the patients still developed moist desquamation. All but one patient completed their full course of radiotherapy. Dosimetric analysis revealed high levels of dose homogeneity and low doses to surrounding normal structures. With a median follow-up of 11 months, only one patient has developed metastatic disease, and one has locally recurred.

This study shows that prone breast irradiation for patients with large or pendulous breasts can be readily developed in radiotherapy treatment centers and could be tested for efficacy in a large, multi-centre randomized trial.