Implementation of the three-field electron wraparound technique for extensive recurrent chest wall carcinoma: dosimetric and clinical considerations.

Treatment of extensive recurrent chest wall carcinoma is a challenge for the radiation oncologist as well as the physics team responsible for setup, computer planning, and daily reproducibility. While electron arc therapy is desirable, unfortunately, most sites do not have this capability. The alternative method of treatment discussed here involves the use of a three-field electron wraparound technique for the chest wall when electron arc therapy is not available. This technique yields an excellent alternative treatment modality with flexibility to accommodate multiple electron energies to compensate for varying chest wall thickness. An additional anterior photon beam is used when skin lesions extend superiorly to the clavicle and along the proximal aspect of the arm. Computerized tomography (CT) interfaced radiotherapy computer planning is used to precisely calculate the sequential gantry angles, skin gaps for adjacent electron fields, and the appropriate junction moves to create a feathering effect of all overlap areas. Treatment aids include extensive shaping of electron and photon fields and the application of bolus material on all four fields. A Smithers Medical Products' Alpha Cradle is used to make this intricate setup possible, providing patient comfort and daily reproducibility for a more efficient treatment.