DIBH-IMRT for RTOG 1304, Cancer of the left breast: A case study

The purpose of this case study is to describe an external beam radiation therapy planning technique for carcinoma of the left breast. A female patient on protocol NSABP B-51/RTOG 1304 presented with unusual anatomy and large habitus. Deep inspiration breath-hold (DIBH) IMRT was used in conjunction a DIBH-3D conformal radiotherapy (3DCRT) tangential boost plan to meet the dose criteria for protocol compliance. Traditionally 3DCRT planning using a DIBH technique would be used for both billing authorization and as DIBH-IMRT involves a longer treatment time and more difficulty in terms of patient compliance; however, the patient tolerated the treatment very well. The subsequent treatment plan met all criteria per protocol with the exception of the ipsilateral lung, which passed with acceptable variation.