Postoperative intensity-modulated radiation therapy for head and neck cancers: A case-based review

Postoperative radiation therapy targets of the head and neck region are often adjacent to nearby critical and avoidance structures. Therefore, intensity-modulated radiation therapy (IMRT) is preferred over previous techniques primarily due to (1) the ability to conform the high-dose regions around geometrically complex targets, (2) the ability to build steep dose gradients between targets and nearby critical structures, and (3) the ability to generate relative sparing of various surrounding nontarget normal structures from clinically significant doses without compromise of desired target coverage. Compared to clinical target volume delineation of intact regions (i.e., unoperated or unviolated neck), postoperative clinical target volumes are generally broader, in that they cross adjacent disturbed anatomic boundaries, are inclusive of surgical tracts and suture lines, and come nearer to the patient surface. Here we provide an expanded case-based illustration of our current approach to postoperative IMRT target volume delineation and treatment planning for various disease sites within the head and neck.