Neck Dissection Planning Based on Postchemoradiation Computed Tomography in Patients With Head and Neck Cancer

Abstract

To determine what findings on postchemoradiation (post-CRT) neck computed tomography (CT) may predict removal of the internal jugular vein (IJV) or sternocleidomastoid muscle (SCM) and to examine whether pretreatment CT had any bearing on the ultimate posttreatment neck dissection with regard to the IJV and SCM. Retrospective review of CT, intraoperative, and pathologic findings. Tertiary care academic medical center. Thirty-four patients who underwent 43 planned post-CRT hemi-neck dissections for pretreatment N2 or greater disease. Of the 43 neck dissections, 39 (91%) were selective neck dissections, 2 (5%) were modified radical dissections, and 2 (5%) were radical neck dissections. The IJV was removed in 6 of the 39 selective neck dissections (15%), in 1 of the 2 modified radical dissections, and in both of the 2 radical neck dissections. The SCM was removed in the 2 modified radical dissections and 2 radical neck dissections. The IJV was removed in 7 of the 9 dissections (78%) in which the IJV was abnormal on preoperative CT (filling defect or thrombosed) vs 2 of the 34 dissections (6%) with a normal IJV on CT (P < .001; positive predictive value, 78%; negative predictive value, 94%). The SCM was removed in 4 of the 11 dissections (36%) in which the tissue plane between the carotid sheath and the SCM was indistinct on CT vs 0 of the 32 dissections with a radiographically normal SCM tissue plane (P = .003; positive predictive value, 36%; negative predictive value, 100%). In 27 patients with pre-CRT CTs for comparison, the IJV normalized in 3 of the 8 patients (38%) with an abnormal IJV on pre-CRT CT, and the tissue plane around the SCM normalized in 15 of the 24 patients (63%) with an indistinct tissue plane on pre-CRT CT. Filling defects or thrombosis of the IJV is highly predictive of need for removal intraoperatively, which may affect planning especially in bilateral neck dissections in which an effort may be made to preserve at least 1 vein. Presence of a clear tissue plane between the SCM and carotid sheath predicts the ability to preserve this muscle. Changes in the status of the IJV and SCM seen on CT that occur as a result of CRT may make preservation of these structures more feasible, even in patients with advanced neck disease.