Lymph node-positive head and neck cancer treated with definitive radiotherapy: can treatment response determine the extent of neck dissection?

Abstract

The purpose was to determine if postradiotherapy (RT) neck dissection can be limited to the neck levels of residual adenopathy on post-RT computed tomography (CT). In all, 274 patients with lymph node-positive head and neck squamous cell carcinoma were treated with definitive RT. All patients had a contrast-enhanced CT performed 4 weeks after completing RT to evaluate tumor response. Two hundred eleven heminecks were dissected, either planned pre-RT or because of residual adenopathy on post-RT CT. CT images were reviewed to determine the presence and location of residual adenopathy. Radiographic complete response (rCR) was defined as lymph node size < or =1.5 cm and normal radiographic morphology (no filling defects or calcifications). For each neck level the CT findings were correlated with neck dissection pathology. Correlation of CT nodal response with neck dissection pathology revealed the following negative predictive values of rCR: level I, 100%; level II, 95%; level III, 98%; level IV, 96%; and level V, 96%. A subset analysis was performed on 61 neck levels with initially positive lymph nodes that completely responded to RT that were in a hemineck with residual lymphadenopathy elsewhere in the neck. Correlation of nodal response on CT to pathology indicated a negative predictive value of an rCR of 95% for this high-risk scenario. In 71 heminecks that underwent a selective neck dissection (defined as dissection of less than levels I-V) the 5-year neck control rate was 100%. rCR on post-RT CT has a negative predictive value of > or =95% for each neck level. This suggests that limiting neck dissection based on post-RT CT is safe.