Impact of Radiation on Lymph Node Counts and Incidence of Extracapsular‐Spread in Neck Dissection Specimens

Abstract

Objectives: 1) Analyze the impact of preoperative radiotherapy on total lymph node yield in neck dissection specimens. 2) Analyze the impact of preoperative radiotherapy on the presence of extracapsular-spread in neck dissection specimens. Methods: Historical cohort study. Setting: Academic medical center. Patients: 525 subjects who underwent neck dissection for a diagnosis of squamous cell carcinoma from 1990 to 2010 were analyzed. Subjects were divided into 2 groups; those who underwent neck dissection alone or had neck dissection before radiation (surgery first group), versus subjects who received radiation therapy before neck dissection (radiation first group). Outcome Measures: The total number of lymph nodes harvested as well as the incidence of extracapsular-spread was examined between these two groups. Results: A total of 366 patients in the surgery first group and 159 in the radiation first group were analyzed. The mean number of lymph nodes harvested in the surgery first group was 29.4, compared to 20.9 lymph nodes in the radiation first group ( P < 0.001). Of 461 patients with available extracapsular-spread data, 106 (23.0%) had extracapsular-spread identified in their pathology report. Preoperative radiation significantly decreased the incidence of extracapsular-spread (OR=0.296, P < 0.001). The incidence of extracapsular-spread was 26.9% (84/312) in the surgery first group, and 14.8% (22/149) in the radiation first group. Conclusions: We identified a significantly decreased number of lymph nodes harvested and a decreased frequency of extracapsular-spread in the neck dissection specimens from patients who had undergone prior neck irradiation as compared to those without prior neck irradiation.