Impact of Radiotherapy on Neck Dissection Nodal Count in Patients With Head and Neck Cancer

Objectives/Hypothesis Our study aimed to review the impact of preoperative radiotherapy (RT) and other factors on the lymph node count of neck dissection (ND) specimens from patients with head and neck cancer (HNC). A retrospective study was conducted on all patients with head and neck cancers who had undergone NDs in Singapore General Hospital between 1992 and 2013. Study Design Retrospective study. Methods Patients were categorized into two groups: patients treated with RT with or without chemotherapy before ND and patients who had undergone ND surgery without previous history of RT. The primary endpoint for this study would be the lymph node count from ND. Results The study cohort consists of 1,024 NDs on 829 patients. There were 597 (58.3%) radical/modified radical NDs involving levels I–V. Within this group, 75 (12.6%) NDs had preoperative RT. Preoperative RT and age were found to significantly reduce nodal yield in both univariate and multivariate analysis in the radical/modified radical ND subgroup. In our multivariate analysis, preoperative RT was shown to decrease the nodal yield by 7.464 (P = .0002, 95% confidence interval [CI]: −11.35 to −3.58). Advanced age independently decreases nodal yield, even after accounting for the effect of RT (P = .0002, 95% CI: −0.27 to −0.08). In addition, preoperative RT has a more pronounced effect in reducing lymph node count in the older age group. Conclusions Preoperative RT and advanced age are independent and synergistic factors that reduce nodal count from NDs in patients with head and neck cancers. Level of Evidence 4 Laryngoscope, 130: 1947–1953, 2020