Lymph node ratio relationship to regional failure and distant metastases in oral cavity cancer.

Background We aimed to investigate the impact of lymph node ratio (LNR, number of positive nodes/total number of excised nodes) on regional-only-failure, distant-only-failure and overall survival (OS) in oral squamous cell carcinoma (OSCC). Methods Retrospective review of pN0-2 OSCC-patients (1994–2012) treated with curative-surgery with neck dissection ± postoperative radiotherapy (PORT) ± concurrent chemotherapy. LNR was subjected to multivariable analysis (MVA) of regional-only-failure, distant-only-failure and OS. Results Overall 914 patients were identified; median follow-up: 51 months (1–189); pN0: 482 (52.7%), pN1: 128 (14%), pN2a: 6 (0.7%); pN2b: 225 (24.6%); pN2c: 73 (8%); median number of dissected nodes: 36 (6–125); median number of pN+: 2 (1–49); median LNR for pN+ patients: 6%; extranodal extension: 187 (20.5%). Bilateral neck dissection: 368 (40.3%); PORT: 452 (49.5%); and concurrent chemotherapy: 80 (8.8%). High grade, lymphovascular invasion perineural invasion and pT3–4 were associated with high LNR. On MVA, LNR was associated with regional-only-failure (HR = 1.06; 95%CI: 1.04–1.08; p < 0.001), distant-only-failure (HR = 1.03; 95%CI: 1.02–1.05; p = 0.004) and lower OS (HR = 1.03; 95%CI: 1.02–1.05; p < 0.001). Similarly, in pN2-subgroup: LNR was associated with regional-only-failure (HR = 1.04; 95%CI: 1.02–1.06; p < 0.001), distant-only-failure (HR = 1.03; 95%CI: 1.01–1.06; p = 0.045) and lower OS (HR = 1.03; 95%CI: 1.02–1.04; p < 0.001). Conclusion High LNR is associated with higher regional-only-failure/distant-only-failure and lower OS. LNR should be assessed in future prospective trials for selection of adjuvant therapy. [ABSTRACT FROM AUTHOR]