Survival effect of postoperative radiotherapy combined with lymph nodes examined on cavity squamous cell carcinoma patients with stage T1-2N1M0: a propensity‑adjusted SEER database analysis

Abstract

Background To explore the association between postoperative radiotherapy (PORT) combined with lymph nodes examined (LNE) and the survival outcome for pT1-2N1M0 oral cavity squamous cell carcinoma (OCSCC) patients. Methods This study retrieved patients who underwent dissection of primary site and neck lymph nodes for pT1-2N1 OCSCC without adverse nodal features from the Surveillance, Epidemiology, and End Results database from 2004 to 2015. Patients were divided into groups according if PORT was conducted. Propensity score matching (PSM) analysis was conducted and the best cut-off value of the LNE was determined by X-tile. Cancer-specific survival (CSS) was the primary outcome. Univariable and multivariable analyses were performed to assess the relation between PORT and CSS, adjusting for other prognostic factors. Results A total of 469 patients were finally enrolled according to our exclusion criteria and then 170 pairs of patients were matched by PSM. The best cut-off value of the LNE was determined by X-tile, stratifying patients into LNE ≤ 16 group and LNE > 16 group. For the whole matched cohort, whether patients chose PORT had no correlation with other factors (all p > 0.05), and it revealed that PORT made no contribution to a better survival outcome for patients (p = 0.253). While stratified by the LNE, among the LNE ≤ 16 group, a statistically significant improved CSS was found for those who undertook PORT (hazard ratio, 0.521; 95% confidence interval, 0.294–0.925; p = 0.022). Conclusions The PORT made no contribution on CSS of OCSCC patients with pT1-2N1M0 stage on the whole cohort. While among the LNE ≤ 16 group, PORT conferred a superior CSS compared with surgery only, indicating the necessity for surgeons to conduct a thorough neck dissection.

The Benefit of Postoperative Radiotherapy and Extending Neck Dissection in pT1-2 Oral Squamous Cell Carcinoma With a Single Ipsilateral Cervical Lymph Node Metastasis (pN1)

“…In an effort to provide a sufficient answer and an evidencebased recommendation for the relatively rare case of pT1-2 pN1 situation, several retrospective studies have been carried out (8)(9)(10)(11)(12)(13)(14). Among the relatively inhomogeneous studies, including different adverse pathological features, competing risk factors and patients' characteristics, publications analyzing the US National Cancer Database have drawn attention, mainly because of the large number of patients included in the analyses (15)(16)(17).…”