Background: The aim of this study was to analyze the prognostic importance of extracapsular nodal spread (ECS) in patients with locally advanced squamous cell carcinoma (SCC) of the oral cavity or oropharynx, and the impact of adjuvant low single dose cisplatin-based radiochemotherapy on distant metastases-free survival (DMFS).
Patients and methods: The study population was selected from 195 patients with high-risk oral cavity or oropharyngeal cancer, who had either adjuvant radiotherapy (RT) or radiochemotherapy (RCT) between January 1, 1997 and December 31, 2006, at the University Clinic of Radiation Oncology of the Martin-Luther-University Halle-Wittenberg. A total of 42 matched pairs of patients with UICC stage III-IVa,b disease were analyzed. The patients were matched (one to one) according to tumor site, sex, T stage, N stage, ECS, resection margin status, and Karnofsky performance status. To analyze the correlation between the treatment modality (RT vs. RCT) and the impact of ECS on DMFS, the Cox proportional hazard model was used. Survival rates were calculated using the Kaplan-Meier method.
Results: There was a strong correlation between the degree of nodal involvement and ECS (pN1: 33%; pN2b: 45%; pN2c: 71%). Moreover, the 5-year locoregional control rates (LC) in patients with ECS were 76% vs. 63% (n.s.) for RT and RCT, respectively. However, for patients without ECS, the LC was more favorable after RCT (RT vs. RCT: 62% vs. 88%, p < 0.05). DMFS again was better after RT, and this observation was independent of the presence or absence of ECS. Finally, in multivariate analyses, the presence of ECS significantly decreased the DMFS (p = 0.04, hazard ratio (HR) 2.64).
Conclusions: Patients with ECS have an increased risk of distant metastases. Adjuvant low single dose cisplatin-based concurrent chemotherapy seems to have no influence on occult microscopic systemic disease.