Purpose: the aim of this retrospective study was to evaluate the frequency of distant metastases (DM) and to define factors that influence DM free survival (DMFS) in patients with head and neck squamous cell carcinoma (HNSCC).
Methods: the charts of 201 patients with oral cavity, pharyngeal, or laryngeal carcinoma, treated with postoperative radiotherapy (RT) or definitive RT between 1999 and 2004 and achieved locoregional control were analyzed.
Results: DM occurred in 26 of 201 (12.9%) patients. The mean time of DM diagnosis was 16.5 months (range 5-35). The median time to death after diagnosis of DM was 5 months (range 1-13). The DMFS rate at 5 years was 84.8%. Univariate analysis demonstrated that the risk of DM was significantly influenced by age (p=0.047), cigarette smoking (p=0.024), ECOG performance status (PS) (p=0.008), location of the primary site (p=0.003), N stage (p<0.0001), overall stage (p<0.0001), histological differentiation (p<0.0001), levels of nodal involvement (p<0.0001), treatment modality (p<0.0002), presence of locoregional recurrence (LRR) (p<0.0001), and time to LRR (p<0.0001). In multivariate analysis nodal involvement (N1: p=0.007; N2: p=0.036; N3: p=0.043), and the time to LRR ≤ 6 months (p=0.037) were proven as independent factors that significantly influenced DMFS.
Conclusion: development of DM in patients with HNSCC was significantly influenced by the presence of positive nodal status and the presence of LRR whose appearance was within 6 months of RT.