Survival
In general, studies with a greater proportion of early N-stage patients treated with ND only tended to have improved survival. In Milleret al. (53) 88.9% of ND only patients had N1 or N2a disease, with a 3-yr DFS and OS of 66.7% and 100%, respectively. Furthermore, they report that in the 7 patients that were treated for N1 disease without evidence of extracapsular spread (ECS) progression-free survival (PFS) was 100%. In Mizuta et al . (58) 55.5% of ND only patients had N1 or N2a disease with 3-year disease specific survival (DSS) of 81.8% and 3-yr distant metastasis free survival (DMFS) of 88.6%. Whilst Iganej et al. (55) and Patel et al . (54) do not provide as detailed data the authors summarised that there was a ‘5-yr tumour control rate of 81% for N1 and N2a disease without ECS’ and a ‘100% ipsilateral regional control for pN1’ respectively. In contrast to this, Dou et al . (61) and Wongsritrang et al . (63) report only 10.4% and 17.3% of their whole cohort had N1 disease respectively, whilst the authors do not report on the N-stage for surgery only, we surmise that the lower 3-yr DFS & OS observed for ND only is reflective of this (42.8%, 87.5% and 54.5%, 43.9% respectively). Furthermore, these studies were conducted in China and Thailand, respectively, where a putative primary site is more likely to be nasopharyngeal (65), further limiting the interpretation of these findings in Western practice.
None of the studies included in this review could identify a survival benefit for primary radiotherapy over primary surgery, and some could not find a survival benefit for any particular combination of treatment modalities (51,58). However, four of the studies demonstrated improved survival when ND formed part of initial multi-modality treatment (50,59,60,62).