The 14 eligible studies included a total of 1780 patients, of which 294
underwent ND as their single primary treatment for HNSCCUP. There were
on average 17.5 (5-63) (median(range)) cases per study. Although all
studies met the initial eligibility criteria and presented outcome data
relevant to the primary and / or secondary aims, there was significant
heterogeneity in reporting parameters, precluding any meta-analysis.
There was a male preponderance, ranging from 76-88% across the studies,
with an average age of 55-65 years. Four (28.6%) of the studies
reported on p16 status, with one (7.1%) also reporting on high-risk HPV
status by in situ hybridisation. In these studies, data were incomplete,
with anywhere between 19.1% and 86.7% of included patients having
status recorded.
The studies were evaluated for quality of diagnostic investigations
compared to perceived ‘gold standards’ (FDG PET-CT, MRI, panendoscopy,
tonsillectomy, tongue base mucosectomy). No single study included all
investigations prior to treatment. PET-CT was performed on all patients
in two studies (53,58) and on a proportion (20.0-58.6%) of patients in
a further eight studies (50,54,56,57,59–62). Three studies (51,55,63)
made no mention of cross-sectional imaging being performed, with the
remainder confirming all patients underwent either CT or MRI scan prior
to treatment. One study (51) didn’t state if panendoscopy was performed
and in two further studies only a proportion (45.1-64.0%) underwent
panendoscopy (56,63). Tonsillectomy was undertaken for all patients in
nine of the studies; a proportion of patients (5.8-41.7%) in three of
the studies (50,56,63), and was not stated in two studies (51,55). Only
one study reported on tongue base mucosectomy, stating that all patients
had this procedure (52).
All the studies reported data on the nodal status (AJCC/UICC TNM7) of
patients treated; however only half provided discernible data on nodal
status for patients undergoing ND alone, totalling 132 of the 294
patients (44.9%). Of these, the breakdown of nodal status was: N1 (n=
35,26.5%), N2a (n= 28, 21.2%), N2b (n =58, 43.9%), N2c (n=4, 3.0%),
and N3 (n=7, 5.3%).
Follow up duration was reported in 10 studies (n=800), but none
specified follow up timeframes for ND only patients, median follow up
duration ranged from 31.1 to 83.5 months, 6 studies reported a lower end
range of follow up <12 months post treatment, which may impact
interpretation of this data. Data for survival, primary emergence,
recurrence, or metastasis was not stratified by p16 status in any of the
studies.