Table 5. HPV association. IL: ipsilateral. BL: bilateral. PE:
panendoscopy. Ix: Investigation. Ex: examination. BOT: base of tongue,
PT: palatine tonsillectomy, TBM: tongue base mucosectomy
Diagnostic Procedures for the Tongue Base
Table 6 shows the eight studies which specifically look at the approach
to the tongue base29-36. Typically these patients have
already undergone a negative tonsillectomy or have palatine
tonsillectomy and tongue base sampling performed at the same time.
A variety of surgical techniques have been used in these studies,
including frozen sections, used as a decision node for simultaneous
palatine tonsil and tongue base procedures under one anaesthetic.
Overall, there is a lack of high quality evidence. The studies are
mainly retrospective and heterogenous in terms of workup. However, the
majority have had PETCT, EUA and biopsies, and often, where appropriate,
negative tonsillectomy prior to tongue base mucosectomy (TBM).
The detection rate for tongue base mucosectomy ranged from
1329-90%36. This is higher than the
pickup rates for random biopsies of
011-18%5 (table 1.1), suggesting
TBM is more effective than deep tissue biopsies.
There is variable practice with regard to approach to the contralateral
tongue base (table 5) but contralateral and/or synchronous rates is
reported in several studies. The rate of contralateral tongue base SCC
primaries ranged from 029,32-12%33(table 6). Durmus et al37 had an overall bilateral rate of 17.6% with
palatine tonsil rate of 66% and lingual tonsil rate of
33%4037 using TORS (table 7).
Across the studies included in this systemic review TBM haemorrhage
rates ranged between 032-8.5%38(table 6 and 7) most of which were managed conservatively. These include
alternative techniques.
HPV/P16 positivity rate was reported in many of these studies (table 6
and 7). There was a high rate of HPV positive cancers in those patients
with positive TBM. Several studies reported rates of up to HPV 100%
positivity for those with a tongue base
primary32,34,35 As with tonsillar primaries, HPV
positivity should prompt meticulous investigation of the oropharynx.