Introduction:
The classification of oropharyngeal carcinomas (OPSCC) has been fundamentally changed
in the 8th edition of the TNM classification (TNM 2017) compared to the 7th edition
(TMN 2010). The aim of this study was to compare the prognostic accuracy of TNM 2010
and TNM 2017 for OPSCC in our own patient cohort.
Methods:
Retrospective analysis of overall (OS) and tumor specific survival (TSS) as well as
prognostic accuracy of TNM 2010 and 2017 in a predominantly surgically treated cohort
of 415 patients with OPSCC stage III-IVB (according to TNM 2010).
Results:
According to TNM 2010, 58 patients (14%) were in stage III, 308 (74.2%) in IVA, and
49 (11.8%) in IVB; according to TNM 2017, 30 patients (7.2%) were in stage I, 26 (6.3%)
in II, 74 (17.8%) in III, 162 (39.0%) in IVA and 123 (29.6%) in IVB. According to
Kaplan-Meier estimates, TNM 2010 accurately discriminates stage III, IVA and IVB (75%
TSS 48.6, 28.2 and 10.6 months, p = 0.0002; median OS 70.7, 68.4 and 21.2 months,
p = 0.00002). TNM 2017 fails to significantly discriminate III, IVA and IVB in the
analyzed cohort (75% TSS 28.2, 17.3 and 29.0 months, median OS 68.3, 53.9 and 41.9
months), but shows a significantly better prognosis for stage I and stage II. The
poor discrimination of OS and TSS in TNM 2017 is caused by a redistribution of 28
p16+ T4 OPSCC in stage III and 84 patients with extracapsular extension (ECE) of neck
nodes (now pN3b) in IVB.
Conclusion:
In p16+ patients, TNM 2017 predicts improved survival in stage I and II but is suboptimal
for survival estimation in T4 OPSCC. The redistribution of patients with ECE to stage
IVB does not accurately reflect their survival in the analyzed patient cohort.
