Purpose To investigate the prognostic
significance of standardized uptake value (SUV)
of metastatic neck lymph nodes measured on
FDG PET/CT in patients with stage IV
oro/hypopharyngeal cancers treated by definitive
chemoradiotherapy (CCRT).
Methods Retrospective analysis of 65 patients
with clinically N+ stage IV SCC of the
oro/hypopharyngeal squamous cell carcinoma
(SCC) who underwent FDG PET/CT scans for
primary staging. Follow-up continued till death
or at least 24 months from the start of treatment.
The primary study endpoint was neck control
(NC). The log-rank test and Cox proportional
hazard analysis were used to identify significant
prognostic factors.
Results The 3-year NC rate was 53%. In
univariate analysis, N3 status and nodal SUV ≥
9.8 were significantly associated with reduced
NC. In multivariable analyses, nodal SUV
retained its independent prognostic significance
as a predictor of NC. Lymph node stage was an
independent predictor of disease specific survival
(DSS). A prognostic scoring system was
constructed as follows: score 0 = N0-N2 and
nodal SUV < 9.8; score 1 = N3 or nodal SUV ≥
9.8; and score 2 = N3 and nodal SUV ≥ 9.8.
Patients with a score of 2 showed the worst NC
(hazard ratio [HR], 95% confidence interval [CI]= 10.5, 3.3-33.1; P < 0.001) and the lowest DSS
(HR, 95% CI = 6.4, 2.2-18.7; P = 0.001).
Conclusion The combination of high nodal SUV
and N3 neck disease identifies a subgroup of
high-risk stage IV oro/hypopharyngeal SCC
patients. Further prospective studies are
warranted to validate this finding.