Total lesion glycolysis: a possible new prognostic parameter in oral cavity squamous cell carcinoma.

OBJECTIVES: We sought to determine potential prognostic value of total lesion glycolysis (TLG) calculated from combined positron emission tomography/computed tomography (PET/CT) in patients with oral cavity squamous cell carcinoma (OSCC). MATERIALS AND METHODS: We prospectively studied 126 patients with OSCC who underwent PET/CT before definitive treatment by radical surgery. The metabolic tumor volume (MTV) was calculated for the primary tumor according to an absolute standardized uptake value (SUV) of 3. TLG was calculated as MTV × the average SUV. The nodal SUVmax was also recorded. The median value of SUVmax and TLG were used to divide the patients into two categories (high and low). Patients were followed up until death or for at least 24 months from their surgery. Disease-free (DFS) and disease-specific survivals (DSS) were the main outcome measures. RESULTS: The median TLG of the primary tumor ((T)TLG) was 71.4, and the median nodal SUVmax ((N)SUV) was 7.5. Patients with high (T)TLG (≥ median) had a 2-year DFS of 52% whereas the DFS was 74% for those with a low (T)TLG (P=0.007); the 2-year-DSS rates were 53% vs. 84%, respectively (P<0.001). Similarly, patients with high (N)SUVmax (≥ median) had a 2-year DFS of 42% vs. 70% for patients with a low (N)SUVmax (P=0.001); the 2-year-DSS rates were 39% vs. 78%, respectively (P<0.001). In multivariate analyses, (T)TLG, (N)SUVmax, and pathological nodal status were independent prognostic factors for the 2-year DSS. A 3-point prognostic scoring system was formulated based on the presence or absence of the independent factors. Patients with positive neck nodes, high (N)SUVmax, and high (T)TLG (score 3) had a 32-fold higher risk of cancer death compared with those lacking such risk factors (2-year-DSS=26% vs. 97%, P<0.001). CONCLUSION: Primary tumor TLG is an independent prognostic factor for cancer control and survival in patients with OSCC. A prognostic scoring system that includes primary tumor TLG, nodal SUVmax, and pathological neck status may be useful for risk stratification in this group of patients.

Comparison of PET/CT and MRI for the detection of bone marrow invasion in patients with squamous cell carcinoma of the oral cavity.

Our aim was to retrospectively assess the diagnostic performance from combined positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) for the detection of bone marrow invasion of the mandible or maxilla in patients with oral cavity squamous cell carcinoma (OCSCC). A total of 114 patients with OCSCC, arising from or abutting the upper or lower alveolar ridge, underwent staging PET/CT and MRI studies before surgery. The possibility of bone marrow invasion on PET/CT and MRI was graded retrospectively on a 5-point score. Histopathology was taken as the reference standard. Sensitivity, specificity, predictive values and likelihood ratios were calculated. Clinical factors affecting the performance, like tumor origin and dentate status were also explored. PET/CT was found to be more specific than MRI (83% vs. 61%, respectively, p=0.0015) but less sensitive (78% vs. 97%, respectively, p=0.0391). Dentate status and tumor origin affected the diagnostic performance of PET/CT. In patients with positive MRI, sensitivity and specificity of PET/CT were 78% and 100% in dentate patients with alveolar ridge tumors, 75% and 80% in dentate patient with buccal tumors, 90% and 33% in edentulous patients with alveolar ridge tumors and 0% and 63% for edentulous patients with buccal tumors, respectively. PET/CT is more specific than MRI and can be used to complement the role of MRI. A negative MRI result can confidently exclude the presence of bone marrow invasion, while in patients with positive MRI findings, a negative PET/CT may be useful to rule out bone marrow invasion in dentate patients.