Pretreatment primary tumor SUVmax measured by FDG-PET and pathologic tumor depth predict for poor outcomes in patients with oral cavity squamous cell carcinoma and pathologically positive lymph nodes.

Abstract

The pathologic tumor depth is an independent prognosticator for local control (LC) and survival in patients with oral cavity squamous cell carcinoma (OSCC). We sought to investigate the prognostic value of the preoperative maximal standardized uptake value (SUVmax) at the primary tumor in OSCC patients with pathologically positive lymph nodes. A total of 109 OSCC patients with pathologically positive lymph nodes were investigated. All patients underwent 2-deoxy-2[(18)F]fluoro-d-glucose-positron emission tomography within 2 weeks before surgery and neck dissection. All patients were followed for >or=24 months after surgery or until death. The optimal cutoff value for the primary tumor SUVmax was selected according to the 5-year LC rate. Independent prognosticators were identified by Cox regression analysis. The median follow-up for all patients was 26 months (39 months for surviving patients). A cutoff SUVmax of 19.3 provided the greatest prognostic information for the 5-year LC rate (55% vs. 88%, p = 0.0135). A tumor depth >or=12 mm appeared to be the most appropriate cutoff for predicting the 5-year LC rate (76% vs. 95%, p = 0.0075). A scoring system using the primary tumor SUVmax and tumor depth was formulated to define distinct prognostic groups. Patients with both a SUVmax of >or=19.3 and tumor depth of >or=12 mm (n = 8) had significantly poorer 5-year LC, 5-year disease-free, 5-year disease-specific, and 5-year overall survival rates compared with the other patient groups. The combination of the primary tumor SUVmax (>or=19.3) and pathologic tumor depth (>or=12 mm) identified a subgroup of OSCC patients at greatest risk of poor LC and death.