Prediction for distant failure in patients with stage M0 nasopharyngeal carcinoma: the role of standardized uptake value.

Distant failure is an important cause of death in stage M0 primary nasopharyngeal carcinoma (NPC). However, a reliable prognosticator for occurrence of distant failure was lacking. Thus, we conducted this study to investigate prospectively the role of standardized uptake value on 18F-FDG for predicting distant failure in stage M0 NPC. Patients with stage M0 primary NPC diagnosed by both conventional work-up (CWU) and 18F-FDG PET were enrolled. Survival was estimated by the Kaplan-Meier method. Cox proportional hazards models were used to identify independent prognosticators. Between January 2002 and July 2003, 65 NPC patients were investigated. Up to the date of analysis, 12 patients died and 13 patients experienced recurrences, among whom 9 had distant failures. The 5-year overall survival (OS), relapse-free survival (RFS), and distant relapse-free survival (DRFS) were 81.2%, 79.2%, 84.4%, respectively. In multivariate analysis, the following risk factors for poor prognosis were identified: T3-4 (p=0.033) for RFS; and maximal standardized uptake value (SUVmax) of the primary tumor > 12.0 (p=0.012), stage IVa-b (p=0.037), and N2-3 disease (p=0.04) for DRFS. The 5-year DRFS in stage IVa-b patients with SUVmax > 12.0 was significantly lower than that in stage I-III patients with SUVmax < or = 12 (p=0.0001). None of the patients in the latter group developed distant failure. In conclusion, a SUVmax > 12.0 of the primary tumor represents a "metabolic phenotype" for occurrence of distant failure in stage M0 NPC patients. And the combined information of SUVmax and tumor staging can guide the use of neoadjuvant/adjuvant therapy and surveillance protocols to improve distant control.