Measurement of tumor volume by PET to evaluate prognosis in patients with head and neck cancer treated by chemo-radiation therapy

Abstract

Purpose. To evaluate the prognostic value of the metabolic tumor volume measured on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging and other clinical factors in patients treated for locally advanced head-and-neck cancer (HNC) at a single institution. Materials and methods. Between June 2005 and August 2008, 59 patients with HNC that underwent pretreatment FDG-PET studies received neoadjuvant chemotherapy and radiation therapy. Metabolically active tumor regions were delineated on the pretreatment PET scans by a fixed SUV of 2.5. We evaluated the relationship of the 18F-fluorodeoxyglucose-PET maximum standardized uptake value (SUV) and the metabolic tumor volume (MTV) with the progression-free survival (PFS) and overall survival (OS). Results. The MTV and lymph node metastasis were predictive of the PFS and OS. The lymph node status did not correlate with the MTV. A higher MTV of 9.3 cm³ was significantly associated with an increased risk of recurrence (2.19-fold, p = 0.006) and death (1.62-fold, p = 0.051). Separation of patients with tumor volumes ≤ 9.3 cm³ and no lymph node disease vs. any other combination was strongly predictive of the PFS and the OS. Conclusions. MTV and lymph node status were prognostic values associated with survival. Quantitative measurement of tumor volume separates patients with a good prognosis from those with a poorer prognosis. A subset of patients with relatively small tumors and no lymph node involvement did very well.