Intratumoral Metabolic Heterogeneity of Cervical Cancer

Purpose: Previous research has shown that the intertumoral maximum standardized uptake value (SUV Max ) of F-18 fluorodeoxyglucose (FDG)–positron emission tomography (PET) for cervical cancer predicts disease outcome. The purpose of this study was to evaluate the pretreatment intratumoral metabolic heterogeneity of FDG. Experimental Design: This is a prospective cohort study of 72 patients with International Federation of Gynecology and Obstetrics stages Ib1 to IVa cervical cancer treated with chemoradiation. Three-dimensional FDG-PET threshold tumor volumes were calculated using image segmentation and an adaptive thresholding method for the primary cervix tumor from the pretreatment FDG-PET/computerized tomography. Intratumor heterogeneity was obtained for each patient's cervical tumor by taking the derivative (d V /d T ) of the volume-threshold function from 40% to 80%. The association between intratumoral heterogeneity and tumor-specific factors and patient outcomes were determined. Results: The mean cervix tumor SUV Max was 12.4 (range, 3.0-38.4). The mean differential tumor heterogeneity was −1.074 (range, −0.107 to −5.623). There was no association between d V /d T and SUV Max ( R 2 = 0.069), but there was a relationship with d V /d T and tumor volume ( R 2 = 0.881). There was no correlation of d V /d T with tumor histology ( P = 0.4905). Heterogeneity was significantly associated with the risk of lymph node metastasis at diagnosis ( P = 0.0009), tumor response to radiation as evaluated by FDG-PET obtained 3 months after completing treatment ( P = 0.0207), risk of pelvic recurrence ( P = 0.0017), and progression-free survival ( P = 0.03). Conclusions: Cervical intratumoral FDG metabolic heterogeneity on the pretreatment FDG-PET predicts risk of lymph node involvement at diagnosis, response to therapy, and risk of pelvic recurrence.