The value of 18F-FDG PET/CT in recurrent gynecologic malignancies prior to pelvic exenteration.

OBJECTIVE: In patients undergoing pelvic exenteration for recurrent gynecological malignancies, we assessed the performance of [(18)F]-FDG PET/CT for delineating disease extent and evaluated the association between quantitative FDG uptake metrics (SUVmax, total lesion glycolysis [TLG] and metabolic tumor volume [MTV]) and progression-free survival (PFS) and overall survival (OS).

METHODS: Retrospective study of patients undergoing pelvic exenteration for gynecologic malignancies between January 2002 and November 2011 who had FDG PET/CT within 90days before surgery. Two readers (R1, R2) independently determined the presence of bladder, rectum, vagina, cervix and pelvic side wall invasion and measured SUVmax, TLG and MTV in each patient. Areas under the curve (AUCs), for detecting organ invasion were calculated. Kaplan-Meier graphs were used to determine associations between FDG uptake and PFS/OS. Inter-reader agreement was assessed.

RESULTS: 33 patients (mean age 56years, range: 28-81) were included; primary sites of disease were the cervix (n=18), uterus (n=8) and vagina/vulva (n=7). AUCs for organ invasion ranged from 0.74 to 0.96. There was a significant association between FDG uptake metrics incorporating tumor volume (TLG and MTV) and OS (p≤0.001) as well as between MTV and PFS (p=0.001). No significant association was identified between SUVmax and OS/PFS (p=0.604/0.652). Inter-reader agreement for organ invasion was fair to substantial (k=0.36-0.74) and almost perfect for FDG quantification (ICC=0.97-0.99).

CONCLUSION: In patients undergoing pelvic exenteration for recurrent gynecological malignancies, (18)F-FDG PET/CT is useful for preoperative assessment of disease extent. Furthermore, quantitative metrics of FDG uptake incorporating MTV serve as predictive biomarkers of progression-free and overall survival in this population.