Impact of ¹⁸F-FDG PET/CT on the management of adrenocortical carcinoma: analysis of 106 patients.

PURPOSE: Adrenocortical carcinoma (ACC) is a rare and aggressive malignancy. Limited data are available about on value of (18)F-FDG PET/CT in ACC. We evaluated the impact of PET/CT on the management of ACC.

METHODS: We performed a retrospective review in patients with ACC who had undergone PET/CT. The impact of PET/CT on the management plan was evaluated by comparing the findings on PET/CT to the findings on contrast-enhanced CT. The sensitivity, specificity, and accuracy of each form of imaging were calculated. The correlations between PET/CT parameters, including maximum standardized uptake value (SUVmax), total lesion glycolysis, and decline in SUVmax after chemotherapy, and clinical outcome were evaluated.

RESULTS: Included in the analysis were 106 patients with 180 PET/CT scans. Of the 106 patients, 7 underwent PET/CT only for initial staging, 84 underwent PET/CT only for restaging, and 15 underwent PET/CT for both initial staging and restaging. PET/CT changed the management plan in 1 of 22 patients (5%) at initial staging and 9 of 99 patients (9%) at restaging. In 5 of the patients in whom PET/CT changed the management plan, PET/CT showed response to chemotherapy but contrast-enhanced CT showed stable disease. Sensitivity, specificity, and accuracy were 100%, 100%, and 100% for PET/CT at initial staging; 92.6%, 100%, and 96.4% for CT at initial staging; 98.4%, 100%, and 99.5% for PET/CT at restaging; and 96.8%, 98.6%, and 98.0% for CT at restaging, respectively. No PET/CT parameters were associated with survival at either initial diagnosis or recurrence.

CONCLUSION: PET/CT findings could substantially change the management plan in a small proportion of patients with ACC. Although lesion detection was similar between PET/CT and CT, PET/CT may be preferred for chemotherapeutic response assessment because it may predict response before anatomic changes are detected on CT.