Prognostic value of 18 F-FDG PET/CT in postoperative recurrence of retroperitoneal liposarcoma: a single-center retrospective study.

OBJECTIVE

Recurrence is the leading cause of tumor-related death in retroperitoneal liposarcoma (RPLPS). Variant subtypes of RPLPS determine different recurrence 18 F]-fluoro-2-deoxy-D-glucose ( 18 F-FDG) PET/computed tomography (PET/CT). This study analyzed the characteristics of different histologic subtypes of 18 F-FDG PET/CT and their associations with recurrence and prognosis.

METHODS

Clinical-pathological information, 18 F-FDG PET/CT data, recurrence, and progression-free survivals (PFS) of 83 patients with RPLPS were collected. Maximum and peak standardized uptake values (SUV max and SUV peak , respectively) and mean CT value (CT mean ) of tumors were measured and correlated with histologic subtype. Receiver operating characteristics (ROC) curves were used to analyze the predictability for subtype and recurrence. Kaplan-Meier analysis examined SUV max and SUV peak as recurrence risk factors.

RESULTS

Studied patients with different types of liposarcomas. Dedifferentiated liposarcomas (DDLPS) had higher SUV max and SUV peak than well-differentiated (WDLPS) and myxoid/round cell (MLPS) types. WDLPS had lower CT mean values compared to MLPS and DDLPS. Using ROC curves, determined cut-off values for SUV max (5.1) to differentiate DDLPS, SUV peak (3.0) for WDLPS, and CT mean (12.3 Hu) for WDLPS. These cut-offs were found to be best for predicting recurrence. Kaplan-Meier analysis showed that histologic subtype, SUV max , and SUV peak were all linked to recurrence-free survival.

CONCLUSIONS

The use of SUV and CT features on 18 F-FDG PET/CT imaging may increase confidence in subtype diagnosis. Patients with SUV max  > 5.1 or SUV peak  > 3.0 suggest a poor prognosis.