PET response criteria in solid tumors predicts progression-free survival and time to local or distant progression after chemotherapy with regional hyperthermia for soft-tissue sarcoma.

UNLABELLED: We evaluated the prognostic accuracy of established PET and CT response criteria in patients with soft-tissue sarcoma (STS) after combined chemotherapy plus regional hyperthermia (RHT).

METHODS: Seventy-three patients underwent (18)F-FDG PET/CT before and after 2-4 cycles of neoadjuvant chemotherapy with RHT for STS. Progression-free survival (PFS) and time to local and distant progression were among other factors correlated with response according to PET Response Criteria in Solid Tumors (PERCIST 1.0) and Response Evaluation Criteria in Solid Tumors (RECIST 1.1).

RESULTS: Metabolic response by PERCIST (n = 44/73) was an independent predictor for PFS (P = 0.002; hazard ratio [HR], 0.35; 95% confidence interval [CI], 0.18-0.68) and time to local or distant progression. Other independent predictors for PFS by multivariate analysis were adjuvant radiotherapy (P = 0.010; HR, 0.39; 95% CI, 0.20-0.80) and a baseline tumor size less than 5.7 cm (P = 0.012; HR, 0.43; 95% CI, 0.22-0.83). Response by RECIST 1.1 was seen in a small group of patients (n = 22/73) and allowed prediction of PFS for patients with sarcoma outside the abdomen (P = 0.048; HR, 0.13; 95% CI, 0.02-0.98).

CONCLUSION: Metabolic response by (18)F-FDG PET predicts PFS and time to local and distant progression after 2-4 cycles of neoadjuvant chemotherapy plus RHT for STS.