Prediction of hormonal resistance in metastatic prostate cancer with FDG PET/CT

Objectives To assess the association of FDG PET/CT with time to hormonal treatment failure (THTF) in men with metastatic castrate-sensitive prostate cancer.

Methods 76 patients with metastatic castrate-sensitive prostate cancer (mCSPC) underwent FDG PET/CT and were followed prospectively for THTF defined operationally as change to chemotherapy or death. Patients who were alive and who had not switched to chemotherapy were censored at the last follow-up date (up to 108 mo). Cox regression analyses were used to examine the association between PET/CT measurements (sum of SUVmax, maximum of SUVmax, and average of SUVmax of up to 10 most active lesions - range 0-10, median 2) and THTF. Survival probabilities were based on the Kaplan-Meier method.

Results 43 patients had THTF and 8 died without a documented hormonal treatment failure. Median time to THTF was 26.5 mo (95% CI: 15.5-46.6 mo). The THTF-free probability at 5 years was 35%+/-6%. In univariate analysis, all PET parameters including number of lesions were statistically significant for THTF. In a reduced multivariate model that accounted for inter-relationship among PET parameters, only sum of SUVmax (HR 1.01, 95%CI: 1.002-1.03, p=0.024) and number of lesions (HR 1.18, 95%CI: 1.08-1.29, p<0.001) were independently associated with THTF.

Conclusions FDG PET/CT provides independent prognostic information on THTF in men with mCSPC.

Research Support NIH-NCI grants R01-CA111613 (PI: H. Jadvar) and P30-CA014089.