Abstract
1652
Objectives To evaluate whether the detection rate (DR) of 18F-Choline (18F-CH) PET/CT is negatively influenced by androgen deprivation therapy (ADT) in patients with prostate cancer (PC) already treated with radical intent, who present biochemical relapse.
Methods We have retrospectively evaluated data of 325 patients with PC (mean age: 69.7 years), who were referred to our centre to perform 18F-CH PET/CT for biochemical relapse (PSA range: 0.1-80ng/ml, mean: 5.5ng/ml). At the time of the scan, 139 patients (42.8%) were under ADT. The relationship between the DR of 18F-CH PET and possible clinical predictors (trigger PSA and ADT) was investigated using univariate and multivariate binary logistic regressions. The correlation between the DR of 18F-CH PET and trigger PSA was also investigated by dividing patients in 6 groups according to their PSA level. Possible influence of ADT on the DR of 18F-CH PET was evaluated by considering the DR in patients under ADT and in those not under ADT at the time of the examination.
Results The overall DR of 18F-CH PET was 58.2% (189/325 patients). In both univariate and multivariate logistic regression analysis, trigger PSA and ADT were significantly correlated to the DR of 18F-CH PET (p<0.05). The DR of 18F-CH PET progressively increased with the increasing of trigger PSA. Patients under ADT (mean PSA 7.8ng/ml) presented a higher DR of 18F-CH PET than those not under ADT (mean PSA 3.9ng/ml): 70.5% and 48.9% respectively; p<0.001.
Conclusions The overall DR of 18F-CH PET was 58% and was significantly correlated to trigger PSA and ADT. ADT at the time of the examination did not negatively influence the DR of 18F-CH PET, in patients with PSA elevation despite the ongoing ADT (hormone resistant patients), and should not be withdrawn before performing 18F-CH PET, on the contrary, it was associated to a higher DR of 18F-CH PET.