ESTRO 2024 - Abstract Book

S2435

Clinical - Urology

ESTRO 2024

1. Deek, M. P. et al. Long-Term Outcomes and Genetic Predictors of Response to Metastasis-Directed Therapy Versus Observation in Oligometastatic Prostate Cancer: Analysis of STOMP and ORIOLE Trials. J Clin Oncol 40, 3377 – 3382 (2022).

1434

Digital Poster

Clinical utility and impact on the therapeutic management of PET 18F-PSMA DCFPyL in prostate cancer

Francesco Amorelli 1 , Pedro J Plaza 2 , Jose M Torices 3 , Augusto O Natali 4 , Alvaro Martinez 1 , Javier Sanz 1 , Ismael Membrive 1 , Manuel Algara 1 , Palmira Foro 1 1 Hospital del Mar, Radiation Oncology, Barcelona, Spain. 2 Hospital del Mar, Nuclear Medicine, Barcelona, Spain. 3 Hospital Quiron Salud, Radiation Oncology, Barcelona, Spain. 4 Hospital Josep Trueta, Laboratory Medicine, Girona, Spain

Purpose/Objective:

To analyze the clinical utility and disease detection rate of PET-PSMA compared to conventional diagnostic study in patients with biochemical relapse of prostate cancer after primary treatment with radical intent and low PSA values.

To analyze possible changes in therapeutic management based on positive PET-PSMA results.

Material/Methods:

We retrospectively selected 85 patients diagnosed with biochemical relapse of prostate cancer after primary treatment with radical intent (radiotherapy or surgery) and low PSA values (< 2 ng/ml). All selected patients had other negative imaging tests (ultrasound, CT-Scan, MRI, GGO and/or PET-Choline). All patients underwent a study with 300-350MBq PSMA-18F DCFPyL PET/CT. The assessment was performed by two expert nuclear physicians. The disease detection rate (DR) was evaluated in relation to clinical and biochemical variables, as well as the optimal cut-off points for PSA (ng/ml) and PSA dubbing time (DT-PSA) in months according to RoC curves. After a follow-up of no less than six months we assessed changes in the therapeutic management of patients directly related to positive PET-PSMA results. Clinical and therapeutic evaluation was performed by expert radiation oncologists. Descriptive statistical analysis was performed. RoC curves (sensitivity vs. 1-specificity) and the corresponding areas under the curve were calculated to assess the predictive power of the study. For descriptive statistics quantitative variables were described through mean and standard deviation. Qualitative variables were described through frequencies table (number and percentage). Between group comparisons were performed for negative vs positive results. Statistical tests used for these comparisons were Chi-square or Fisher exact, as appropriate, for categorical variables and Mann – Whitney U for continuous variables. Finally, multivariate logistic regression was performed to check factors associated with positive results. Variables in the multivariate analysis were introduced on the basis of clinical criteria taking into account those that were statistically significant or nearly significant (p 0.05-0.1) in the