Evaluation of treatment efficacy according to RECIP 1.0 criteria in castration-sensitive prostate cancer.

[OBJECTIVE] To evaluate the relationship between treatment response and radiological progression-free survival (rPFS) in patients with metastatic castration-sensitive prostate cancer (mCSPC) assessed by PSMA-PET/CT using Response Evaluation Criteria on PSMA (RECIP 1.0) criteria.

[METHODS] In this study, 116 patients were analyzed retrospectively. At the beginning of the treatment and week 12 were PSMA PET/CT images evaluated for changes in total tumor volüme and new lesions. Patients were divided into four groups according to RECIP criteria; complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD). The primary outcome was the correlation of RECIP criteria with rPFS.

[RESULTS] Mean age of the patients was 67 years [IQR: 62-72]. Total of 116 patients; 65 (56%) hadPR, 17 (14,6%) SD, 19 (16,3%) PD, and 15 (12%) CR. rPFS was found to be statistically significantly different among these four groups (p < 0.001). RECIP PD was found to be significantly shorter rPFS compared with non-PD (p < 0.001), with an rPFS of 7 months (95% CI: 3.45-10.56). PSA values were measured at nadir in 40 patients and no patient in this group was evaluated as having PD.

[CONCLUSION] RECIP criteria have been shown to have prognostic significance in terms of evaluating treatment response and rPFS in mCSPC patients.