For patients with metastatic castration-resistant prostate cancer (mCRPC), Response Evaluation Criteria In prostate-specific membrane antigen (PSMA)-positron emission tomography/computed tomography (PET/CT; RECIP) 1.0 is prognostic for overall survival, according to a study published in the April issue of the Journal of Nuclear Medicine.
Andrei Gafita, M.D., from the University of California in Los Angeles, and colleagues conducted an international, multicenter, retrospective study involving 124 men with mCRPC who underwent 177Lu-PSMA therapy and received PSMA-PET/CT at baseline and interim at 12 weeks (bPET and iPET, respectively). Three blinded readers examined pairs of bPET and iPET for appearance of new lesions. After segmentation of tumor lesions, the total PSMA-positive tumor volume (PSMA-VOL) was calculated. The appearance of new lesions and changes in PSMA-VOL were combined to develop RECIP 1.0, which was defined as complete response, partial response (RECIP-PR), progressive disease (RECIP-PD), and stable disease (RECIP-SD). In addition, changes in prostate-specific antigen (PSA) levels at 12 weeks were recorded.
The researchers found that compared with patients with RECIP-SD and RECIP-PR, those with RECIP-PD had shorter overall survival (8.3 months versus 13.1 and 21.7 months, respectively). Compared with PSA only, PSA+RECIP had superior C-indices for identifying responders and progressors (0.65 versus 0.62 and 0.66 versus 0.63, respectively).
“RECIP 1.0 was developed as an evidence-based novel framework to assess tumor response early in the course of the treatment in mCRPC using PSMA-PET/CT,” the authors write. “PSMA-PET/CT can be used as a response biomarker to monitor early efficacy of 177Lu-PSMA and potentially to other mCRPC treatments.”
Several authors disclosed financial ties to the biopharmaceutical industry.
Source: HealthDay News