Clinical implementation of RECIP 1.0

Abstract

Prostate cancer remains a major global health burden, and the integration of PSMA-targeted PET imaging and radioligand therapy has transformed diagnostic and therapeutic strategies for advanced disease. Traditional response assessment tools-such as PSA kinetics, CT, bone scans, and composite criteria like PCWG3 or RECIST-are limited by PSA flare phenomena, inability to evaluate bone-only disease, and lack of sensitivity for early metastatic changes. To address these limitations, the Response Evaluation Criteria in PSMA PET/CT (RECIP 1.0) was developed as the first evidence-based framework leveraging PSMA PET imaging for treatment response evaluation. RECIP 1.0 incorporates changes in PSMA-positive total tumour volume and the appearance of new lesions, enabling stratification into complete response, partial response, stable disease, or progressive disease. It has demonstrated strong prognostic value for overall and progression-free survival and supports standardized reporting essential for clinical trials. A visual RECIP method further enhances feasibility in routine practice, showing excellent concordance with quantitative software-based segmentation. Although challenges remain, particularly the labor-intensive nature of tumour segmentation and variability across imaging protocols emerging AI-based automated tools are poised to streamline RECIP implementation. As PSMA-based theranostics continue to expand, RECIP 1.0 offers a robust and clinically meaningful framework for response assessment.