pRECIST: Guidelines for Response Criteria for Use in Trials Testing Therapeutics in Pancreatic Cancer

IMPORTANCE: Pancreatic tumor response to treatment remains challenging and varies greatly. In order to establish a standardized approach to measuring and evaluating pancreatic tumor metabolic activity (MA), a consensus guideline called Pancreatic RECIST (pRECIST) was developed. This guideline is based on modified Response Evaluation Criteria in Solid Tumors (RECIST version 1.1), incorporating concurrent CT/PET scan quantitative assessments. OBJECTIVE: The aims were to ensure consistent design, data collection, and validation of the guideline. DESIGN: Prospective consensus guideline structure with prospective patient data evaluation and validation. MAIN OUTCOME MEASURES: pRECIST provides definitions for objective changes in tumor size and metabolic activity, specifically for trials that utilize all available therapies. Moreover, it outlines the minimum data requirements for future and ongoing trials to facilitate the creation of a comprehensive data warehouse for later validation of pRECIST. RESULTS: Two readers independently reviewed imaging data of all patients. In case of disagreement, a third reader adjudicated the reads. Readers assessed lesions based on RECIST 1.1 criteria and measured SUV values on PET images. All patients were reviewed successfully based on the pRECIST guideline. The most common response at 3 months was unconfirmed stable disease and/or progressive disease based on the primary target lesion size change and characteristics that were not adjudicated on just PET imaging. CONCLUSION: pRECIST is a novel and valuable response criterion for local pancreatic tumor response. Given the multitude of clinical trials being conducted or planned for pancreatic cancer, particularly in the neoadjuvant stage, this guideline will enable consistent conduct, interpretation, and analysis of these trials.