Standardizing radiologic reporting of response to improve the patient experience: Comparing response categories of RECIST 1.1 and a novel, real-world, standardized, oncologic response lexicon derived from clinical radiology reports.

e13810 Background: With the 21st Century Cures Act of 2016, rapid and complete access to medical records including radiology reports is mandated. Patients have expressed that an unmet need is improving clarity in radiology results with more structured information that avoids technical jargon. RECIST is routinely applied in clinical trials to assess treatment response but is challenging to apply in routine practice. A standardized Oncologic Response (OR) lexicon was developed to categorize response and progression directly from clinical reports, using an ordinal scale. This study aims to compare the rates of response from OR categories to RECIST categories in the setting of three phase 2 trials. Methods: Patients from three phase 2 trials were retrospectively reviewed for real world response using OR categories by a radiologist blinded to RECIST data. Clinical radiology reports generated during the trial period were reviewed and response was categorized from the report impression text according to OR categories (OR-0: no evidence of disease, OR-1: unequivocal decrease, OR-2: slight decrease, OR-3: unchanged, OR-4: slight increase, and OR-5: unequivocal increase). Best RECIST response categories of complete response (CR) or partial response (PR), stable disease (SD), and progression of disease (PD) were compared to best OR response categories (OR-0/1, OR-2/3/4, and OR-5, respectively). Time to treatment failure (TTF) and overall survival (OS) for each category was calculated using Kaplan-Meier methodology. Results: Ninety-one patients were reviewed. Best response based on RECIST v1.1 was CR for 4 patients (4%), PR for 38 patients (42%), SD for 44 patients (48%), and PD for 5 patients (6%). Using OR-categories, 1 patient (1%) was categorized as OR-0, 46 (51%) as OR-1, 34 (37%) OR-2/3/4, and 10 (11%) OR-5. Concordance between the three response categories across RECIST (CR or PR; SD; PD) and OR-RADS (0-1; 2/3/4; 5) was 73.6%. The majority of discordant cases (50%, n=12/24) were patients with SD by RECIST but OR-1 using OR categories. Median TTF was similar between RECIST and OR categories: RECIST CR/PR: 21.8, SD: 6.9, and PD: 1.0 months (p<0.0001) and OR-0/1: 21.5, OR-2/3/4: 7.0, and OR-5 1.1 (p<0.0001). Median OS was similar between RECIST and OR-categories: RECIST CR/PR: 42.6, SD: 9.9, and PD: 8.2 months (p=0.005) and OR-0/1: 42.6, OR-2/3/4: 13.6, and OR-5 7.1 (p<0.0001). Conclusions: There was high concordance between RECIST and OR-categories. This study provides preliminary evidence for the use of standardized OR categories to identify real world responses, with outcomes similar to RECIST response categories. Use of OR can improve communication with patients and oncologists and allow for standardized data extraction of radiologic response for real-world studies.