Evaluating RECIST criteria in resource-limited settings: Guatemala experience.

e23115 Background: RECIST criteria were published in 2000 and updated in 2009 to RECIST 1.1, being the gold standard for tumor evaluation in clinical trials and cancer care. However, in middle-income countries like Guatemala, there are still challenges in implementing them, which leads thousands of people diagnosed with cancer to face health inequalities concerning their clinical follow-up and decisions that directly influence their treatment and life expectancy. This study seeks to evaluate the use of RECIST 1.1 in a Regional Hospital in Guatemala and explore the obstacles for its use. Methods: This is an observational retrospective study conducted from January to December 2023. It involved patients diagnosed with cancer at the Western Regional Hospital who had undergone chemotherapy and/or radiation therapy. The patients were evaluated using computed tomography (CT) based on RECIST 1.1 criteria. Clinical and pathological information was gathered from their medical records. All cases included in the study were required to have CT scans conducted both before and after treatment, as mandated by their attending physicians for response evaluation. Results: A total of 200 cases were screened for the study. Among these, 148 cases (74%) had measurable disease. However, 52 cases were excluded due to incomplete medical records and/or lost CT images. Out of the remaining cases, 60 (40.54%) were evaluated using the RECIST criteria, while 88 cases were not assessed according to RECIST. Only 40% of the radiologists applied the RECIST 1.1 criteria; the remaining 60% continued to use the TNM staging system. Our findings indicated that most of the cases assessed were related to liver (28%), breast (25%), lung (23%), gastric (15%) and cervical (9%) cancers. During the research period, the hospital counted with 2 graduated radiologists and 6 residents, but only the oncologist and the director of the radiology department at the Western Regional Hospital were familiar with the RECIST criteria. Other specialties, such as surgery, internal medicine, and gynecology, were unaware of these criteria for tumor evaluation. Additionally, there is no dedicated record-keeping system, which makes it difficult for doctors to effectively track each patient. This results in incomplete medical records and lost test results, including imaging. Conclusions: The findings in this study highlight the need to train radiologists to apply RECIST 1.1. criteria and the implementation of a medical imaging storage system, to avoid inaccurate tumor evaluation that can impact the treatment outcomes of cancer patients in Guatemala. Patients evaluated with RECIST 1.1. Age Group Cases (%) 35 - 40 2 (4%) 41 - 45 5 (8%) 46 - 50 11 (18%) 51 - 55 9 (15%) 56 - 60 8 (13%) 61 - 65 9 (15%) 66 - 70 5 (8%) 71 - 75 3 (5%) 76 - 80 4 (7%) 81 - 85 4 (7%) Gender Female 38 (63%) Male 22 (37%) Cancer Type Cervical 5 (9%) Breast 15 (25%) Lung 14 (23%) Liver 17 (28%) Stomach 9 (15%) RECIST PD 21 (35%) SD 33 (55%) PR 4 (7%) CR 2 (3%)