Limitations with the response evaluation criteria in solid tumors (RECIST) guidance in disseminated pediatric malignancy

Background. Response evaluation criteria in solid tumors (RECIST) guidelines were published in 2000 to evaluate response to treatment in solid tumors. These have Sought to unify response assessment, and the new guidelines extend beyond lesion assessment to address modern imaging strategies. The RECIST guidelines, however, become complex and problematic when used to evaluate metastatic disease. Methods. Ten consecutive oncology cases representative of tumors common to our pediatric practice were selected. All cases were evaluated at initial presentation and follow-up. The RECIST criteria were retrospectively applied in each case. A standardized evaluation form was used. Results. The age range of the patients included in the study was 1 month to 16 years, with a mean age of 3.9 years. A range Of tumor responses was identified: partial response (n = 6), stable disease (n = 2), and progressive disease (n = 2). Two of these responses were likely incorrect. Tumor bulk was underestimated i the axial plane, many lesions were either calcified and UnmeaSUrable, or despite being well-defined were too small to be measurable under the strict RECIST guidance. Conclusion. In highlighting specific problems with disseminated pediatric tumors, we emphasize the pressing need for debate regarding the application of RECIST in pediatric oncology and encourage the development of a pediatric radiology oncology group to collaborate in future modifications of the RECIST guidance.