Transcript Limitations of RECIST guidelines

Limitations of RECIST guidelines
Srinivasa R Prasad MD
Associate Professor, Radiology
University of Texas Health Science Center at
San Antonio
RECIST Guidelines
• Response Evaluation Criteria In Solid Tumors
• Assumes spherical growth of round / ovoid tumors
• Uni-dimensional measurement technique
– Less cumbersome, Simple math
• Arbitrary number of measurable lesions
– 5/organ; 10/patient
RECIST Guidelines
• Target lesions: >1cm (Helical); >2cm (Non-helical)
• Measurement on axial images
• Increase in the threshold for classifying response as
disease progression
• Primary modality: CT scan
Limitations of RECIST guidelines
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No criteria for non-solid tumors
No toxicity criteria
Lower rate of disease progression?
Not applicable to Non-Cytotoxic drugs?
Change in Tumor Form:
From Solid to Non-Solid
Limitations of RECIST guidelines
• Tumor morphology
– Confluent, Irregular borders
– Unusual configuration; Circumferential (eg.
mesothelioma)
– Lesion length > 1.5-2 times lesion width
• Discordant results due to RECIST technique
– Uni-dimensional measurement
– Shape changes may confound results
Lesion Confluence and
Relationship to Normal
Anatomical Structures
Unusual Lesion
Configuration
Lesion Morphology: Mesothelioma
Limitations of RECIST guidelines
• Non-spherical, asymmetric tumor growth
• Tumor size: Sub-centimeter tumors
• Choosing representative tumor burden
– Problematic when tumor burden is substantial
– Differential tumor response
Differential tumor
behavior
Pre
Post
Limitations of RECIST guidelines
• Discordant results due to RECIST technique
– Unusual Tumor morphology
• Confluent tumors, Unusual growth pattern
• Lesion length > 2 times lesion width
• Lesions with irregular / infiltrative borders
– Unpredictable Tumor Behavior
• Differential tumor shrinkage/growth
Differential tumor
behavior
Change in Tumor
Form: From
Solid to Non-Solid
Limitations of RECIST guidelines
• Updated imaging technology not considered
– Multiplanar capability
– Automated tumor detection
– 3-D data acquisition: volumetric tumor
measurement
Limitations of RECIST guidelines
• Criteria for tumors treated by Non-drugs?
(eg: Radio-frequency ablation)
• Metabolic and physiological changes
predate tumor size change
Non-Drug treatment of tumors: Response criteria?
Imaging Pitfalls: Scanning
& Visualization Techniques
Future?
WHO-Bidimensional
RECIST-Unidimensional
Volumetric