Score lesions against valid mediastinal and liver references, then synthesize longitudinal response; never equate a bare 4 or 5 with progression or a treatment order.
{
"categories": [
{
"outcome_code": "1",
"visual_definition": "no_abnormal_FDG_uptake_above_background"
},
{
"outcome_code": "2",
"visual_definition": "lesion_uptake_at_or_below_mediastinal_blood_pool"
},
{
"outcome_code": "3",
"visual_definition": "lesion_uptake_above_mediastinum_and_at_or_below_liver"
},
{
"outcome_code": "4",
"visual_definition": "lesion_uptake_moderately_above_liver"
},
{
"outcome_code": "5",
"visual_definition": "lesion_uptake_markedly_above_liver_or_new_site_consistent_with_lymphoma"
}
],
"applicability": {
"intended_use": "Visual FDG-PET response assessment for FDG-avid lymphoma within a declared Lugano or protocol-specific framework.",
"classification_units": [
"one_lesion_at_one_timepoint",
"patient_level_response_after_longitudinal_synthesis"
],
"required_context": [
"lymphoma_subtype_and_baseline_FDG_avidity",
"baseline_or_nadir_comparator",
"interim_or_end_of_treatment_timepoint",
"treatment_and_scan_timing",
"technical_comparability",
"valid_mediastinal_and_liver_references",
"all_lesions_and_new_sites"
],
"outside_scope": [
"non_FDG_avid_lymphoma_without_an_explicit_protocol",
"generic_solid_tumor_response",
"treatment_selection_from_score_alone",
"standalone_histologic_diagnosis",
"individual_outcome_probability"
]
},
"visual_scoring_protocol": {
"comparison_order": "Compare each relevant focus first with mediastinal blood pool and then with normal liver uptake on the same examination.",
"score_1": "No abnormal uptake attributable to lymphoma.",
"score_2": "Uptake no greater than mediastinal blood pool.",
"score_3": "Uptake greater than mediastinal blood pool but no greater than liver.",
"score_4": "Uptake moderately greater than liver.",
"score_5": "Uptake markedly greater than liver and/or one or more new FDG-avid sites whose pattern is consistent with lymphoma.",
"X_qualifier": "Use X for a new focus considered unlikely to represent lymphoma. X is a descriptive qualifier, not a sixth ordinal score and not progression.",
"highest_lesion_rule": "For patient-level reporting, identify the most metabolically active relevant lesion and preserve lesion-level heterogeneity; do not average scores."
},
"reference_region_and_quality_gate": {
"mediastinum": "Use a reproducible mediastinal blood-pool reference that avoids focal disease and major artifact.",
"liver": "Use normal liver parenchyma away from focal disease, artifact or abnormal diffuse uptake; record when liver uptake is unsuitable as a reference.",
"comparability": "Review uptake time, administered activity, glucose, scanner/reconstruction, motion, attenuation correction and treatment interval before interpreting longitudinal change.",
"confounders": [
"infection_or_inflammation",
"recent_surgery_or_radiotherapy",
"growth_factor_or_marow_activation",
"brown_fat_or_muscle_activity",
"physiologic_or_excreted_tracer",
"thymic_rebound",
"second_malignancy"
],
"indeterminate_behavior": "When reference regions or a new focus are unreliable, return an indeterminate or X-qualified interpretation with the reason instead of forcing a score or progression state."
},
"Lugano_response_synthesis": {
"complete_metabolic_response_CMR": "Scores 1, 2 or 3 in nodal and extranodal sites, with or without a residual mass, constitute complete metabolic response under standard Lugano interpretation.",
"partial_metabolic_response_PMR": "Score 4 or 5 with uptake reduced from baseline and no qualifying new progressive disease. At interim this represents responding disease; at end of treatment it represents residual metabolic disease.",
"no_metabolic_response_NMR": "Score 4 or 5 with no significant change in uptake from baseline or nadir, after accounting for technical comparability.",
"progressive_metabolic_disease_PMD": "Score 4 or 5 with increased intensity or extent from baseline or nadir and/or a new FDG-avid focus whose pattern is consistent with lymphoma.",
"no_score_only_progression": "A score of 4 or 5 without longitudinal direction and new-lesion adjudication cannot by itself distinguish PMR, NMR and PMD."
},
"decisive_boundaries": {
"score_2_to_3": "Uptake equal to mediastinum is 2; uptake above mediastinum but no greater than liver is 3.",
"score_3_to_4": "Uptake equal to liver remains 3; uptake moderately above liver is 4.",
"score_4_to_5": "Markedly above liver or a new lymphoma-consistent site supports 5. Preserve the qualitative basis rather than inventing a universal SUV threshold.",
"score_5_new_site_versus_X": "A new focus consistent with lymphoma can support 5 and PMD; uptake unlikely to be lymphoma is X and requires its alternate explanation.",
"interim_versus_end_of_treatment": "The same score 4 or 5 with decreased uptake means responding disease at interim but residual metabolic disease at end of treatment."
},
"protocol_and_version_boundaries": {
"score_3": "Standard Lugano treats score 3 as CMR, but a trial designed for treatment de-escalation may predeclare a stricter positive cutoff. Name the protocol and never silently change the standard definition.",
"proposed_2025_clarifications": "A proposed score-5 threshold based on at least twice maximum liver uptake and proposed 5a/5b subdivision remain revision proposals, not replacements for the current standard unless an adopted protocol explicitly says so.",
"immunotherapy": "When an immunotherapy protocol invokes LYRIC or another immune-response framework, apply its indeterminate-response and confirmation rules separately rather than relabeling a Deauville score.",
"RECIST_or_PERCIST": "RECIST and PERCIST use different measurement and synthesis rules; no numeric crosswalk to Deauville is valid."
},
"management_boundary": {
"no_autonomous_change": "Do not continue, de-escalate, escalate, biopsy or stop treatment from the bare Deauville score alone.",
"required_decision_context": [
"histology_and_treatment_protocol",
"interim_or_end_of_treatment_timepoint",
"baseline_change_and_distribution",
"clinical_status_and_laboratory_data",
"technical_quality_and_confounders",
"multidisciplinary_review"
],
"discordant_or_new_focus": "When a new or discordant focus could be inflammatory, infectious or another malignancy, recommend targeted correlation, follow-up or tissue sampling according to whether the result would change care."
},
"risk_interpretation": {
"qualitative_role": "The response state has cohort-level prognostic associations, but scores 1-5 are not calibrated malignancy probabilities or individualized progression-free-survival estimates.",
"protocol_dependence": "Outcome meaning varies by lymphoma subtype, line of therapy, interim versus end-of-treatment timing, treatment adaptation and score cutoff.",
"prohibited_inferences": [
"score_1_or_2_guarantees_cure",
"score_3_is_always_positive",
"score_4_or_5_equals_progression",
"score_5_proves_lymphoma_in_a_new_focus",
"patient_specific_survival_percentage"
]
},
"agent_output_contract": [
"Return lymphoma subtype, baseline avidity, treatment, protocol and response timepoint.",
"Return technical comparability and validity of mediastinal and liver references.",
"Return each decisive lesion, reference comparison, lesion score and new-site adjudication.",
"Return the patient-level highest score and longitudinal Lugano state CMR, PMR, NMR or PMD with explicit reasoning.",
"Separate the score, response state, protocol-specific positivity, treatment recommendation and prognosis."
],
"missing_input_behavior": [
"Without baseline or nadir comparison, return the current lesion score but withhold PMR, NMR or PMD synthesis when longitudinal direction is required.",
"Without a valid liver or mediastinal reference, describe uptake and technical limitations rather than forcing the adjacent score.",
"Without a declared timepoint, do not call decreased score 4 or 5 interim response versus end-of-treatment residual disease.",
"For a new uncertain focus, use X or an indeterminate explanation and seek targeted correlation instead of automatic score 5 progression."
],
"supporting_sources": [
{
"role": "original_scale",
"citation": "Meignan et al. Leuk Lymphoma. 2009;50:1257-1260",
"doi": "10.1080/10428190903040048"
},
{
"role": "Lugano_standard",
"citation": "Cheson et al. J Clin Oncol. 2014;32:3059-3068",
"doi": "10.1200/JCO.2013.54.8800"
},
{
"role": "operational_consensus",
"citation": "Barrington et al. J Nucl Med. 2023;64:102-108",
"doi": "10.2967/jnumed.122.264124",
"pmcid": "PMC9902846"
},
{
"role": "current_status",
"citation": "Barrington et al. Hematol Oncol. 2025",
"doi": "10.1002/hon.70103"
}
],
"source_locator": "Meignan et al. 2009, DOI 10.1080/10428190903040048, original scale; Cheson et al. 2014, DOI 10.1200/JCO.2013.54.8800, PET response table; Barrington et al. 2023, PMC9902846, PRoLoG technical application; Barrington et al. 2025, DOI 10.1002/hon.70103, current-standard and proposal boundary."
}