Table 3. Open in new tab Consensus-Based...

Consensus statements and definitions	Resistance	Rebound	Recurrence regrowth
Definitions and statements apply to all pediatric low-grade glioma molecular and pathology subtypes. (ie, NF1/BRAF^V600E/fusion BRAF, pilocytic astrocytomas, gangliogliomas, etc.)
Definitions and statements apply to all RAS/MAPK inhibitors.
Recommend scan sequences and slice thickness plus interpretation as per RAPNO pediatric low-grade glioma criteria (RAPNO pLGG) Note if tumor has cystic and solid components follow the detailed guidance on cystic disease as recommended by RAPNO pLGG.¹⁷
Timing in relation to treatment	Resistance is growth while on systemic treatment eg, MAPK inhibitor therapy.	Rebound growth of an existing lesion usually within 3 months of cessation of systemic (MAPK inhibitor) therapy. Regrowth ≥ 6 months after stopping treatment is NOT rebound.	Recurrence regrowth occurs off treatment and is the term to be used for any regrowth ≥ 6 months after stopping treatment.
Radiological criteria as per RAPNO pLGG. (Cross-sectional change)	≥25% of growth or a new (metastatic) lesion, ideally confirmed with a second scan, unless clinically inappropriate. Stable disease should NOT be called resistance.	≥25% of growth of an existing lesion, ideally confirmed with a second scan unless clinically inappropriate.	≥25% of growth or a new (metastatic) lesion, ideally confirmed with a second scan, unless clinically inappropriate.
MRI scan to be used for comparison. (To calculate percentage regrowth)	Best recorded MRI response while on MAPK inhibitor therapy.	The last MRI scan was while on MAPK inhibitor therapy.	The last MRI scan was while on MAPK inhibitor therapy.
New (Metastatic) lesion	A new (metastatic) lesion occurring on treatment is regarded as resistance regrowth.	New metastatic lesions are NOT considered rebound regrowth.	A new (metastatic) lesion occurring off treatment is regarded as recurrence regrowth.

Consensus statements and definitions

Resistance

Rebound

Recurrence regrowth

Definitions and statements apply to all pediatric low-grade glioma molecular and pathology subtypes.
(ie, NF1/BRAF^V600E/fusion BRAF, pilocytic astrocytomas, gangliogliomas, etc.)

Definitions and statements apply to all RAS/MAPK inhibitors.

Recommend scan sequences and slice thickness plus interpretation as per RAPNO pediatric low-grade glioma criteria (RAPNO pLGG)
Note if tumor has cystic and solid components follow the detailed guidance on cystic disease as recommended by RAPNO pLGG.¹⁷

Timing in relation to treatment

Resistance is growth while on systemic treatment eg, MAPK inhibitor therapy.

Rebound growth of an existing lesion usually within 3 months of cessation of systemic (MAPK inhibitor) therapy.
Regrowth ≥ 6 months after stopping treatment is NOT rebound.

Recurrence regrowth occurs off treatment and is the term to be used for any regrowth ≥ 6 months after stopping treatment.

Radiological criteria as per RAPNO pLGG.
(Cross-sectional change)

≥25% of growth or a new (metastatic) lesion, ideally confirmed with a second scan, unless clinically inappropriate. Stable disease should NOT be called resistance.

≥25% of growth of an existing lesion, ideally confirmed with a second scan unless clinically inappropriate.

≥25% of growth or a new (metastatic) lesion, ideally confirmed with a second scan, unless clinically inappropriate.

MRI scan to be used for comparison.
(To calculate percentage regrowth)

Best recorded MRI response while on MAPK inhibitor therapy.

The last MRI scan was while on MAPK inhibitor therapy.

New (Metastatic) lesion

A new (metastatic) lesion occurring on treatment is regarded as resistance regrowth.

New metastatic lesions are NOT considered rebound regrowth.

A new (metastatic) lesion occurring off treatment is regarded as recurrence regrowth.

Consensus statements and definitions	Resistance	Rebound	Recurrence regrowth
Definitions and statements apply to all pediatric low-grade glioma molecular and pathology subtypes. (ie, NF1/BRAF^V600E/fusion BRAF, pilocytic astrocytomas, gangliogliomas, etc.)
Definitions and statements apply to all RAS/MAPK inhibitors.
Recommend scan sequences and slice thickness plus interpretation as per RAPNO pediatric low-grade glioma criteria (RAPNO pLGG) Note if tumor has cystic and solid components follow the detailed guidance on cystic disease as recommended by RAPNO pLGG.¹⁷
Timing in relation to treatment	Resistance is growth while on systemic treatment eg, MAPK inhibitor therapy.	Rebound growth of an existing lesion usually within 3 months of cessation of systemic (MAPK inhibitor) therapy. Regrowth ≥ 6 months after stopping treatment is NOT rebound.	Recurrence regrowth occurs off treatment and is the term to be used for any regrowth ≥ 6 months after stopping treatment.
Radiological criteria as per RAPNO pLGG. (Cross-sectional change)	≥25% of growth or a new (metastatic) lesion, ideally confirmed with a second scan, unless clinically inappropriate. Stable disease should NOT be called resistance.	≥25% of growth of an existing lesion, ideally confirmed with a second scan unless clinically inappropriate.	≥25% of growth or a new (metastatic) lesion, ideally confirmed with a second scan, unless clinically inappropriate.
MRI scan to be used for comparison. (To calculate percentage regrowth)	Best recorded MRI response while on MAPK inhibitor therapy.	The last MRI scan was while on MAPK inhibitor therapy.	The last MRI scan was while on MAPK inhibitor therapy.
New (Metastatic) lesion	A new (metastatic) lesion occurring on treatment is regarded as resistance regrowth.	New metastatic lesions are NOT considered rebound regrowth.	A new (metastatic) lesion occurring off treatment is regarded as recurrence regrowth.

Table 3.

Open in new tab

Consensus-Based Definitions for Resistance, Rebound, and Recurrence Regrowth Patterns in Pediatric Low-Grade Glioma: International Pediatric Low-Grade Glioma Coalition

Consensus statements and definitions	Resistance	Rebound	Recurrence regrowth
Definitions and statements apply to all pediatric low-grade glioma molecular and pathology subtypes. (ie, NF1/BRAF^V600E/fusion BRAF, pilocytic astrocytomas, gangliogliomas, etc.)
Definitions and statements apply to all RAS/MAPK inhibitors.
Recommend scan sequences and slice thickness plus interpretation as per RAPNO pediatric low-grade glioma criteria (RAPNO pLGG) Note if tumor has cystic and solid components follow the detailed guidance on cystic disease as recommended by RAPNO pLGG.¹⁷
Timing in relation to treatment	Resistance is growth while on systemic treatment eg, MAPK inhibitor therapy.	Rebound growth of an existing lesion usually within 3 months of cessation of systemic (MAPK inhibitor) therapy. Regrowth ≥ 6 months after stopping treatment is NOT rebound.	Recurrence regrowth occurs off treatment and is the term to be used for any regrowth ≥ 6 months after stopping treatment.
Radiological criteria as per RAPNO pLGG. (Cross-sectional change)	≥25% of growth or a new (metastatic) lesion, ideally confirmed with a second scan, unless clinically inappropriate. Stable disease should NOT be called resistance.	≥25% of growth of an existing lesion, ideally confirmed with a second scan unless clinically inappropriate.	≥25% of growth or a new (metastatic) lesion, ideally confirmed with a second scan, unless clinically inappropriate.
MRI scan to be used for comparison. (To calculate percentage regrowth)	Best recorded MRI response while on MAPK inhibitor therapy.	The last MRI scan was while on MAPK inhibitor therapy.	The last MRI scan was while on MAPK inhibitor therapy.
New (Metastatic) lesion	A new (metastatic) lesion occurring on treatment is regarded as resistance regrowth.	New metastatic lesions are NOT considered rebound regrowth.	A new (metastatic) lesion occurring off treatment is regarded as recurrence regrowth.

Consensus statements and definitions	Resistance	Rebound	Recurrence regrowth
Definitions and statements apply to all pediatric low-grade glioma molecular and pathology subtypes. (ie, NF1/BRAF^V600E/fusion BRAF, pilocytic astrocytomas, gangliogliomas, etc.)
Definitions and statements apply to all RAS/MAPK inhibitors.
Recommend scan sequences and slice thickness plus interpretation as per RAPNO pediatric low-grade glioma criteria (RAPNO pLGG) Note if tumor has cystic and solid components follow the detailed guidance on cystic disease as recommended by RAPNO pLGG.¹⁷
Timing in relation to treatment	Resistance is growth while on systemic treatment eg, MAPK inhibitor therapy.	Rebound growth of an existing lesion usually within 3 months of cessation of systemic (MAPK inhibitor) therapy. Regrowth ≥ 6 months after stopping treatment is NOT rebound.	Recurrence regrowth occurs off treatment and is the term to be used for any regrowth ≥ 6 months after stopping treatment.
Radiological criteria as per RAPNO pLGG. (Cross-sectional change)	≥25% of growth or a new (metastatic) lesion, ideally confirmed with a second scan, unless clinically inappropriate. Stable disease should NOT be called resistance.	≥25% of growth of an existing lesion, ideally confirmed with a second scan unless clinically inappropriate.	≥25% of growth or a new (metastatic) lesion, ideally confirmed with a second scan, unless clinically inappropriate.
MRI scan to be used for comparison. (To calculate percentage regrowth)	Best recorded MRI response while on MAPK inhibitor therapy.	The last MRI scan was while on MAPK inhibitor therapy.	The last MRI scan was while on MAPK inhibitor therapy.
New (Metastatic) lesion	A new (metastatic) lesion occurring on treatment is regarded as resistance regrowth.	New metastatic lesions are NOT considered rebound regrowth.	A new (metastatic) lesion occurring off treatment is regarded as recurrence regrowth.

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