Risk factors
Risk group classification in neuroblastoma is an important step that determines treatment and prognosis.
There is now an International Neuroblastoma Risk Group Classification System that combines 7 risk factors to place patients into low, intermediate or high risk groups. Treatment is planned based on risk group. In the medical evidence, the risk group may be clear, or the risk group may be inferred from the treatment the child is having. Information about the factors used to place children in risk groups is provided. Information is provided to aid understanding of terms used in medical evidence and should not be used to classify individual cases in to risk groups.
The risk factors used to determine the appropriate risk group are -:
- Stage of disease - as defined by the INRGSS, generally those with L1 have a good prognosis and those with metastatic disease (M) have a poorer prognosis. There is a special group of those under the age of one with low level metastatic disease (MS) who have a good prognosis. The stages may be described by the older INSS as stage 1-4 or 4S.
- Age of the child - age is a factor that affects outcome, younger children tend to do better no matter what treatment they have and older children tend to do worse no matter what treatment they have.
- Features of the tumour -:
- Genetic markers - present in the tumour including MYCN amplification, ploidy and 11q deletion.
- Histological category - there are various sub-types of neuroblastoma which have particular histological appearances and this can be relevant to prognosis.
- Grade of tumour - Neuroblastomas are graded on the basis of “how malignant” the cells appear.
The table below shows how these known risk factors can be used to assign all patients as low, intermediate or high risk. There is also a very low risk group.
The table also shows how the risk factors act with one another using INRGSS to classify children into risk groups using various factors.
Note: In the table below:
The acronym (GN) refers to Ganglioneuroma
The acronym (GNB) refers to Ganglioneuroblastoma
| INRGSS stage | Age (in months) | Histologic category | Grade of tumour | MYCN (genetic abnormality of the tumour cells) |
11q aberration (genetic abnormality of the tumour cells) |
Ploidy | Pre-treatment risk group |
|---|---|---|---|---|---|---|---|
L1/L2 |
N/A |
GN maturing; GNB intermixed |
N/A |
N/A |
N/A |
N/A |
Very low |
L1 |
Less than 18 months |
Any except GN maturing and GNB intermixed |
N/A |
No amplification |
N/A |
N/A |
Very low |
L1 |
Less than 18 months |
Any except GN maturing and GNB intermixed |
N/A |
Amplification |
N/A |
N/A |
High |
L2 |
Less than 18 months |
Any except GN maturing and GNB intermixed |
N/A |
No amplification |
No |
N/A |
Low |
L2 |
Less than 18 months |
Any except GN maturing and GNB intermixed |
N/A |
No amplification |
Yes |
N/A |
Intermediate |
L2 |
Over 18 months |
GNB nodular; neuroblastoma |
Differentiating |
No amplification |
No |
N/A |
Low |
L2 |
Over 18 months |
GNB nodular; neuroblastoma |
Differentiating |
No amplification |
Yes |
N/A |
Intermediate |
L2 |
Over 18 months |
GNB nodular; neuroblastoma |
Poorly differentiated or undifferentiated |
N/A |
N/A |
N/A |
Intermediate |
L2 |
Over 18 months |
GNB nodular; neuroblastoma |
N/A |
Amplification |
N/A |
N/A |
High |
M |
Less than 18 months |
N/A |
N/A |
No amplification |
N/A |
Hyperdiploid |
Low |
M |
Less than 12 months |
N/A |
N/A |
No amplification |
N/A |
Diploid |
Intermediate |
M |
12 to 18 months |
N/A |
N/A |
No amplification |
N/A |
Diploid |
Intermediate |
M |
Less than 18 months |
N/A |
N/A |
Amplification |
N/A |
N/A |
High |
M |
Over 18 months |
N/A |
N/A |
N/A |
N/A |
N/A |
High |
MS |
N/A |
N/A |
N/A |
N/A |
No |
N/A |
Very low |
MS |
N/A |
N/A |
N/A |
No amplification |
Yes |
N/A |
High |
MS |
Over 18 months |
N/A |
N/A |
Amplification |
N/A |
N/A |
High |
Reproduced from Cohn et al JCO 27(2): 295, 2009
