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Rhabdomyosarcoma — IRS Group

Intergroup Rhabdomyosarcoma Study post-surgical grouping.

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1 What is the Rhabdomyosarcoma — IRS Group?

The Rhabdomyosarcoma — IRS Group is a oncology scoring tool used in paediatric practice. Intergroup Rhabdomyosarcoma Study post-surgical grouping. It scores 1 criteria and interprets the total across 4 bands, so the number always arrives with the severity it implies rather than on its own. In PediAid each criterion is shown as a labelled option with the weight it carries, so the total can be checked rather than taken on trust.

2 When to use it

  • Grading severity at the bedside in oncology
  • Recording an objective severity band in the case notes
  • Deciding when a total crosses the threshold for escalation
  • Re-scoring to track whether a child is improving or deteriorating
  • Checking the exact criteria of a score used infrequently

3 Formula & method

The score sums 1 criteria: Post-surgical extent. Totals are then banded: 1 stage or more - Group I: group I - completely resected. Best prognosis; chemotherapy without radiotherapy in favourable subsets; 2 stage or more - Group II: group II - microscopic residual or nodal disease. Chemotherapy plus radiotherapy; 3 stage or more - Group III: group III - gross residual disease (the largest group). Chemotherapy plus radiotherapy, with delayed surgery when feasible; 4 stage or more - Group IV: group IV - metastatic disease. Poor prognosis; intensified multimodal therapy.
  • Overall risk also depends on histology (embryonal vs alveolar / FOXO1 fusion status), site (favourable vs unfavourable) and tumour size/age.
  • Source: Crist W et al. The Third Intergroup Rhabdomyosarcoma Study. J Clin Oncol 1995;13:610-30.
  • Source: Gupta S, Aitken JF, Bartels U et al. Paediatric cancer stage in population-based cancer registries: the Toronto consensus principles and guidelines. Lancet Oncol 2016;17:e163-72.

4 Frequently asked questions

How many criteria does the Rhabdomyosarcoma — IRS Group use?

1. They are Post-surgical extent.

What do the bands of the Rhabdomyosarcoma — IRS Group mean?

The total is interpreted as: 1 stage or more - Group I: group I - completely resected. Best prognosis; chemotherapy without radiotherapy in favourable subsets; 2 stage or more - Group II: group II - microscopic residual or nodal disease. Chemotherapy plus radiotherapy; 3 stage or more - Group III: group III - gross residual disease (the largest group). Chemotherapy plus radiotherapy, with delayed surgery when feasible; 4 stage or more - Group IV: group IV - metastatic disease. Poor prognosis; intensified multimodal therapy.

Does the score replace clinical judgement?

No. It is a structured way to record and communicate severity. A clinician concerned about a child should act on that concern regardless of the total.

Where does this score come from?

Overall risk also depends on histology (embryonal vs alveolar / FOXO1 fusion status), site (favourable vs unfavourable) and tumour size/age.

Does it work offline?

Yes. Score definitions are bundled with the PediAid app, so the score computes without a connection.

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For qualified clinicians. This page and the PediAid app are a clinical aid only. Calculations and reference data must be verified against the patient's clinical context, the source guideline and your local protocols before any treatment decision is made.