30. Paediatric malignancies - The GEC-ESTRO Handbook of Brachytherapy

Paediatric malignancies

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THE GEC ESTRO HANDBOOK OF BRACHYTHERAPY | Part II Clinical Practice Version 1 - 01/09/2023

30 Paediatric malignancies

Cyrus Chargari, Petra Kroon, Bradley R. Pieters

1. Summary 2. Introduction

3 3 4 4 5 5 6 7

9. Treatment planning

10 11 12 12 13 13 14

10. Dose, dose rate and fractionation

3. Anatomical topography

11. Monitoring

4. Pathology 5. Work up

12. Results

13. Adverse Side Effects

6. Indications and contra-indications

14. Key messages 15. References

7. Target Volume 8. Technique

1. SUMMARY

Brachytherapy is a major tool for treatment of paediatric soft tissue tumours, as part of a multimodal approach. It allows dose escalation to the residual tumour while minimizing organs at risk dose exposure. Main indications are sarcoma of the head and neck area, urogenital tract, limbs and trunk. There are increasing data suggesting that the integration of image-guided brachytherapy will allow for more treatment personalization. Most of the clinical evidence comes from low-dose rate and pulsed-dose rate brachytherapy, but use of high-dose rate brachytherapy is developing, with retrospective series suggesting satisfactory efficacy and toxicity profile. Due to the rarity of paediatric cancer and the difficulty to acquire expertise in these treatments, one prerequisite for paediatric brachytherapy treatments is that the team is familiar with adult brachytherapy procedures. The indications and details for the techniques to be applied in paediatric RMS are mainly derived from the respective chapters in adults, with specific adaptation to children. Centralization to high volume centres is recommended.

2. INTRODUCTION

severe side effects associated with external beam radiotherapy when delivered in very young patients. The dosimetric advantages of BT are unequalled in terms of organs at risk sparing capacity. This superiority of BT over other irradiation modalities is particularly relevant to avoid irradiation of bone structures, especially to growth cartilages. It is also an excellent irradiation modality to perform focal dose escalation. In addition, the integral dose to the patient body is low, potentially minimizing the risk of second malignancy that is a significant concern among very young patients treated with ionizing radiation [2,10). Due to the rarity of paediatric cancer and the difficulty to acquire expertise in these treatments, one prerequisite for paediatric BT treatments is that the team is familiar with adult BT procedures. These include medical as well as paramedical expertise. In addition, it is recommended that paediatric cases are referred to expert centres, to increase patient volume and therefore quality of treatments through a high level of expertise [9, 33]. Few centres have expertise for paediatric BT worldwide and most of the knowledge in this setting comes from a few specialist centres, with retrospective experience mainly based on 2D-guided low-dose rate (LDR) BT procedures. Over the past decade, the developments of stepping source technology and 3D-image guidance concepts have been applied to paediatric BT procedures, enabling an increase in

The incidence of paediatric malignancies is low, with an annual frequency of approximately 15 per 100,000 children up to 15 years. It is however a major cause of death among children. Overall, the most frequent paediatric cancers are leukaemia, brain, and central nervous system tumours, and lymphoma. Altogether, these tumours account for approximately 65 % of paediatric tumours. Other tumour sites are less frequent and mainly represented by bone tumours (5%), soft tissue tumours (7%), neuroblastoma (8%), nephroblastoma (8%), and germ cell tumours (4%). There have been significant improvements in survival for paediatric tumours, in parallel with the development of multimodal strategies including active chemotherapy regimens. It is estimated that the probability of 5-year survival was 80-85% among children and adolescents diagnosed with cancer and treated in the 2010-2016 [32, 34, 50, 51]. Local treatments have a major role in the patient’s cure probability. Their impact in terms of long-term morbidity is however to be considered [55]. Together with surgery and external beam radiotherapy, brachytherapy (BT) has potentially a major role in patient treatment, especially in the context of organ-sparing strategies, to avoid mutilating surgery and also the long-term