Radical radiotherapy for paediatric solid tumour metastases: An overview of current European protocols and outcomes of a SIOPE multicenter survey

Abstract

Purpose/objective: About 20% of children with solid tumours (ST) present with distant metastases (DM). Evidence regarding the use of radical radiotherapy of these DM is sparse and open for personal interpretation.The aim of this survey was to review European protocols and to map current practice regarding the irradiation of DM across SIOPE-affiliated countries. Materials/methods: Radiotherapy guidelines for metastatic sites (bone, brain, distant lymph nodes, lung and liver) in eight European protocols for rhabdomyosarcoma, non-rhabdomyosarcoma softtissue sarcoma, Ewing sarcoma, neuroblastoma and renal tumours were reviewed. SIOPE centres irradiating !50 children annually were invited to participate in an online survey. Results: Radiotherapy to at least one metastatic site was recommended in all protocols, except for high-risk neuroblastoma. Per protocol, dose prescription varied per site, and information on delineation and treatment planning/delivery was generally missing.Between July and September 2019, 20/27 centres completed the survey. Around 14% of patients were deemed to have DM from ST at diagnosis, of which half were treated with curative intent. A clear cut-off for a maximum number of DM was not used in half of the centres. Regardless of the tumour type and site, conventional radiotherapy regimens were most commonly used to treat DM. When stereotactic radiotherapy was used, a wide range of fractionation regimens were applied. Conclusion: Current radiotherapy guidelines for DM do not allow a consistent approach in a multicentre setting. Prospective (randomised) trials are needed to define the role of radical irradiation of DM from paediatric ST.

Radical skeletal metastatic site irradiation in high-risk neuroblastoma: systematic review and proposal for a randomised trial

“…Finally, a small study by Sangthawan et al was reviewed; it was not found in our primary literature search but was identified from a prior systematic review [40] . This study evaluated 20 patients who received radiation to residual mIBG-positive sites of disease.…”

Immunohistochemical analyses of paraffin-embedded sections after primary surgery or trimodality treatment in esophageal carcinoma

“…Not surprising, hypoxic tumor subvolumes have been correlated with tumor evasion signatures such as tumoral immune escape, proliferation, mutational status and stemness [23] , [24] , [27] . In general, cancer stem cells represent a tumor subpopulation responsible for tumor metastasis and resistance to radiotherapy, ultimately leading to tumor relapse [28] , [29] , [30] .…”

Dosimetric feasibility of hypofractionation for metastatic bone/bone marrow lesions from paediatric solid tumours

“…A recent survey across leading European paediatric radiotherapy centres unveiled both consistencies and differences regarding the radiotherapy approach with curative intent on metastatic sites, especially regarding patient selection and treatment characteristics [4]. A growing interest in hypofractionation was noticed, but prescription doses and fractionation schedules are currently mainly based on local experience and institutional protocols [4].…”

“…Moreover, in current European paediatric solid tumour protocols, hypofractionation is sporadically recommended [5][6][7][8]. Across the respondents of the survey, an urgent need for consensus on the total and fraction dose per site, age group and disease category was expressed [4].…”