Indications and results of diagnostic biopsy in pediatric renal tumors: A retrospective analysis of 317 patients with critical review of SIOP guidelines

Abstract

Objectives According to the Renal Tumor Study Group (RTSG) of the International Society of Paediatric Oncology (SIOP), diagnostic biopsy of renal tumors prior to neoadjuvant chemotherapy is not mandatory unless the presentation is atypical for a Wilms tumor (WT). This study addresses the relevance of this strategy as well as the accuracy and safety of image‐guided needle biopsy. Methods Clinical, radiological, and pathological data from 317 children (141 males/176 females, mean age: 4 years, range, 0–17.6) consecutively treated in one SIOP‐affiliated institution were retrospectively analyzed. Results Presumptive chemotherapy for WT was decided for 182 patients (57% of the cohort), 24 (8%) were operated upfront, and 111 (35%) were biopsied at diagnosis. A non‐WT was confirmed after surgery in 5/182 (3%), 11/24 (46%), and 28/111 (25%), respectively. Age at diagnosis was the most commonly (46%) used criterion to go for biopsy but a nine‐year threshold should be retrospectively considered more relevant. Tumor volumes of clear cell sarcoma of the kidney and WT were significantly higher than those of other tumors (P = 0.002). The agreement between core‐needle biopsy (CNB) and final histology was 99%. No significant morbidity was associated with CNB. Conclusion The use of SIOP criteria to identify patients eligible for presumptive WT neoadjuvant chemotherapy or upfront surgery avoided biopsy in 65% of children and led to a 97% rate of appropriate preoperative chemotherapy. Image‐guided CNB is a safe and accurate diagnostic procedure. The relevance of SIOP biopsy criteria might be improved by using an older age threshold (9 years instead of 6 years) and by adding initial tumor volume.

Incidence of childhood renal tumours: An international population‐based study

“…The selected cases were those classified to the International Classification of Childhood Cancer (ICCC) subgroup VIa in each IICC volume, although the definition of this subgroup differed slightly between the three sources [21][22][23] [Color figure canbe viewed atwileyonlinelibrary.com] may be used in making therapeutic recommendations about the applicable age range for omitting biopsy before preoperative chemotherapy, which has been discussed in European clinical study groups. 38,39 We did not observe temporal trends in the incidence of WT within the period 1996 to 2010, suggesting that environmental factors play a marginal role in the aetiology of this tumour, although the modifiable risk factors for WT are not well understood. Folic acid diet fortification in the USA was suggested as a possible driver of a reduction of the WT incidence.…”

“…Our finding of a 90% majority of WT in the group of all renal tumours from the age of 1 to 7 years, observed in large populations, may be used in making therapeutic recommendations about the applicable age range for omitting biopsy before preoperative chemotherapy, which has been discussed in European clinical study groups 38,39 …”

Comment on: “Indications and results of diagnostic biopsy in pediatric renal tumors: A retrospective analysis of 317 patients with critical review of SIOP guidelines”

“…We read with interest the article by de la Monneraye et al on the experience of the Institut Curie of renal tumor biopsy in children treated according to SIOP protocols over a 22-year period. 1 By presenting the relative proportion of children with non-Wilms tumors who had clinical, radiological, and biochemical features that are considered "atypical" of Wilms tumors (WT), they support a change to an evidence-based approach to biopsy in the SIOP community.…”

“…We read with interest the article by de la Monneraye et al on the experience of the Institut Curie of renal tumor biopsy in children treated according to SIOP protocols over a 22‐year period …”

Reply to comment on: The diagnostic accuracy and clinical utility of pediatric renal tumor biopsy: Report of the UK experience in the SIOP UK WT2001 trial

“…We read the comments from Jackson et al concerning our publication with careful attention and wanted to provide clarifications in order to avoid any misunderstanding. After similarly reading their article published in the same issue, we also wished to comment on that.…”