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

Abstract

Malignant renal tumours represent 5% of childhood cancers and include types with likely different aetiology: Wilms tumour (WT), rhabdoid renal tumour, kidney sarcomas and renal carcinomas. WT is the most common renal tumour in children, previously shown to vary internationally and with ethnicity. Using the comprehensive database of the International Incidence of Childhood Cancer study (IICC), we analysed global variations and time trends in incidence of renal tumour types in children (age 0-14 years) and adolescents (age 15-19 years). The results were presented by 14 world regions, and five ethnic groups in the US. We included 15 320 renal tumours in children and 800 in adolescents reported to the 163 contributing registries during 2001-2010. In children, age-standardised incidence rate (ASR) of renal tumours was 8.3 per million (95% confidence interval, CI = 8.1, 8.4); it was the highest in North America and Europe (9-10 per million) and the lowest in most Asian regions (4-5 per million). In the US, Blacks had the highest ASR (10.9 per million, 95% CI = 10.2, 11.6) and Asian and Pacific Islanders the lowest (4.4 per million, 95% CI = 3.6, 5.1). In adolescents, age-specific incidence rate of renal tumours was 1.4 per million (95% CI = 1.3, 1.5). WT accounted for over 90% of all renal tumours in each age from 1 to 7 years and the proportion of renal carcinomas increased gradually with age. From 1996 to 2010, incidence remained mostly stable for WT (average annual percent change, AAPC = 0.1) and increased for renal carcinomas in children (AAPC = 3.7) and adolescents (AAPC = 3.2). Our findings warrant further monitoring.

Keywords: Wilms tumour; cancer epidemiology; childhood renal tumour; paediatric kidney cancer; population-based cancer registry study.

FIGURE 1

Age‐standardised incidence rates (ASRs) of renal tumours in children aged 0 to 14 years by world region and ethnicity, 2001 to 2010 (n = 15 320). Source: International Incidence of Childhood Cancer, volume 3. ²³ Tumour groups are defined in Table S1. The registries’ contribution to the analyses is shown in Table S2. ASR, age‐standardised incidence rate; Unspecified, unspecified malignant renal tumours

FIGURE 2

Age‐specific incidence of renal tumours, all world regions combined, 2001 to 2010. Source: International Incidence of Childhood Cancer, volume 3. ²³ Tumour groups are defined in Table S1. The registries’ contribution to the analyses is shown in Table S2. A, Wilms tumour (n = 13 838) by sex and laterality* (n = 6396). B, Rhabdoid renal tumour (n = 327) and kidney sarcomas (n = 431). C, Renal carcinomas (n = 1009). *Only the registries providing information on the laterality for at least 95% Wilms tumour cases are included.

FIGURE 3

Time trends in incidence of renal tumours, all world regions combined, 1996 to 2010 (n = 11 170). Source: International Incidence of Childhood Cancer, volume 3. ²³ Tumour groups are defined in Table S1. The registries’ contribution to the analyses is shown in Table S2. ASR, age‐standardised incidence rate; Unspecified, Unspecified malignant renal tumours; Solid line: predicted ASR; Dotted line: observed ASR. Scale on the left axis: ASR for Wilms tumour; Scale on the right axis: ASR for renal tumours other than Wilms tumour

FIGURE 4

Age‐standardised incidence rates (ASRs) of Wilms tumour and other non‐epithelial renal tumours in children aged 0 to 14 years in the selected registries in IICC‐1, ²¹ IICC‐2 ²² and IICC‐3. ²³ The selected registries are those that contributed data for similarly defined populations to all three International Incidence of Childhood Cancer (IICC) volumes ²¹ , ²² , ²³ and reported 15 or more renal tumour cases in each volume. ASR, age‐standardised incidence rate. *Data from regional registries were pooled (India: Bangalore and Mumbai, Japan: Miyagi and Osaka, Philippines: Manila and Rizal, USA: SEER9, Los Angeles and New York State). 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