IARC 60th Anniversary - 19-21 May 2026
Session : 19/05/26 - Posters
Risk of Subsequent Primary Neoplasms After Childhood Cancer: the CRICCS study results
SUNGUC C. 1,2, MAKOHUSOVA M. 1,3, COLOMBET M. 1, HJORTH L. 4, PRITCHARD-JONES K. 5, STILLER C. 6, STELIAROVA-FOUCHER E. 1
1 Cancer Surveillance Branch, International Agency for Research on Cancer, Lyon, France; 2 Faculty of Medicine, Selcuk University, Konya, Turkey; 3 Faculty of Medicine, Comenius University & National Institute of Children’s Diseases, Bratislava , Slovakia; 4 Lund University, Skane University Hospital, Department of Clinical Sciences Lund, Paediatrics, Lund, Sweden; 5 University College London, London, United Kingdom; 6 National Cancer Registration & Analysis Service, NHS England, United Kingdom
Background:
Population-based cancer registries collect information on all cancers occurring in a defined population and many are able to follow-up the registered patients for vital status or new cancer diagnosis. Therefore, their data could be used to assess risk of subsequent primary neoplasms (SPN) in the registered cases. As childhood cancers are rare, pooling data across large populations helps to quantify risk of subsequent cancer in these patients.
Objectives:
Within the study Cancer Risk in Childhood Cancer Survivors (CRICCS), funded by Children with Cancer UK, we estimated the overall risk of SPNs after childhood cancer using data from population-based cancer registries with wide socioeconomic diversity, as a basis for developing effective cancer control strategies.
Methods:
All patients diagnosed with a first malignant neoplasm (FPN) before the age of 20 years from 11 countries covered by 3 national and 21 regional cancer registries were included. The risk of subsequent primary neoplasms was evaluated using standardised incidence ratios (SIRs) and absolute excess risks (AERs) per 100,000 person-years overall and by sex, age group, first primary neoplasm, decade of FPN diagnosis, and country, and compared with the general population. Type of the second neoplasm succeeding the first one was examined.
Results:
Over a median observation period of 30 years and a median follow-up of 33 years by 2021, 60,524 FPNs and 1687 SPNs were ascertained. Overall, childhood cancer patients experienced a threefold increased risk of developing a subsequent cancer compared with the general population (SIR = 3.2; 95% CI: 3.1–3.3), with an AER of 17.1 per 100,000 person-years (95% CI: 16.3–17.9). SIR was highest for patients with hepatic FPN and lowest for those with carcinoma FPN. AER was highest for bone tumours and lowest for renal tumours. Risk varied by period of FPN diagnosis and by the attained age at SPN. Among the 1579 second primary neoplasms identified after a first primary neoplasm, the 50% were carcinomas (N=758) of thyroid gland (N=175), skin (N=153), breast (N=142) and lung (N=128). Second skin carcinoma most commonly occurred after a first skin carcinoma (N=68). Other common sequence were breast cancer (N=67), thyroid cancer (N=56) or skin carcinoma (N=41) that followed a Hodgkin lymphoma.
Conclusions:
The persistently elevated risk of subsequent primary neoplasms among childhood cancer survivors across diagnostic groups and socioeconomic settings underscores the need for lifelong follow-up and international collaboration. Sequence of tumours may provide indication for follow-up of the survivors. These findings, based on routinely collected population-based registry data, highlight the critical role of childhood cancer registries in evaluating long-term risks and informing evidence-based surveillance strategies. Strengthening registry infrastructure-particularly in low- and middle-income countries-and promoting international data sharing are essential to improve data completeness and support comparative survivorship research.