Clinical evaluation of late outcomes in Dutch childhood cancer survivors: Methodology of the DCCSS LATER 2 study

Background

Childhood cancer survivors face late health problems; despite advances in research, details on risk remain unclear. We describe the methodological aspects of the Dutch Childhood Cancer Survivor Study (DCCSS) cross-sectional clinical study (LATER 2 study).

Procedure

From the multi-center DCCSS LATER cohort of 6165 five-year survivors diagnosed during 1963–2001, we invited 4735 eligible survivors in 2016, as well as siblings and parents of survivors. Gaps in evidence identified during development of surveillance guidelines were translated into clinical research questions for 16 outcome-specific subprojects. The regular care visit to the LATER outpatient clinic forms the backbone of outcome assessment complemented with research-defined measurements (physical examination, clinical tests, questionnaires). Furthermore, blood/saliva samples were taken for deoxyribonucleic acid (DNA) extraction.

Results

In total, 2519 (53.2%) survivors participated in the LATER 2 study. When comparing participants with nonparticipants, we observed that males, CNS survivors, and those treated with surgery only were less likely to participate. Of the participating survivors, 49.3% were female. Median time since childhood cancer diagnosis was 26.9 years (range 14.8–54.7 years) and median attained age was 34.4 years (range 15.4–66.6 years).

Conclusions

The high-quality data generated in the LATER 2 study will provide valuable insights into risks of and risk factors for clinical and physical and psychosocial health outcomes and factors for early recognition of those health outcomes in long-term childhood cancer survivors. This will contribute to fill in important gaps in knowledge and improve the quality of life and care for childhood cancer survivors.     

A comprehensive review of 30 years of pediatric clinical trial radiotherapy dose constraints

Background

Radiation therapy normal tissue dose constraints are critical when treating pediatric patients. However, there is limited evidence supporting proposed constraints, which has led to variations in constraints over the years. In this study, we identify these variations in dose constraints within pediatric trials both in the United States and in Europe used in the past 30 years.

Procedure

All pediatric trials from the Children's Oncology Group website were queried from inception until January 2022 and a sampling of European studies was included. Dose constraints were identified and built into an organ-based interactive web application with filters to display data by organs at risk (OAR), protocol, start date, dose, volume, and fractionation scheme. Dose constraints were evaluated for consistency over time and compared between pediatric US and European trials

Results

One hundred five closed trials were included—93 US trials and 12 European trials. Thirty-eight separate OAR were found with high-dose constraint variability. Across all trials, nine organs had greater than 10 different constraints (median 16, range 11–26), including serial organs. When comparing US versus European dose tolerances, the United States constraints were higher for seven OAR, lower for one, and identical for five. No OAR had constraints change systematically over the last 30 years.

Conclusion

Review of pediatric dose-volume constraints in clinical trials showed substantial variability for all OAR. Continued efforts focused on standardization of OAR dose constraints and risk profiles are essential to increase consistency of protocol outcomes and ultimately to reduce radiation toxicities in the pediatric population.