Holst A, Ekman J, Petersson-Ahrholt M, Relander T, Wiebe T, Linge HM. Identifying causal relationships of cancer treatment and long-term health effects among 5-year survivors of childhood cancer in Southern Sweden.
COMMUNICATIONS MEDICINE 2022;
2:21. [PMID:
35603279 PMCID:
PMC9053221 DOI:
10.1038/s43856-022-00081-z]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 01/31/2022] [Indexed: 12/01/2022] Open
Abstract
Background
Survivors of childhood cancer can develop adverse health events later in life. Infrequent occurrences and scarcity of structured information result in analytical and statistical challenges. Alternative statistical approaches are required to investigate the basis of late effects in smaller data sets.
Methods
Here we describe sex-specific health care use, mortality and causal associations between primary diagnosis, treatment and outcomes in a small cohort (n = 2315) of 5-year survivors of childhood cancer (n = 2129) in southern Sweden and a control group (n = 11,882; age-, sex- and region-matched from the general population). We developed a constraint-based method for causal inference based on Bayesian estimation of distributions, and used it to investigate health care use and causal associations between diagnoses, treatments and outcomes. Mortality was analyzed by the Kaplan–Meier method.
Results
Our results confirm a significantly higher health care usage and premature mortality among childhood cancer survivors as compared to controls. The developed method for causal inference identifies 98 significant associations (p < 0.0001) where most are well known (n = 73; 74.5%). Hitherto undescribed associations are identified (n = 5; 5.1%). These were between use of alkylating agents and eye conditions, topoisomerase inhibitors and viral infections; pituitary surgery and intestinal infections; and cervical cancer and endometritis. We discuss study-related biases (n = 20; 20.4%) and limitations.
Conclusions
The findings contribute to a broader understanding of the consequences of cancer treatment. The study shows relevance for small data sets and causal inference, and presents the method as a complement to traditional statistical approaches.
Survivors of childhood cancer can develop late effects in adulthood. Knowledge about possible late effects can improve childhood cancer treatments and assist in follow-up. We developed a method to identify causative links between treatments and health outcomes. We applied it to a Swedish patient cohort and identified 98 causative links between treatments and outcomes, many of which are already known. Some, however, have not been previously described, including links between certain treatments and eye conditions or viral infections. We also confirm that childhood cancer survivors use more health care and have higher mortality compared to the general population. This study helps to create a better understanding of the late effects of cancer treatment in children and may help to guide strategies to monitor and treat children to avoid these effects.
Holst et al. study the relationship between cancer treatments and long-term health effects using registry data on childhood cancer survivors in Sweden. The authors utilize a causal inference approach to establish relationships between certain therapies and viral infections, eye conditions, and reproductive conditions, amongst others.
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