Comment on: Incidence and Outcome of Infants With Cancer in Canada: A Report From Cancer in Young People in Canada Database

To the Editor: We read with great interest the report by Sassine et al. describing the incidence and outcomes of infants with cancer in Canada, with comparative analyses between neonates (0 to <30 days) and older infants (30 days to <1 year) [1]. The authors demonstrated clinically meaningful differences in cancer distributions and survival across these age strata. To further quantify the underlying biological pattern, we examined the published cancer-type distributions through the lens of Shannon entropy, a well-established measure of distributional diversity [2]. The increase in diversity was driven primarily by greater representation of retinoblastoma, acute lymphoblastic leukemia, and nephroblastoma in older infants (Figure 1B). Conversely, the predominance of malignant extracranial germ-cell cancers in neonates, together with relative declines in myelodysplastic/myeloproliferative disorders, acted to dampen—but not eliminate—the overall increase in entropy. These findings are consistent with a shift from a concentrated, largely embryonal cancer spectrum at birth toward a more heterogeneous distribution that increasingly includes hematologic, renal, and neuro-oncologic malignancies later in infancy. Although the entropy used here is informational [2] rather than thermodynamic [3], the conceptual analogy is noteworthy: increasing entropy in this context reflects diversification of oncogenic processes across early developmental windows. Importantly, this approach does not replace conventional epidemiological metrics [4], but instead offers a compact, quantitative framework for summarizing complex distributions and identifying specific categories responsible for observed shifts. Our analysis complements the work of Sassine et al. by demonstrating that differences in cancer distribution across early infancy are not merely qualitative, but are quantitatively coherent when viewed through the lens of Shannon entropy. Future applications might include longitudinal comparisons beyond the first year of life, cross-country analyses, and integration with molecular features to assess whether increasing phenotypic diversity parallels increasing genetic heterogeneity. We thank the authors for generating a valuable dataset and for stimulating new perspectives on infant cancer biology. The author declares no conflicts of interest. Supporting Information Table S1 Numerical data and processing steps. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.