Children with cancer, parents, and clinicians, face difficult decisions when cure is no longer possible. Little is known about decision-making processes, how agreement is reached, or perspectives of different actors. Professionals voice concerns about managing parental expectations and beliefs, which can be contrary to their own and may change over time. We conducted the first systematic review to determine what constitutes best medico-legal practice for children under 19 years as context to exploring the perspectives of actors who make judgements and decisions when cancer treatment is no longer curative.

The world literature shows that empirical research regarding the process of decision-making when cancer in adolescents is no longer curable has been conducted in High-income, English speaking countries. The objective of the current study was to explore in-depth and to explain the decision-making process from the perspective of Mexican oncologists, parents, and affected adolescents and to identify the ethical principles that guide such decision-making. Purposive, qualitative design based on individual, fact-to-face, semi-structured, in-depth interviews. The participants were thirteen paediatric oncologists, 13 parents or primary carers, and six adolescents with incurable cancer. The participants were recruited from the paediatric oncology services of three national tertiary-care medical centres in Mexico City. The oncologists stated that they broach the subject of palliative management when they have determined that curative treatment has failed. Respect for autonomy was understood as the assent of the parent/adolescent to what the oncologist determined to be in the best interest of the adolescent. The oncologists thought that the adolescent should be involved in the decision-making. They also identified the ability to count on a palliative care clinic or service as an urgent need. For the parents, it was essential that the oncologist be truly interested in their adolescent child. The parents did not consider it necessary to inform the child about impending death. The adolescents stated that the honesty of their oncologists was important; however, several of them opted for a passive role in the decision-making process. The findings of this study evidence that to achieve good medical practice in low-middle income countries, like Mexico, it is urgent to begin effective implementation of palliative care, together with appropriate training and continuing education in the ethics of clinical practice.

Objective: To test whether hypervitaminosis B12 is useful for prognosis of all-cause mortality. Methods: Meta-analysis of longitudinal, observational, epidemiologic studies. PubMed, Scopus, Web of Science, Google Scholar, and ProQuest One Academic were searched from inception to 30 June 2024. Studies including humans aged ≥18 years with hypervitaminosis B12, and in whom the outcome variable was all-cause mortality, were included. Two reviewers screened, abstracted (using standardized data collection sheet), and appraised articles (ROBINS-E framework) independently. Frequentist and Bayesian approaches were used for the meta-analysis. Results: A total of 28 studies were included in the meta-analysis (among the 69,610 participants, 15,815 all-cause deaths were reported). High serum levels of B12 increased marginally the risk of all-cause mortality specifically among chronic diseases (RR = 1.40; 95% IC = 1.05 to 1.85) and hospitalized (RR = 1.57; 95% IC = 1.19 to 2.07). In the meta-regression, these results were not statistically significant. The Bayesian analysis confirmed the risks of the mentioned groups; however, it was limited by the number of studies that contained the necessary information. The methodology applied and the clinical heterogeneity of each included study bring up the idea that artefacts might be involved when mortality is found to be high for hypervitaminosis B12. Conclusions: This meta-analysis did not show that hypervitaminosis B12 represents a higher risk of all-cause mortality in adults.

This letter to the editor is inspired on the idea of the natural history of disease and levels of prevention as published by doctors Leavell and Clark in 1957 to present an analogous idea whose purpose is preventing, repairing opportunely and rehabilitating after a non-clinical adverse event the services provided by a health organization through its physicians and non-physician personnel.