Pre- and post-natal exposures to tobacco smoking and survival of childhood acute lymphoblastic and myeloid leukemias in California, United States
Menée aux Etats-Unis à partir de données portant sur 1 235 patients pédiatriques atteints d'une leucémie lymphoblastique aiguë et sur 188 patients pédiatriques atteints d'une leucémie myéloïde aiguë entre 1995 et 2015 (durée médiane de suivi : 13,2 ans), cette étude analyse l'effet, sur la survie à 5 ans, d'une exposition pré- et post-natale au tabagisme parental
Background: Tobacco smoke adversely affects the prognosis of adult cancers including myeloid leukemia, but less is known in children. Methods: We evaluated whether pre- and post-natal exposures to tobacco smoke decrease 5-year survival of 1,235 childhood acute lymphoblastic leukemia (ALL) and 188 childhood acute myeloid leukemia (AML) cases derived from a population-based case-control study in California (United States). Cases were diagnosed between 1995 and 2015 (median follow-up time of 13.2 years overall). We obtained data on tobacco smoking (before conception, during pregnancy, after birth), parental education and income, clinical features, and vital status through 2020. Cox proportional hazards regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CI) for mortality associated with smoking, adjusting for sociodemographic characteristics and risk group (ALL only). Results: About 23% of mothers and 39% of fathers reported smoking and 130 children with ALL and 52 with AML died within 5 years. For AML, increased risks of death were observed among children whose fathers smoked before conception compared to non-smoking fathers (HR=1.41; 95% CI:0.95-3.44 and 3.47; 95% CI:1.37-8.81, respectively for <20 vs. >20 cigarettes per day; p-trend=0.01); HR for child’s passive smoking =1.74, 95% CI:0.81-3.73. Paternal preconception smoking may also reduce 5-year survival among ALL with favorable prognostic molecular subtypes (high-hyperdiploidy and absence of IKZF1 gene deletion), although the associations did not reach statistical significance (p-value for heterogeneity=0.07). Conclusion: Paternal preconception smoking decreased 5-year survival of childhood AML. Impact: Knowledge of exposure to tobacco smoking should be integrated in the treatment plan of childhood leukemias.