It is well known that tobacco smoke adversely affects the prognosis of adult cancers, including myeloid leukemia. But less is known about the effects in children. Now, researchers at UC San Francisco and UC Berkeley are investigating the impact of pre- and post-natal exposures to tobacco smoke on the survival rate of children with acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML).
Leukemia is the most common childhood cancer comprised mainly of ALL followed by AML. Despite improvements in cancer survival, leukemia incidence has increased in recent decades in the United States, especially in the Latinx population and significant disparities persist by socioeconomic status (SES), race and ethnicity. Exposures to tobacco smoke from fathers before conception and from secondhand smoke after birth have been associated with increased risks of developing childhood ALL and AML. Yet minimal attention has been given to the possible impact of tobacco smoke on survival following leukemia diagnosis.
In a study published recently in Cancer Epidemiology, Biomarkers & Prevention, the UCSF research team showed that paternal preconception smoking decreased 5-year survival in children with AML.
The researchers evaluated whether pre- and post-natal exposures to tobacco smoke decreased 5-year survival of 1,235 childhood ALL and 188 childhood AML cases derived from a population-based case-control study in California. The patients were diagnosed between 1995 and 2015 (with a median follow-up time of 13.2 years). They analyzed data for tobacco smoking before conception, during pregnancy and after birth. The researchers also looked at parental education and income, clinical features and vital status through 2020, and also adjusted for sociodemographic characteristics and risk group (for ALL only).
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. It was observed that paternal preconception smoking may also reduce 5-year survival among ALL cases with particular molecular subtypes.
“As oncologists, knowing your patients’ history of tobacco smoke exposure is important so that it can be integrated into prognostic discussions regarding childhood leukemias,” said Lena Winestone, MD, senior author and UCSF assistant professor, specializing in pediatric malignancies. “At a minimum, primary care doctors can counsel families about the risks related to smoking in the pre-natal period for the health of future children.”