Introduction:
Survival rates of childhood cancer have increased in recent decades to reach 80% in high-income countries. At the same time, the appearance of late effects derived from the treatments has been increasing, estimating that up to 70% of childhood cancer survivors (CCS) will experience some late effect throughout their life. Exposure to environmental tobacco smoke (ETS) will increase the likelihood of these late effects. Therefore, it is an important mission in long-term follow-up programs to address smoking status in all household members.
Aim: To present the prevalence of exposure to ETS in a group of CCS who attend a long-term follow-up program and observe the differences at one year after a brief tobacco intervention.

Material and Methods:
Descriptive cross-sectional study. Smoking status was analyzed in the cohabitants of 135 CCS (7 - 34 years) who attend the Long-Term Follow-Up Program in the Clinical University Hospital Virgen de la Arrixaca (Murcia, Spain) between January 2016 and December 2017 after a brief tobacco intervention.

Results:
In the first visit, 52.6% of CCS lived with a smoker in the home. 37.7% of mothers and 33.6% of fathers were smokers. In 8.9% of households there were other smokers. One year after the first visit, exposure to ETS in the houses decreased to 43.7% (30% mothers, 27.8% parents, 8.9% others).

Conclusions:
The parents of CCS smoke more than the national average, exposing their children to the harmful effects of tobacco. However, it is observed that it is a population group with a strong motivation to abandon consumption. More intensive interventions are needed to increase the dropout rate.

Funding Statement:
The authors received no specific funding for this work.