Pulmonary function tests (PFTs) are a part of the routine follow-up of patients receiving anti-cancer treatment. Treatment is frequently associated with diverse pulmonary damage which may become functionally and clinically evident many years later. PFTs may help to quantify the damage in the lungs; help to evaluate the point at which lung function deviates from normal to allow early intervention before irreversible lung damage occurs and thereby to reduce morbidity and mortality.

Reliable PFTs in the preschool age have traditionally been difficult to perform, but recent publications have demonstrated that the majority of preschool children can produce reproducible forced expiratory flow volume (FEVC) curves with proper coaching techniques. This recent development may enable studying the long term effect (years) of treatment on lung function in young children suffering from hemato-oncologic diseases.

All pediatric patients (age 3-7 years) with hemato-onclogic diseases that were treated at the Hemato-Oncology Department, and were sent to the pediatric pulmonary unit at the Safra children's hospital, Sheba medical center, Ramat-Gan, Israel, to perform lung function tests, as a part of a 3-year follow-up study.

Inclusion Criteria:

• All pediatric patients (age 3-7 years) with hemato-onclogic diseases that were treated at the Hemato-Oncology Department, and were sent to the pediatric pulmonary unit.