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.