 [ Symptoms ] i have a compromised immune system due to depression can repeated treatment for bronchitispneumonia cause lung cancer  i am being treated with singular symbicort proair and tessalon if i cough up green phlegm i will occasionally return for antibiotic treatment i have received 3 chest x rays two evidenced bacteria the third was negative am i at risk for lung cancer the consistent cough troubles me [ Disease ] you can not really rule out lung cancer but it likely would not be caused by your therapy or the x rays you can help your compromised immune system plus the depression by getting plenty of antioxidant rich foods and exercising at least a few times a week it may not be a cure but it will be a complement to your other treatments