Can you tell me the major signs and differences between lung cancer vs other benign illnesses like asthma, bronchitis, or an infection?

Asthma, COPD. And bronchitis have predictable signs and symptoms, lung cancer may have none or all of these, and already spread. We no know that if you smoke, and are over 50, a screening ct with low dose spiral ct detcts cancer and lowers all cause mortality. Best prevention is to never smoke, or stop if you do, at any age.