help me...so difficult...about probability?

sensitivity - the sentsitivity of a symptom is the probability that the symptom is present given that the person has a disease.specificity - the specificity of a symptom is the probability that the symptom is not present given that the person does not have a disease.suppose the disease is lung cancer and the symptom is cigarette smoking. if we assume 87% of people with lung cancer and 20.9% of people without lung cancer are smokers. what are the sensitivity and spesificity in this case? can cigarette smoking be used as a diagnostic tool for predicting lung cancer? why?