CT (computerized tomography) scans can detect lung cancer very early, while the disease is still localized and treatable by a surgeon-although the efficacy of treatment is unclear. Henschke et al (2006) found 484 lung cancers in a large-scale screening program, and estimated the 5- year survival rate among these patients as 85%. Most of the cancers were resected, that is, surgically removed. By contrast, among patients whose lung cancer is diagnosed when the disease becomes symptomatic (e.g., with persistent cough, recurrent lung infections, chest pain), the 5-year survival rate is only about 15%. Do these data make a case for CT screening? Discuss briefly.