Brief summary

The researchers are doing this study to see if people with unexplained weight loss who have lung cancer screening are more likely to have or develop lung cancer than people without unexplained weight loss. The lung cancer screening will involve use of low-dose computed tomography (LDCT), a CT scan that gives off very low doses of radiation and can make detailed pictures of the lungs to help find tumors. The study researchers will also analyze participants' blood samples to determine if blood testing can be used to help to diagnose lung cancer.