How accurate is a chest x-ray for diagnosing lung cancer?

Poor sensitivity: Unfortunately chest xray has poor sensitivity for the diagnosis of lung cancer. Small cancers can "hide" behind structures on the xray and this affects the ability of the xray to be sensitive enough to pick up these findings early. A ct scan of the chest is likely a better way to detect cancer but it has disadvantages including the expense and radiation exposure.

Not very: A chest ct is much more accurate as it provides much better detail.