If you had lung cancer that has spread to other parts of your body would it probably be big enough to be seen on x-ray or your blood work be off?

Yes and no: When Cancer starts to spread, it begins as clusters of cells that form tiny colonies in other body parts. These will grow in size over a few months to become visible on X-rays and various diagnostic imaging tests such as CT scan and or PET scan. Blood tests do not show cancer cells , so we rely on the above imaging tests and repeat them periodically(every 2-3 months) to monitor for the tumor growt