Does a sternum x-ray rule out lung cancer?

NO: The x-ray may be one of the first studies ordered. But, plain film radiograph (x-ray) does not rule out cancer. Ultimately, the majority of abnormalities found by radiographic studies (x-ray, ct, mri, nuclear, etc...) require tissue biopsy to potentially "rule-out cancer".

No: This x-ray is too limited. We have proven a ct of the chest is very helpful in screening for hi risk people though you don't fit age (55 to 74 who smoked > pack of cig/day for >30 ys and who are still smoking or who <15 yrs ago). Smoking volume history, infections and other factors should be considered before scans. With suspicion your primary md may still start with a chest xray before ct.