If chest xray comes back abnormal and a ct scan is needed - does that mean cancer? if not cancer what are other possible answers

No : No it does not mean automatically cancer, cxr are notorious for showing non-specific abnormalities especially in smokers or former smokers. In these cases you do a ct scan to further evaluate the finding which could be anything, from non-cancerous nodules to scar tissue or even cancer.

Chest x-rays show: Big things, ct's define them better. Some turn out to be normal variations, or some benign masses that may have been there forever. The main issue is not to speculate but to define the problem, and plan a course of action the solves the worry of cancer, or proves that it is. The uncertainty is alarming; knowing, then plotting what to do will reassure you.

No: If you've been a smoker you could have damage to the lung tissue from that and a chest x r ay would be abnormal. Depending on where you grew up you could alsao have been exposed to fungal infections which would make the xray abnormal. However, cancer should be ruled out. Get the ct scan!

Not usually: Most of the abnormalities seen on a chest xray are not cancer. Old (or new) infections, scarring or fibrosis, benign sclerosis in a rib and benign tumors of the lung or lung lining are all possible, as well as lung cancer. A chest xray can sometimes predict if lung cancer is more likely, but a ct will provide a more definite assessment of the likelihood of cancer. A biopsy is sometimes needed.

Cannot tell: An abnormal chest xray is often followed by more testing, such as a ct, to try to tell why it is abnormal.

Not usually: Most of the abnormalities seen on a chest xray are not cancer. Old (or new) infections, scarring or fibrosis, benign sclerosis in a rib and benign tumors of the lung or lung lining are all possible, as well as lung cancer. A chest xray can sometimes predict if lung cancer is more likely, but a ct will provide a more definite assessment of the likelihood of cancer. A biopsy is sometimes needed.