I'm 50/50 on whether it's cancer. It's one of 3 things based on its density (it is absolutely a solid tissue mass), NSCLC (Non-Small Cell Lung Cancer), a space filling lesion (which is a tumor that doesn't stop growing, but has no potential to spread anywhere else. It's one step up from benign tumor [which are self-limiting in size] and one step down from actual cancer), or a benign tumor. The size would be a good indicator that it's cancer, that much more so if he's had a CXR in the last 5 years and it wasn't present. The more recent the CXR he has had for comparison and it wasn't present makes it that much more likely it is cancer since it means it grew that much faster to its current size which is a classic feature of cancer only. The shape is 50/50 on cancer vs. tumor. The finer features of it would likely tell the truth. It certainly has all the features I would expect for cancer on a CXR (Chest X-Ray). But, CXR's are so low-res, they can never give you a definitive answer. If I was him I'd skip the CT and go right to biopsy. A biopsy is really the only way to ever know for sure what the disposition of a solid mass is. CT's aren't nearly as accurate as a biopsy as far as sensitivity and specificity.