Can acid reflux cause esophageal cancer without the patient ever having barretts esophagus?

Possible: Majority of the cases metaplasia resulting in columnar epithelium is called the barrets oesophsgus resulting the cancer in it. Some times sqamous cell cancers of lower third esophagus cases has no barrets ulcer but has reflex oesophagitis but not attributed as cause of cancer.

Possible but unusual: Most likely lower esophageal adenocarcinoma is caused by gerd, which changes the lining of the lower esophagus into that of the stomach (barrett's) which is a precursor for adenocarcinoma. However, one could have squamous cell type without gerd. Best to review with your gastroenterologist.