Does prilosec successfully prevent cancer caused by gerd?

Possibly: Prilosec (omeprazole) and other ppis have a better track record in preventing complications and sequela of severe gerd (stricture/stenosis/ca) than less potent rx, like ranitidine (zantac) and other h2 blockers, sucralfate, antacids, "alternative" rx like mastic gum and deglyzirrhinated licorice the latter are ok if there is no severe inflammation/erosions, barrett's changes, .

No: This medication is used to treat symptoms, but it does not prevent cancer development. If the symptoms are removed, but you don't treat the underlying cause if the problem, you may not prevent the disease from progressing. In general, however, Prilosec is an excellent medication for reflux symptoms.