Mrcp showed biliary stricture. no mass etc. now having a ercp. afraid of biliary cancer. how common?

Not most common path: MRCP which is non invasive is mostly used to image stones in duct that might be associated with some jaundice or biliary pain. When no path found then ERCP with scope in pancreatic biliary ducts can visualized, sample bile for cell, and biopsy for tumor. If no mass seen on scans and tumor present on bx then RT, chemo followed by resection indicated though incidence of tumor vs. inflammation low

Low likelihood: Since the mrcp didn't show any mass there is a low likelihood of there being a biliary tract tumor. In my experience biliary strictures are not usually associated with cancer, but your gastroenterologist is much better qualified to answer your question.