<prompt> In carcinoma head of pancreas nausea and vomiting is due toExternal compression of duodenumPoal vein infiltrationProliferation and infiltration into duodenumChemotherapy related  <response>: PRESENTING SYMPTOM FREQUENCY Jaundice Weight loss Abdominal pain Nauseavomiting Pruritus Fever Gastrointestinal bleeding Ref: Sabiston 20th edition Pgno: 1544 