External beam radiation therapy as an agent in the aetiology of carcinoma of the bile duct: a report on two patients.

Two cases of biliary duct carcinoma occurring in patients who had received prophylactic abdominal irradiation 17 years previously are described. Although external beam radiation has been implicated in the aetiology of many malignancies, there is only one previous report of it being associated with carcinoma of the bile duct. All patients receiving external beam irradiation for curable malignancies require long term follow-up so that treatment induced malignancies may be detected.