To assess the influence of tumour volume on clinicopathological findings and survival time after radical operation for periampullary carcinoma. Retrospective study. Kaiser-Franz-Josef-Hospital, Vienna, Austria. 72 of 75 consecutive patients who underwent pancreaticoduodenectomy for periampullary carcinoma between 1 January 1979 and 31 December 1991. Cancers were divided into four groups according to volume (mm3) and the incidence of lymph node involvement, infiltration of surrounding tissues and of visceral vessels, and histologically non-radical resections were calculated, as was the length of survival after resection. There were 22 tumours with a volume of 0-2500 mm3 (group 1), 12 with a volume of 2,501-5,000 mm3 (group 2), and 19 each in groups 3 (5,0001-10,000 mm3) and 4 (more than 10,000 mm3). All carcinomas of the common bile duct (n = 5) and the papilla of Vater (n = 18) were in groups 1 and 2, whereas 38 of the 49 carcinomas of the head of pancreas were in groups 3 and 4. Lymph nodes were involved in 3 (14%), 6 (50%), 13 (68%) and 14 (74%); the surrounding tissues were infiltrated in 6 (27%), 8 (67%), 11 (58%) and 12 (63%); the main visceral vessels were involved in 0, 3 (25%), 5 (26%) and 8 (42%); and the resections were histologically not radical in 0, 2 (17%), 7 (37%) and 9 (47%), respectively. There was significant negative correlation (p < 0.0001) between tumour mass and survival. These results explain at least in part the poorer prognosis after radical resection of carcinoma of the head of the pancreas.