Prognostic implications of tumor diameter in carcinoma of the head of the pancreas. Two hundred twenty patients with a carcinoma in the head of the pancreas were divided into three tumor diameter groups: group 1, 0.5 to 4.4 cm (n = 72); group 2, 4.5 to 6.0 cm (n = 77); and group 3, 6.1 to 15.0 cm (n = 71). For these tumor diameter groups a six-fold eliminatory curability analysis was performed. Of the patients with liver metastases in group 1 the last patient had died at 10 months and in groups 2 and 3 no patients were alive at 18 months after the start of complaints. Patients with extrahepatic metastases did not survive 12 months in group 1, 16 months in group 2, and 25 months in group 3. The 6% actuarial survival rate for inoperable patients was reached in group 1 after 17 months, in group 2 after 36 months, and in group 3 after 27 months after the start of complaints. For groups 1 through 3 in curable, but not curatively operated patients, the respective 0% actuarial survival rate was reached at 24 months, 23 months, and 14 months. The 0% actuarial survival rate in patients with irresectable vessel invasion was reached in group 1 at 33 months, in group 2 at 23 months, and in group 3 at 25 months. The 0% actuarial survival rate in patients with an irresectable tumor was reached at 33 months, 31 months, and 27 months after the start of complaints in groups 1, 2, and 3, respectively. The 0% actuarial survival rate in curatively operated patients was reached in group 3 after 26 months and in group 2 after 29 months. In group 1 25% of the patients were alive at 36 months after the start of complaints. Small tumors were associated with the greatest chance of curative operation and on average had the longest survival. However, small tumors with liver or other metastases carried a worse prognosis than large tumors with liver or other metastases. If tumors were found not to be resectable at the time of operation, the size of the tumor did not appear to affect survival. 