Radiological Shape of the Tumor Predicts Progression and Survival in Resected Extrahepatic Cholangiocarcinoma.

Background: The histological features and radiological shape of extrahepatic cholangiocarcinoma (eCCA) have not been widely studied in relation to prognosis. Multi-detector computed tomography (MDCT) is thought to be useful in diagnosis of progress and tumor distribution; it can also show morphological differences (round, triangular, and square forms) at the tumoral obstruction sites. Histological types of eCCA may be revealed, with potential association with tumor growth and survival.

Methods: We examined the distribution of tumor radiological shape subtypes on MDCT. The surgical outcomes of consecutive patients with eCCA who underwent macroscopic curative resection were reviewed.

Results: CT subtypes in 109 patients were 62 triangular, 35 square, and 12 round. There were clear prognostic differences in long-term survival rates (P < 0.001); 5-year survival rates were 100% in round, 64% in triangular, and 19% in square types. There was no recurrence in any cases of round-type tumor at the site of obstruction. Depth of tumor invasion and rates of nodal involvement were significantly higher in triangular and square-type tumors than in round-type tumors. In papillary adenocarcinoma, radiological obstructions were round type in seven patients (78%) and triangular type in two patients (22%). In tubular adenocarcinoma, all round-type tumors were well differentiated, the ratio of square-type tumors increasing as the degree of differentiation decreased from "well" to "moderate," and "poor" respectively (23%, 39%, 57%; P = 0.033).

Conclusions: Tumor radiological shape predicts tumor progression, histological type, and survival in eCCA. This information may be helpful in preoperative radiological staging on MDCT.