Introduction: The importance of gallbladder carcinoma spread to the cystic duct has not yet been described. Although the cystic duct is contiguous with the gallbladder, it is located in the hepatoduodenal ligament and differs in structure from the gallbladder. The incidence and prognostic significance of cancer spread to the cystic duct in patients with gallbladder cancer is unclear.
Methods: Surgical specimens from 42 patients who underwent resection for advanced gallbladder carcinoma were examined retrospectively.
Results: Altogether, 13 (31%) of the patients had cancer spread to the cystic duct. The incidences of perineural invasion, lymph node metastasis, and venous invasion were significantly higher in these patients than in the other 29 patients without cancer spread to the cystic duct (P = 0.027, 0.034, and 0.034, respectively). The 3- and 5-year survival rates of these 13 patients were significantly lower than those of the other 29 patients (15.4% vs. 51.0% and 7.7% vs. 46.6%, respectively, P < 0.0001 each). Multivariate analysis using the Cox proportional hazard model identified positive cancer spread to the cystic duct and depth of invasion (beyond serosa) as significant independent indicators of a poor prognosis.
Conclusions: Cancer spread to the cystic duct is an indicator of poor prognosis in patients with gallbladder carcinoma. This may be due to the high incidence of concomitant perineural invasion and lymph node metastasis associated with cancer spread.