Microscopic liver metastasis: prognostic factor for patients with pT2 gallbladder carcinoma

Hepatic metastasis is the most frequent mode of recurrence of advanced gallbladder cancer after radical resection. The aims of this study were to clarify the clinical significance of microscopic liver metastasis from pT2 gallbladder cancer and to clarify whether partial hepatectomy can prevent hepatic recurrence in patients with microscopic liver metastasis. The subjects included 20 patients with pT2 tumors who underwent radical surgery and partial hepatectomy with lymph node dissection. Microscopic liver metastasis was defined as a distant metastatic nodule including cancer cell nests in the lumen of the portal vein and discrete nodular lesions in the liver, all less than 5 mm in diameter. Cox's proportional hazard regression was used to analyze factors that contributed to outcomes. Microscopic metastases were detected in the resected livers from 5 of 20 patients. There were more metastatic lesions within 1 cm of the gallbladder bed than were located 1 to 2 cm away from it. Microscopic liver metastases showed a strong correlation with the extent of blood vessel invasion around the primary tumor and were frequently detected in patients with a primary tumor localized on the hepatic side and with more than 3 cm of subserosal invasion. In four of five patients with microscopic liver metastases, recurrence was found in the remnant liver, which led to death within 15 months after the initial operation. Microscopic liver metastasis, operative curability, and lymph node metastasis were assessed as independent prognostic factors. A large proportion of patients with microscopic liver metastasis suffered from hepatic recurrence. Our results suggest that partial hepatectomy alone cannot prevent hepatic recurrence in patients with microscopic liver metastasis.