Different Oncologic Outcomes According to Margin Status (High-Grade Dysplasia vs. Carcinoma) in Patients Who Underwent Hilar Resection for Mid-Bile Duct Cancer

SIMPLE SUMMARY: For hilar cholangiocarcinoma (HCCA), margin positivity after hilar resection for bile duct cancer is commonly observed due to its longitudinal spread along the subepithelial plane; however, we cannot draw conclusions regarding the prognostic effects of margins with high-grade dysplasia (HGD) or carcinoma. This study aimed to investigate the significance of positive bile duct margins and indications for extended resection in patients with middle bile duct cancer and to analyze the incidence of the R1 HGD margin and its clinical significance. We found that overall survival and disease-free survival in the R1 HGD–CIS margin were comparable with the R0 margin and significantly better than the R1 carcinoma. Extended resection should be considered in patients with R1 carcinoma-positive margins; however, extended resection in cases of R1 HGD-positive margins may not be necessary. ABSTRACT: Margin positivity after hilar resection (HR) for bile duct cancer is commonly observed due to its longitudinal spread along the subepithelial plane; nevertheless, we cannot draw conclusions regarding the prognostic effects of margins with high-grade dysplasia (HGD) or carcinoma. We aimed to investigate the oncologic effect according to the margin status after HR, particularly between the R1 HGD and the R1 carcinoma. From 2008 to 2017, 149 patients diagnosed with mid-bile duct cancer in Samsung Medical Center, South Korea, were divided according to margin status after HR and retrospectively analyzed. Recurrence patterns were also analyzed between the groups. There were 126 patients with R0 margins, nine with R1 HGD, and 14 with R1 carcinoma. The mean age of the patients was 68.3 (±8.1); most patients were male. The mean age was higher in R1 carcinoma patients than in R1 HGD and R0 patients (p = 0.014). The R1 HGD and R1 carcinoma groups had more patients with a higher T-stage than R0 (p = 0.079). In univariate analysis, the prognostic factors affecting overall survival were age, T- and N-stage, CA19-9, and margin status. The survival rate of R0 was comparable to that of R1 HGD, but the survival rate of R0 was significantly better compared to R1 carcinoma (R0 vs. R1 HGD, p = 0.215, R0 vs. R1 carcinoma, p = 0.042, respectively). The recurrence pattern between the margin groups did not differ significantly (p = 0.604). Extended surgery should be considered for R1 carcinoma; however, in R1 HGD, extended operation may not be necessary, as it may achieve oncologic outcomes similar to R0 margins with HR.