How long should follow-up be continued after R0 resection of perihilar cholangiocarcinoma?

Although several studies have been conducted on the patterns of recurrence in resected perihilar cholangiocarcinoma, the appropriate follow-up period after resection is still controversial. Consecutive patients who underwent an R0 resection of perihilar cholangiocarcinoma between 2001 and 2014 were reviewed retrospectively, focusing on the time and site of initial recurrence. A Cox proportional hazards model was used for multivariate analysis. During the study period, 404 patients underwent R0 resection, of whom 242 patients (59.9%) developed a recurrence. The most common site of recurrence was locoregional, followed by peritoneum and liver. Approximately 70% of patients were asymptomatic when recurrence was detected. The median survival time in all cohorts was 4.8 years, and the estimated cumulative probability of recurrence was 54.3% at 5 years and 65.7% at 10 years. Multivariate analyses revealed that lymph node metastasis (hazard ratio 2.80, P < .001) and microscopic venous invasion (hazard ratio, 1.70, P < .001) were independent risk factors for recurrence-free survival. The cumulative probability of recurrence in 84 patients with 2 risk factors was nearly 90% at 5 years; even in the 178 patients without risk factors, the probability at 5 years was 30%, and thereafter, the probability of recurrence gradually increased, reaching nearly 50% at 10 years. No trends in the time and site of recurrence were detected. Approximately 60% of patients with perihilar cholangiocarcinoma experience recurrence after R0 resection. Even in patients without an independent risk for recurrence, the recurrence probability is high, reaching nearly 50% at 10 years. Thus, close surveillance for 10 years is necessary even after R0 resection of perihilar cholangiocarcinoma.