Abstract
BACKGROUND: JCOG1113 is a randomized phase III trial that showed non-inferiority of gemcitabine plus S-1 to gemcitabine plus cisplatin in patients with advanced biliary tract cancer. Assessment of inter-institutional heterogeneity in chemotherapy contributes to confirm generalizability and reliability of the study itself. However, there have been no studies conducted to assess the heterogeneity among participating centers in randomized phase III trials for biliary tract cancer. METHODS: The objective of this post-hoc analysis was to assess the inter-institutional heterogeneity in the overall survival and progression-free survival of patients with advanced biliary tract cancer treated with first-line chemotherapy in the JCOG1113 trial. The heterogeneity in the overall survival and progression-free survival was assessed according to three factors: hospital volume, experience in medical oncology and experience in biliary intervention. A total of 300 advanced biliary tract cancer patients were analyzed. There were no statistically significant trends observed between hospital volume, experience in medical oncology, or experience in biliary intervention and overall survival (hospital volume: adjusted trend P value = 0.6796; experience in medical oncology: adjusted trend P value = 0.4092; experience in biliary intervention: adjusted trend P value = 0.6112). Similarly, no statistically significant trends were observed between these factors and progression-free survival (hospital volume: adjusted trend P value = 0.3000; experience in medical oncology: adjusted trend P value = 0.1108; experience in biliary intervention: adjusted trend P value = 0.2898). CONCLUSIONS: This study revealed no inter-institutional heterogeneity in the overall survival and progression-free survival in the JCOG1113 study population of advanced biliary tract cancer patients.