The impact of S-1 for the patient with lymph nodal metastasis biliary tract cancer as adjuvant chemotherapy: a multicenter database analysis

Although adjuvant chemotherapy is expected to improve the prognosis for patients with biliary tract cancer after curative resection, there is limited evidence regarding the efficacy and prognostic factors of adjuvant chemotherapy. We investigated the effective subgroups for whom adjuvant chemotherapy with S-1 in biliary tract cancer patients. 413 patients who underwent curative resection for biliary tract cancer at our four affiliated hospitals between 2009 and 2019 were included in this study. The association of adjuvant chemotherapy with long-term outcomes in overall and patient subgroups were investigated by univariate and multivariate analyses. Among overall patients, adjuvant chemotherapy with S-1 did not improve disease free survival (p = 0.29) and overall survival (p = 0.83). In the subgroup analysis, adjuvant chemotherapy with S-1 improved both disease-free and overall survival in patients with lymph node metastasis, advanced Stage (III and IV), and microscopic residual tumor. In 135 patients with lymph node metastasis, adjuvant chemotherapy with S-1 was given in 67 patients (50%). In the patients with lymph node metastasis, preoperative bile duct drainage (p = 0.01) and adjuvant chemotherapy (p = 0.04) were independent and significant predictors of disease-free survival, while preoperative bile duct drainage (p = 0.03), tumor differentiation (p = 0.03), and adjuvant chemotherapy (p = 0.03) were independent and significant predictors of overall survival. After resection of biliary tract cancer, adjuvant chemotherapy with S-1 appears to benefit those who had lymph node metastasis.