Efficacy and safety of adjuvant chemotherapy in T1N0M0 intrahepatic cholangiocarcinoma after radical resection

Objective: Adjuvant chemotherapy is necessary for radical resection of intrahepatic cholangiocarcinoma (ICC) with a high risk of recurrence (T2-4, N1). However, its use in the treatment of early-stage ICC remains controversial. This study aimed to investigate the role of adjuvant chemotherapy after radical resection in patients with early-stage ICC (T1N0M0). Data and methods: The data of 148 patients with pathologically diagnosed ICC (T1N0M0) who underwent radical resection from January 2012 to January 2018 at the Sun Yat-sen University Cancer Center were retrospectively analyzed. Using consistent baseline data, Kaplan-Meier survival curves were constructed to compare relapse-free survival (RFS) and overall survival (OS) between patients who received postoperative adjuvant chemotherapy (AC group) and those who received only surgical treatment (non-AC group). Univariate and multivariate Cox regression analyses were used to screen for independent prognostic factors affecting survival. The RFS and OS of patients were analyzed after the administration of three adjuvant chemotherapy regimens (gemcitabine + capecitabine [GX], gemcitabine + cisplatin [GP], and capecitabine monotherapy [X]). Finally, the safety of adjuvant chemotherapy was evaluated based on the incidence of grade 1-4 adverse events. Results: The median RFS was 18 months in the non-AC group and 25 months in the AC group. The median OS was 34 months in the non-AC group; however, it was not reached in the AC group. The OS of the AC group was significantly higher than that of the non-AC group (P = 0.005). Multivariate Cox analysis demonstrated that nerve invasion (P = 0.001), preoperative elevation of cancer antigen 19-9 (CA 19-9) levels (P = 0.009), and postoperative adjuvant chemotherapy (P = 0.009) were independent prognostic factors for early-stage ICC after radical resection. The OS rates of the GX, GP, X, and non-AC groups were significantly different (P = 0.023) and were higher in the GX group than in the non-AC group (P = 0.0052). Among patients with elevated preoperative CA 19-9 levels, the OS rate was higher in the AC group than in the non-AC group (P = 0.022). In terms of safety, the incidence of grade 3 or 4 adverse reactions was < 18.2% in the GX, GP, and X groups, without the occurrence of death owing to such reactions. Conclusion: Adjuvant chemotherapy can prolong OS among patients with early-stage ICC who have undergone radical resection. Preoperative elevation of CA 19-9 levels and nerve invasion are independent prognostic factors for poor survival outcomes for early-stage ICC after radical resection. All chemotherapy regimens used in the study are safe.