Role of adjuvant therapy after R0 resection for patients with distal cholangiocarcinoma

Background The optimal treatment strategy for cholangiocarcinoma (CC) after curative resection remains controversial. The aim of this study was to analyze the role of adjuvant therapy in R0-resected distal CC. Methods We retrospectively reviewed the medical records of patients who underwent R0 resection for distal CC at six cancer centers in Korea. Adjuvant therapy consisted of chemotherapy (CT), chemoradiotherapy (CRT), or radiotherapy (RT). The outcomes of the study were overall survival (OS) and recurrence-free survival (RFS). Results A total of 158 patients were included in the analysis; 47 patients (29.7 %) had lymph node involvement. Fifty-six patients (35.4 %) received adjuvant therapy (CT/CRT/RT: 27/20/9, respectively). Patients with advanced TNM stage (P < 0.001), T3/T4 disease (P = 0.009), positive lymph nodes (LN; P = 0.052), and elevated baseline carbohydrate antigen 19-9 (P = 0.071) were more likely to receive adjuvant therapy. The effect of adjuvant therapy varied according to treatment modality. A multivariable analysis showed a significant improvement in OS after CT [hazard ratio (HR) 0.21, 95 % confidence interval (CI) 0.08-0.53, P = 0.001] and CRT (HR 0.25, 95 % CI 0.08-0.83, P = 0.024). However, RT alone was associated with shorter OS (HR 2.38, P = 0.040), along with T3/T4 disease (HR 2.12, P = 0.012) and positive LN (HR 2.30, P = 0.008). RFS benefited from adjuvant treatment with CT (HR 0.34, P = 0.002) and CRT (HR 0.33, P = 0.004), but not with RT alone (HR 1.42, P = 0.361). In the subset analysis according to LN status, adjuvant therapy not including RT alone was associated with a significant OS and RFS advantage in both LN-negative and LN-positive patients. Conclusions Our results show that patients receiving CT or CRT had significant improvements in OS and RFS. In addition, a benefit of adjuvant therapy (except RT alone) was observed even in LN-negative patients.