This study retrospectively analyzed 16 patients with distal bile duct cancer who underwent chemoradiation therapy followed by surgery between March 2006 and December 2015 in our institute. The clinicopathological characteristics of these patients are shown in Table I. All patients needed preoperative biliary drainage due to obstructive jaundice. Four patients underwent percutaneous transhepatic cholangiodrainage and twelve underwent endoscopic retrograde biliary drainage. They were diagnosed with resectable distal extrahepatic bile duct cancer, and received gemcitabine-based neoadjuvant chemoradiation therapy after histological or cytological confirmation of bile duct cancer. After the completion of NACRT, pancreaticoduodenectomy with extensive regional lymphadenectomy was performed. We collected the following data at the diagnosis and after NACRT of white blood cell count, neutrophil count, lymphocyte count, hemoglobin, platelet count, and the serum levels of total protein, albumin, blood urea nitrogen (BUN), creatinine and C reactive protein (CRP). The prognostic nutrition index (PNI) and the neutrophil-to-lymphocyte ratio (NLR) were calculated according to these results. The PNI was calculated using the following equation: PNI = 10 x serum albumin (mg/dl) + 0.005 x total lymphocyte count. In the present study, the cutoff values for the PNI and NLR were 40 and 2.5, respectively.

We retrospectively collected information related to adverse events during NACRT and the complications after surgery. Adverse events during NACRT were graded according to the Common Terminology Criteria for Adverse Events version 4.0, and postoperative complications were defined as any complication classified as grade 2 (requiring pharmacological treatment) or higher, according to the Clavien-Dindo classification (4).

The protocol of gemcitabine-based chemoradiation therapy has reported previously (1). In brief, the intravenous administration of gemcitabine (1,000 mg/m²) was concurrently initiated on days 1, 8, and 15 during each four-week cycle, and repeated for two or three cycles. 3 dimensional radiation was administered at a total dosage of 50-60 Gy with a daily fraction of 2-2.4 Gy 5 times per week, which targeted the primary distal bile tumor with the surrounding lymph nodes it, the para-aortic region, and the retroperitoneal soft tissue. All protocols were conducted after obtaining written informed consent from all patients in accordance with the approved procedure at our hospital. Patients eligible for enrollment were confirmed before the initiation of NACRT. The criteria for the patients were as follows: resectable distal bile duct cancer, subserosal or deeper tumor invasion, and no evidence of distant metastases. The introduction of adjuvant chemotherapy and the regimens of anticancer drugs were decided based on the evaluation of the attending physicians and the patient's performance status. Among the 16 patients, 6 (37%) received gemcitabine, and 3(19%) received TS-1 after surgery. The adjuvant S-1 group received 4 cycles of oral TS-1 chemotherapy at the dose of 40 mg/m² twice daily for 4 weeks, followed by 2 weeks of rest.

The skeletal muscle area, visceral fat area and subcutaneous fat area were assessed by computed tomography before and after NACRT using the Zio station 2 (Ziosoft, Inc.) software program (Fig. 1). The skeletal muscle area was measured as the cross-sectional area of the total skeletal muscle area at the level of middle portion of the 3rd lumbar vertebra by manual tracing. The visceral fat and subcutaneous fat area were also measured at the level of middle portion of the 3rd lumbar vertebra by applying a threshold with an attenuation range of -60 to -120 Hounsfield units. The skeletal muscle index (SMI) was calculated with the following equation: (cm²/m²) = skeletal muscle area (cm²)/height (m²). Sarcopenia was defined as an SMI of 42 cm²/m² in males and 38 cm²/m² in females according to Japan Society of Hepatology guidelines for sarcopenia in liver disease (1st edition) (5).

The data were analyzed using JMP^® 13 (SAS Institute Inc.). Categorical variables were reported as numbers and percentages, while continuous variables were reported as the median and range. The Fisher's exact test was used for the comparison of categorical variables, and the Mann-Whitney U test was used for the comparison of continuous variables. The Wilcoxon signed-rank test was used for the comparison between paired samples. Pearson's correlation analysis was performed to analyze the correlation between SMI and total fat area. Survival rates were calculated using the Kaplan-Meier methods and compared using a log-rank test. P-values of <0.05 were considered to indicate statistical significance.

All 16 patients completed NACRT followed by pancreaticoduodenectomy without mortality. The median period from NACRT to operation was 100 days (range, 70-121). Six patients (37%) experienced grade ≥3 adverse events. Grade ≥2 complications were observed in 10 patients (62%). The most common complication was postoperative pancreatic fistula (POPF) which occurred in six patients (37%) (Table I).

The results of laboratory tests, immunological and nutritional indices, and the body composition of before and after NACRT are shown in Table II. There was no significant change in the neutrophil count, platelet count, total protein, albumin, BUN, creatinine, CRP from before to after NACRT. The lymphocyte count (P=0.0076) and hemoglobin level (P=0.001) significantly decreased after NACRT. The median PNI and NLR were 42.7 (range, 30.8-50.3) and 1.89 (range, 1.06-5.07) before NACRT, and 40.8 (range, 32.4-50.1) and 2.46 (range, 1.0-5.12) after NACRT. There was no significant difference in the pre-NACRT and post-NACRT values.

The median SMI in males was 44.6 cm²/m² (range, 26.2-57.6) before NACRT and 44.4 cm²/m² (range, 29.6-51.2) after NACRT. The median SMI in females was 30.5 cm²/m² (range, 27.2-33.6) before NACRT, and 31.5 cm²/m² (range, 28.5-39.0) after NACRT. The total SMI before and after NACRT did not differ to a statistically significant extent (Fig. 2A). In male patients, there was a significant correlation between total fat area and SMI after NACRT (R=0.602 and P=0.049). Nine (56%) of the 16 patients were identified as sarcopenic before NACRT. Eight (50%) patients met the criteria for sarcopenia after NACRT. Among all nine patients with sarcopenia before NACRT, only one who had sarcopenia before NACRT recovered after NACRT, whereas the other eight patients remained sarcopenic after NACRT. Only two patients required a reduction in the dosage of NACRT, including one with sarcopenia. After NACRT, the median BMI, subcutaneous fat area and total fat area at the level of the middle portion of the 3rd lumbar vertebra were smaller in comparison to before NACRT; however, the differences were not statistically significant (Fig. 2B).

POPF, intra-abdominal abscess, chylous ascites, diarrhea, and delayed gastric empty were observed in this study. We also focused on POPF because it is one of the most important and frequent complications after pancreaticoduodenectomy. The patients with POPF (ISGPF B or C) had a significantly greater SMI and total fat area than patients without POPF (P=0.019, and P=0.007, respectively). There was no significant association between the incidence of postoperative complications and the NLR, PNI, or sarcopenia after NACRT (Tables III and IV).

Patients with sarcopenia had significantly shorter disease-free survival in comparison to those without sarcopenia (P=0.025). The 3-year overall survival rate of patients without sarcopenia was 100%, while that of patients with sarcopenia was 71%; however, the difference was not statistically significant (Fig. 3). The SMI, total fat area, PNI, and NLR were not correlated with the overall and disease-free survival rates. Adjuvant chemotherapy was introduced in 9 (56%) of 16 patients, and only 2 needed to have the dosage of adjuvant chemotherapy reduced, while 1 required cessation of therapy. There was no significant difference between receiving a reduced dose of adjuvant chemotherapy and the presence of sarcopenia (Table V). The induction rate of adjuvant chemotherapy was not significantly different between the patients with and without sarcopenia and was also not associated with the disease-free survival (DFS) or overall survival (OS).