Risk factors for occult metastasis detected by inflammation-based prognostic scores and tumor markers in biliary tract cancer

BACKGROUND Radiological detection of small liver metastasis or peritoneal metastasis is still difficult, and some patients with biliary tract cancer (BTC) are unresectable after laparotomy. Staging laparoscopy may help avoid unnecessary laparotomy. However, which category of BTC is amenable with staging laparoscopy remains unclear. AIM To clarify the risk factors for occult metastasis in patients with BTC. METHODS Medical records of patients with BTC who underwent surgery at our institution between January 2008 and June 2014 were retrospectively reviewed. The patients were divided into two groups, according to resection or exploratory laparotomy (EL). Preoperative laboratory data, including inflammation-based prognostic scores and tumor markers, were compared between the two groups. Prognostic importance of detected risk factors was also evaluated. RESULTS A total of 236 patients were enrolled in this study. Twenty-six (11%) patients underwent EL. Among the EL patients, there were 16 cases of occult metastasis (7 liver metastases and 9 abdominal disseminations). Serum carcinoembryonic antigen level, carbohydrate antigen 19-9 level, neutrophil- lymphocyte ratio and modified Glasgow prognostic score were significantly higher in the EL group than in the resected group, and these factors were prognostic. Among these factors, carcinoembryonic antigen > 7 ng/mL was the most useful to predict occult metastasis in BTC. When patients have more than three of these positive factors, the rate of occult metastasis increases. CONCLUSION Inflammation-based prognostic scores and tumor markers are useful in detecting occult metastasis in BTC; based on these factors, staging laparoscopy may reduce the rate of EL.