C-reactive protein for the early prediction of anastomotic leak after esophagectomy in both neoadjuvant and non-neoadjuvant therapy case: a propensity score matching analysis

Background: Anastomotic leak is one of most significant causes of mortality after esophagectomy. Therefore, it is clinically valuable to detect anastomotic leak early after esophagectomy in esophageal cancer. The purpose of this study is to investigate the associations between routine postoperative laboratory findings and anastomotic leak and to analyze the laboratory findings to find out an independent predictive marker for anastomotic leak. In addition, this study compares cases treated with neoadjuvant therapy (NT) and those without (non-NT). Methods: We retrospectively assessed the medical records of 201 consecutive cases that met this study's criteria from January 2009 to December 2016. All patients underwent curative and complete esophagectomy for intra-thoracic esophageal cancer. We compiled and analyzed routine laboratory findings from the day before surgery to the eighth postoperative day on a daily basis. Routine laboratory tests consisted of 26 separate tests, including complete blood cell counts, blood chemistries, as well as erythrocyte sedimentation rate and C-reactive protein (CRP). Barium esophagogram with chest computed tomography (CT) was performed on the seventh postoperative day to evaluate the presence of an anastomotic leak. Results: A total of 45 of 201 patients underwent NT. Anastomotic leaks were found in 23 (11.4%) of 201 patients (8 patients in NT and 15 patients in non-NT). White blood cell (WBC) from the second postoperative day (P=0.031, P=0.006, P=0.007, P=0.007, P=0.041, and P=0.003, respectively) and CRP from the third postoperative day (P=0.012, P<0.001, P=0.014,P<0.001, P=0.001, and P= 0.006, respectively) were associated with anastomotic leak in non-NT; however, only CRP on the third, fifth, sixth, and seventh postoperative days (P=0.041, P=0.037, P=0.002, and P=0.003, respectively) was associated with anastomotic leak in NT. The CRP level on the third postoperative day was a significant independent predictive marker of anastomotic leak (P=0.041, odd ratio (OR) 1.056, 95% confidential interval (CI): 1.002-1.113) and had a significant diagnostic cutoff value for the development of anastomotic leak (non-NT: cutoff value 17.12 mg/dL, sensitivity 69.2%, specificity 78.1%, P<0.001, area 0.822; NT: cutoff value 16.42 mg/dL, sensitivity 80.0%, specificity 70.0 %, P=0.042, area 0.7104). Conclusions: There were divergent laboratory findings reflective of anastomotic leak between patients who underwent NT and those who did not. The CRP level on the third postoperative day had a significant cutoff value for early detection of anastomotic leak after esophagectomy in both NT and non-NT groups.