Systematic review of the clinical significance of lymph node micrometastases of pancreatic adenocarcinoma following surgical resection

Objectives The aim of this study is to perform a systematic review of the clinical impact of lymph node micrometastasis in pancreatic adenocarcinoma following surgical resection. Methods A systematic review was conducted and published literature were searched using “pancreas or pancreatic” and “cancer or carcinoma or neoplasm”, and “micrometastasis or micrometastses” in the PubMed, EMBAE, and Web of Science. Results Thirteen publications with 726 patients and 3701 lymph nodes were included in this systematic review. The detection method was immunohistochemical stains or polymerase chain reaction. The pooled proportion of patients with positive lymph node micrometastasis was 43.1% (95% Confidence interval (CI) 0.254–0.628). The pooled proportion of positive lymph node micrometastasis (number of positive lymph node micrometastasis/total number of lymph nodes examined) was 10.8% (95% CI 4.8–22.6). Among the conventional H &E negative patients, the reported 5-year survival rates of the patients without lymph node micrometastases vs. those with lymph node micrometastases in the ranged from 50% to 61% and from 0% to 36%, respectively Patients with lymph node micrometastasis showed poorer survival (Hazard ratio 4.29, 95% CI 1.27–14.41). Conclusions The presence of lymph node micrometastasis is associated with poorer survival. Lymph node micrometastasis is applicable to stratify the risk of recurrence and the need for adjuvant therapy of post-resection patients with pancreatic adenocarcinoma in the conventional H & E lymph node negative patients.