Figure 1.

Flow diagram of the study cohort. Out of the 648 patients with PanNENs, 169 patients with metastatic PanNETs were included for further eligibility evaluation. Then 103 patients had paired primary tumors and metastases with an available Ki67 index were identified as the study cohort, and the remaining 66 patients were identified as the bias-control group. The study cohort consisted of 91 patients underwent resection and 12 patients experienced biopsy. In resection cohort, 74 and 17 patients had synchronous and metachronous metastases, respectively. And biopsy cohort consisted of 12 patients with synchronous metastases.