Differences in Metastatic Pattern in Patients Presenting With or Without Obstructing Colorectal Cancer: A Retrospective Observational Study of 2595 Patients

Background Little is known about metastatic patterns in patients with obstructing colorectal cancer (CRC). Objective The aim of this study was to determine if metastatic patterns in patients with CRC differ between patients with or without obstruction. Methods This single-center, observational, retrospective cohort study includes patients who underwent surgery for CRC between 2004 and 2015 in our hospital. Patients were divided into two groups—patients with or without obstructing CRC. All anatomic sites of distant metastases were reported. Differences in synchronous and metachronous metastases were compared between both groups. Results A total of 2595 patients were included for analysis, of whom 315 (12%) presented with obstructing CRC. Synchronous metastases were diagnosed in 483 patients (19%). Patients with obstructing CRC and synchronous metastases, were diagnosed with peritoneal metastases more often than patients without obstruction (37% vs. 16%; p < 0.01). With regard to the location of the tumor, obstructing right-sided CRC patients were diagnosed with peritoneal metastases more often than patients without obstruction (52% vs. 21%; p < 0.01). Additionally, metachronous metastases were found significantly more often in patients with obstructing CRC (27%) compared with patients without obstruction (15%; p < 0.01). Conclusions Patients with obstructing CRC have more advanced tumor stage compared with patients without obstructing CRC. Synchronous peritoneal metastases are more often encountered in patients with obstructing CRC compared with patients without obstruction. This difference is due to the raised presence of synchronous peritoneal metastases in patients with obstructed right-sided colonic cancer. Furthermore, metachronous metastases are more often found in patients with obstructing CRC.