Obstructive colon cancers at endoscopy are associated with advanced tumor stage and poor patient outcome. A...

The detection of obstructive colorectal cancer (CRC) masses during endoscopic examination hindering the passage of endoscope and precluding complete examination is not uncommon. The significance and implications of this finding on patients' prognosis and outcomes were not fully investigated and will be addressed in this study.

In this retrospective cohort study, we reviewed endoscopy, surgery, pathology and oncology reports of patients diagnosed with CRC over a 10-year period (2007-2016). We compared surgical stages, histologic grades and overall survival between patients with subclinical obstructive tumors at endoscopy to those with nonobstructive tumors. We performed multivariate analysis to identify independent risk factors associated with advanced CRC stage at diagnosis.

A total of 144 patients had obstructive colonic tumors while 254 had nonobstructive tumors and constituted the control group. Obstructive CRC group was significantly associated with advanced tumor stage at diagnosis (69 vs. 42%, OR = 3.018, 95% CI, 1.951-4.670; P < 0.01) and had prominently higher rates of moderate to poorly differentiated tumors (64.5 vs. 38.4%; P < 0.001) when compared to non-obstructive controls. Patients with obstructive tumors were significantly associated with decreased five years overall survival (53.4 vs. 67.3% vs.; P < 0.01). Increased overall mortality was observed in survival curves of patients with obstructive tumors along all follow-up periods.

Even in the absence of clinical sequela, obstructive CRC at endoscopic level may be associated with higher stage at diagnosis and reduced overall survival. Further prospective studies are warranted to confirm these findings and address their implication on patients' management.