OBSTRUCTIVE COLON CANCERS AT ENDOSCOPY ARE ASSOCIATED WITH ADVANCED TUMOR STAGE AND POOR PATIENT OUTCOME

Aims It is still debatable whether a colorectal cancer tumor size affects patients´ prognosis and outcome. A more clinically relevant and frequently encountered scenario is the presence of subclinical obstructive mass during endoscopic exam hindering the passage of endoscope and precluding complete exam. The significance and implications of this finding were not fully investigated, and will be addressed in this study.

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

Results 144 patients had obstructive colonic tumors while 254 had non-obstructive tumors and constituted the control group. Obstructive colon cancer group was significantly associated with advanced tumor stage (Stage 3 or above) at diagnosis compared to the non-obstructive controls (69% Vs. 42%, OR = 3.018, 95%CI = 1.951–4.670; P < 0.01). Likewise, in terms of histologic grade, more patients in the obstructive group were classified as moderate to poorly differentiated compared to controls (64.5 % vs. 38.4%; P < 0.001). Patients with obstructive tumors were significantly associated with decreased one (77.8% vs. 86%; P = 0.01), three (63.6% vs.77.4%; P < 0.01) and five years (53.4% vs. 67.3% vs.; P < 0.01) overall survival. Increased overall mortality was observed in survival curves of patients with obstructive tumors along all follow-up period compared to non-obstructive controls.

Conclusions Even in the absence of clinical sequela, obstructive colorectal cancer 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.