Mo1706 OBSTRUCTIVE COLON CANCER AT ENDOSCOPY AS AN INDEPENDENT RISK PREDICTOR OF ADVANCED TUMOR STAGE AND REDUCED SURVIVAL

Abstract

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. 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). Data on patients' demographics and ethnicities were documented. Patients with a finding of obstructive tumors at endoscopy were compared to a control group of patients 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 and grade at diagnosis. 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%, P<0.01) (Table 1). 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). In multivariate analysis obstructive tumor finding was associated with increased risk of advanced CRC stage at diagnosis (odds ratio=3.018, p<0.0001 and 95%CI=1.951-4.670). A prominent difference of overall survival curves was also noted as obstructive colon cancer was 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) survival (Figure 1). 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.View Large Image Figure ViewerDownload Hi-res image Download (PPT)