S180 Rectal Bleeding as a Symptom of Advanced Colorectal Cancer Is Associated With Left-Sided Colorectal Cancer and Improved Survival

Abstract

Introduction: Rectal bleeding (RB) is a symptom of colorectal cancer (CRC) that often prompts endoscopic investigation. The outcomes of RB in the setting of CRC have not been well described. We investigated the outcomes of patients diagnosed with stage IV CRC after presenting with RB. Methods: We retrospectively analyzed patients ages 18 years and older diagnosed with Stage IV CRC from 2011 to 2017 in our academic, safety-net hospital. Patients were excluded if they were not diagnosed via diagnostic colonoscopy. Patients were stratified based on RB at presentation. Location of tumors were categorized as right-sided colorectal cancer (RCRC) and left-sided colorectal cancer (LCRC). RCRC included those located from the cecum to the proximal two-thirds of the transverse colon. LCRC included those located from the distal one-third of the transverse colon to the rectum. Results: Sixty-nine patients met the inclusion criteria. General characteristics are shown in Table. Those without RB had significantly higher Charlson Comorbidity Index (CCI) scores (p < 0.05). The average time from presentation to endoscopy in those with RB compared to those without RB were 0.9 + 1.5 months and 1.2 + 3.3 months, respectively (p = 0.53). All thirty-five patients with RB had LCRC. For those without RB, eighteen had RCRC and sixteen had LCRC. There were no differences in times to surgery (p = 0.09), systemic therapy (p = 0.27), or any treatment (p = 0.14). Median survival in those with RB was 1377 days and those without RB was 358 days. Using the Cox proportional hazards model with CCI, gender, and race as covariates for multivariate analysis, the average length of survival remained significantly higher in patients with RB (p < 0.01, HR 0.43, 95% CI 0.23-0.80) (Figure). Conclusion: RCRC and LCRC have been documented to have different morphological and molecular characteristics, with RCRC often being described as more aggressive than LCRC. In our study, all patients who presented with RB had LCRC and more than half of the patients without RB had RCRC. The absence of RB was associated with increased mortality after controlling for age, comorbidities, gender, and race. Furthermore, there were no differences in time to either endoscopy or treatment. In conclusion, RB in CRC may be more indicative of left-sided disease which may be associated with a less aggressive disease course. However, more research is required to fully understand the association between RB and clinical outcomes.Figure 1.: Survival curve using the Cox proportional hazards model with CCI, race, and gender as covariates for multivariate analysis. Red line: Rectal Bleeding. Black line: No Rectal Bleeding. p < 0.01, HR: 0.43, 95% CI: 0.23 - 0.80 Table 1. - General characteristics, time from presentation to endoscopy, median survival, and times to treatment in patients with stage IV colorectal cancer Rectal Bleeding No Rectal Bleeding Significance Number of Patients 35 34 Age at Diagnosis 57.9 + 13.0 62.2 ± 13.8 n.s. Sex Male 20 (57.1%) 17 (50.0%) n.s. Female 15 (42.9%) 17 (50.0%) Race White 15 (42.9%) 12 (35.3%) n.s. Black 19 (54.3%) 20 (58.8%) Other 1 (2.9%) 2 (5.9%) Charlson Comorbidity Index 5.6 ± 2.3 6.9 ± 2.0 < 0.05 Time from presentation to endoscopy (months) 0.9 ± 1.5 1.2 ± 3.3 n.s. Median Survival (days) 1377 358 < 0.01 Time to first treatment (months) 2.7 ± 4.8 1.3 ± 1.8 n.s. Time to surgery (months) 4.2 ± 3.2 2.2 ± 3.0 n.s. Time to systemic treatment (months) 3.0 ± 4.7 1.8 ± 1.8 n.s.