Impact of Comorbidities on Treatment Outcomes Among Saudi Patients With Colorectal Cancer: A Retrospective Study.

BACKGROUND: Colorectal cancer is a leading cause of cancer-related morbidity and mortality worldwide and is among the most common malignancies in Saudi Arabia. The high prevalence of chronic noncommunicable diseases in the Saudi population raises concern regarding the impact of comorbidities on colorectal cancer outcomes. However, local data evaluating the prognostic significance of comorbidity burden remain limited. METHODS: We conducted a retrospective cohort study across government health cluster hospitals in Saudi Arabia. Adult patients with histologically confirmed colorectal cancer diagnosed between January 2015 and December 2022 were included. Demographic, clinical, tumor-related, and treatment data were extracted from electronic medical records. Comorbidity burden was assessed using the Charlson Comorbidity Index (CCI). Patients were stratified by comorbidity status and CCI score (<3 vs. ≥3). The primary outcome was overall survival; secondary outcomes included disease-free survival, cancer-related mortality, postoperative complications, and treatment completion. Survival analyses were performed using Kaplan-Meier methods and Cox proportional-hazards models. RESULTS: A total of 312 patients were included (mean age: 61.8±11.9 years; 59.9% male). At least one comorbidity was present in 214 patients (68.6%), and 74 patients (23.7%) had a CCI score of 3 or higher. Hypertension (47.1%) and diabetes mellitus (42.3%) were the most common comorbidities. Advanced disease (stage III-IV) was observed in 215 patients (68.9%). Patients with higher comorbidity burden were less likely to undergo curative-intent surgery (60.8% vs. 83.2%) or complete adjuvant chemotherapy (35.1% vs. 62.6%) and experienced higher rates of postoperative complications (37.8% vs. 16.4%). Five-year overall survival was significantly lower among patients with comorbidities than those without comorbidities (48.2% vs. 66.7%, p=0.002), and disease-free survival was similarly reduced (42.6% vs. 59.1%, p=0.01). CONCLUSIONS: Comorbidities are highly prevalent among Saudi patients with colorectal cancer and are associated with reduced treatment delivery and significantly poorer survival outcomes. Systematic assessment and proactive management of comorbidity burden should be integrated into colorectal cancer care to improve prognosis and optimize treatment outcomes.