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

## TL;DR

This study shows that comorbidities in Saudi colorectal cancer patients lead to worse treatment outcomes and lower survival rates.

## Contribution

The study provides new local evidence on how comorbidities affect colorectal cancer outcomes in Saudi Arabia.

## Key findings

- Patients with higher comorbidity burden had lower rates of curative surgery and chemotherapy completion.
- Comorbidities were linked to significantly reduced five-year overall and disease-free survival rates.
- Hypertension and diabetes were the most common comorbidities among the studied patients.

## Abstract

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.