Primary tumor site is associated with response to BT in mCRC. Right-sided primary tumor location is associated with higher mortality regardless of BT type. In patients with wild-type KRAS tumors, treatment with cetuximab benefited only those with left-sided mCRC and was associated with significantly poorer survival among those with right-sided mCRC. Our results underscore the importance of stratification by tumor site for current treatment guidelines and future clinical trials.

Colorectal cancer (CRC) is the most common cancer in males and third in females in Saudi Arabia, with the majority (66%) diagnosed at a late stage. We evaluated the effect of marital status on stage at diagnosis and CRC survival. We hypothesized that married patients would be more likely to present at an early stage and have higher survival than unmarried patients. The Ministry of National Guard-Health Affairs (MNG-HA) cancer registry was used to identify patients diagnosed with CRC from 2009 to 2017. A competing risk analysis was performed to assess the 5-year CRC-specific survival, adjusting for potential confounders. The Kaplan–Meier method and the Cox regressions were used to assess survival. Two-thirds (76.50%) of the 936 CRC patients were married, 11.64% were unmarried, and 11.86% had an unknown marital status. With multiple imputation-based analysis, the multivariate analysis indicated that unmarried patients were 52% more likely to present at an advanced stage [adjusted odds ratio (aOR) 1.52; 95% CI 1.33–1.73], and had a 30% higher risk of death due to CRC compared to the married patients (aHR 1.30; CI 1.17, 1.44). Future CRC screening and survivorship programs should assess the needs of the vulnerable unmarried population. Interventions supporting the early detection of CRC in this population may be beneficial in the long term and lead to improved cancer outcomes.

Background Colorectal cancer (CRC) is the most diagnosed cancer among males and third among females in Saudi Arabia, with up to two-third diagnosed at advanced stage. The objective of our study was to estimate CRC survival and determine prognostic factors. Methods Ministry of National Guard- Health Affairs (MNG-HA) registry data was utilized to identify patients diagnosed with CRC between 2009 and 2017. Cases were followed until December 30th, 2017 to assess their one-, three-, and five-year CRC-specific survivals. Kaplan-Meier method and Cox proportional hazard models were used to assess survival from CRC. Results A total of 1012 CRC patients were diagnosed during 2009–2017. Nearly, one-fourth of the patients presented with rectal tumor, 42.89% with left colon and 33.41% of the cases were diagnosed at distant metastasis stage. The overall one-, three-, and five-year survival were 83, 65 and 52.0%, respectively. The five-year survival was 79.85% for localized stage, 63.25% for regional stage and 20.31% for distant metastasis. Multivariate analyses showed that age, diagnosis period, stage, nationality, basis of diagnosis, morphology and location of tumor were associated with survival. Conclusions Findings reveal poor survival compared to Surveillance, Epidemiology, and End Results (SEER) population. Diagnoses at late stage and no surgical and/or perioperative chemotherapy were associated with increased risk of death. Population-based screening in this population should be considered.