Related Experiment Video
Updated: Aug 2, 2025

Competing-Risk Nomogram for Predicting Cancer-Specific Survival in Multiple Primary Colorectal Cancer Patients after Surgery
Published on: September 27, 2024
A Belgian Population-Based Study Reveals Subgroups of Right-sided Colorectal Cancer with a Better Prognosis Compared
Katleen Janssens1,2, Erik Fransen1,3, Guy Van Camp1,2
1Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Prins Boudewijnlaan 43, Edegem, Belgium.
Background:
Patients with left-sided colorectal cancer (L-CRC) are known to have a significantly better prognosis than those with right-sided CRC (R-CRC). It has been hypothesized that RAS, BRAF mutations, or deficient mismatch repair status (MMR) might be responsible for the prognostic effect of primary tumor location (PTL). This study aims to evaluate the prognostic effect of PTL in the Belgian population and to determine the role of biomarkers (MMR, BRAF, and RAS status) in this effect.
Patients And Methods:
We performed a retrospective analysis of Belgian Cancer Registry data. First, we studied the prognostic effect of PTL on 5-year relative survival of 91,946 patients diagnosed with CRC (all stages) from 2004-2015. Second, we investigated the interaction between biomarkers and the prognostic effect of PTL in 1818 patients diagnosed with stage IV CRC in 2014-2015.
Results:
L-CRC was associated with a significantly better 5-year relative survival compared to R-CRC in all stages and ages combined (68.4%, 95% CI, 67.7-69.1% vs 65.6%, 95% CI, 64.7-66.4%). Also, when stratified by age, sex, and stage, the prognosis of L-CRC was better compared to R-CRC in most subgroups. Only in stage II and certain subgroups of elderly patients, the opposite was observed. Furthermore, our data showed that none of the biomarkers had a significant interaction with the effect of PTL on survival.
Conclusion:
This population-based study confirms that L-CRC is associated with significantly better relative survival compared to R-CRC, in all stages and ages combined. Furthermore, in stage IV L-CRC is associated with a longer survival than R-CRC, regardless of MMR, RAS, and BRAF status.
More Related Videos
07:13Comparison of Predictive Performance of Three Lymph Node Staging Systems in Colorectal Signet Ring Cell Carcinoma Based on Machine Learning Model
Published on: April 18, 2025
08:26Clinical Application of Single-Surgeon, Three-Port, Laparoscopic Resection for Colorectal Cancer with Natural Orifice Specimen Extraction
Published on: March 24, 2023