By Dr Ang Hong Shien, Medical Officer, NCSM
Colorectal cancer (CRC) is one of the most prevalent cancers worldwide, ranking as the third most diagnosed cancer and the second leading cause of cancer-related deaths. It affects the colon or rectum, integral parts of the digestive system, with an increasing incidence, particularly among younger populations. This feature explores key aspects of CRC, including risk factors, screening, treatment advancements, and emerging trends in research and prevention.
Understanding the Risk Factors
Colorectal cancer develops due to a complex interplay of genetic, environmental, and lifestyle factors. While age remains a significant risk factor—most cases are diagnosed in individuals over 50—an alarming rise in CRC incidence among those under 50 has prompted calls for earlier screening and further research.
Individuals with a family history of colorectal cancer (CRC) or inherited syndromes such as Lynch syndrome and familial adenomatous polyposis (FAP) have a higher risk of developing the disease. Lifestyle factors also play a significant role, with diets high in red and processed meats, low fiber intake, smoking, excessive alcohol consumption, and sedentary behavior all contributing to increased CRC risk. Additionally, obesity and metabolic syndrome can lead to chronic inflammation, which may promote cancer development. Furthermore, individuals with inflammatory bowel diseases (IBD) such as Crohn’s disease and ulcerative colitis face a heightened risk due to prolonged inflammation of the intestinal lining.
The Critical Role of Screening and Early Detection
Screening plays a crucial role in reducing CRC mortality by identifying precancerous polyps or early-stage cancers that are more treatable. However, despite its effectiveness, screening adherence remains a challenge due to lack of awareness, fear of procedures, and limited access to healthcare.
Colonoscopy is considered the gold standard for colorectal cancer screening, as it allows for both the detection and removal of polyps in a single procedure. Non-invasive options include the fecal occult blood test (FOBT), which detects hidden blood in stool, and stool DNA testing, which combines FOBT with DNA markers to enhance detection accuracy. Additionally, alternative imaging techniques such as flexible sigmoidoscopy and CT colonography provide visualisation of the colon, offering further screening options for individuals at risk.
Advances in Treatment Strategies
Treatment for colorectal cancer depends on the tumor’s stage and location. Significant advancements in colorectal cancer treatment have improved patient outcomes and expanded therapeutic options. Liquid biopsies, a non-invasive technique, analyse circulating tumor DNA (ctDNA) to enable early detection, monitor treatment response, and identify recurrences. Minimally invasive surgical approaches, such as laparoscopic and robotic-assisted techniques, have also enhanced patient recovery by reducing complications and shortening hospital stays.
Additionally, targeted therapies like cetuximab and bevacizumab specifically attack molecules involved in cancer growth, paving the way for more personalised treatment options. Immunotherapy has emerged as another breakthrough, with immune checkpoint inhibitors like pembrolizumab showing particular promise in treating advanced CRC cases with microsatellite instability-high (MSI-H) tumors. These advancements collectively represent a shift toward more precise, effective, and less invasive treatment strategies for colorectal cancer.
Emerging Research and Innovations
Ongoing research is providing deeper insights into colorectal cancer, offering hope for more effective treatments and preventive measures.
Research into colorectal cancer is rapidly evolving, offering promising insights into prevention and treatment. The rise in early-onset colorectal cancer has led scientists to investigate potential causes such as gut microbiota changes, dietary shifts, and environmental factors, while also considering whether screening guidelines should be adjusted for younger populations. The role of the gut microbiome in CRC development is another growing area of interest, with studies indicating that microbial imbalances may contribute to inflammation and tumor progression.
Additionally, precision medicine is advancing with the use of liquid biopsies, which allow real-time monitoring of tumor dynamics and enable more personalised treatment strategies. Artificial intelligence (AI) is also playing a transformative role in CRC detection, using enhanced imaging analysis and risk prediction models to improve screening accuracy.
Meanwhile, lifestyle modifications remain a key preventive strategy, with public health campaigns emphasising the benefits of a healthy diet, regular exercise, and weight management. The Mediterranean diet, rich in fruits, vegetables, and whole grains, has been particularly associated with a reduced risk of CRC.
Challenges and Future Directions
Despite these advances, several challenges remain. Socioeconomic and racial disparities, along with geographic limitations, impact access to colorectal cancer screening and treatment, leading to poorer outcomes for certain populations. Additionally, some patients develop resistance to chemotherapy and targeted therapies, highlighting the urgent need for novel treatment approaches. The global burden of CRC is also rising, particularly in low- and middle-income countries, where limited resources for screening and treatment contribute to late-stage diagnoses and poorer survival rates.
Addressing these challenges requires a comprehensive approach, including increased research funding, improved healthcare infrastructure, and international collaboration to share knowledge and resources.
Conclusion
Colorectal cancer remains a significant public health concern, but advancements in screening, treatment, and research offer hope for better patient outcomes. Early detection through screening, combined with lifestyle modifications and innovative therapies, can substantially reduce the burden of this disease. As scientists continue uncovering new insights into CRC causes and mechanisms, the focus must remain on prevention, equitable access to care, and personalised treatment strategies. By tackling these critical issues, we move closer to a future where colorectal cancer is no longer a leading cause of cancer-related deaths.
1. National Cancer Institute. (2023). Colorectal Cancer Prevention (PDQ®). Retrieved from https://www.cancer.gov
2. Dekker E, Tanis PJ, Vleugels JLA, Kasi PM, Wallace MB. Colorectal cancer. Lancet. 2019 Oct 19;394(10207):1467-1480. doi: 10.1016/S0140-6736(19)32319-0. PMID: 31631858.
3. Liu, B., Zhou, H., Tan, L. et al. Exploring treatment options in cancer: tumor treatment strategies. Sig Transduct Target Ther 9, 175 (2024). https://doi.org/10.1038/s41392-024 01856-7
4. Wei, J., Li, W., Zhang, P. et al. Current trends in sensitizing immune checkpoint inhibitors for cancer treatment. Mol Cancer 23, 279 (2024). https://doi.org/10.1186/s12943-024 02179-5
5. Wu CW, Lui RN. Early-onset colorectal cancer: Current insights and future directions. World J Gastrointest Oncol. 2022 Jan 15;14(1):230-241. doi: 10.4251/wjgo.v14.i1.230. PMID: 35116113; PMCID: PMC8790420.
6. Rebersek, M. Gut microbiome and its role in colorectal cancer. BMC Cancer 21, 1325 (2021). https://doi.org/10.1186/s12885-021-09054-2
7. Anil Kumar, Nikhil Aravind, Tayiba Gillani, Deepak Kumar, Artificial intelligence breakthrough in diagnosis, treatment, and prevention of colorectal cancer – A comprehensive review, Biomedical Signal Processing and Control, Volume 101, 2025, 107205, ISSN 1746-8094, https://doi.org/10.1016/j.bspc.2024.107205.
8. Pandey S, Yadav P. Liquid biopsy in cancer management: Integrating diagnostics and clinical applications. Pract Lab Med. 2024 Dec 24;43:e00446. doi: 10.1016/j.plabm.2024.e00446. PMID: 39839814; PMCID: PMC11743551.
