Colorectal Cancer: How Family History Affects Your Risk
Colorectal cancer, commonly known as bowel cancer, is a major health concern in Singapore, ranking among the most frequent cancers diagnosed each year. While lifestyle factors such as diet, physical activity, and smoking habits influence risk, family history and genetic predispositions play a crucial role in determining an individual’s likelihood of developing colorectal cancer. Understanding how hereditary factors impact this risk can help you and your healthcare team take proactive steps in prevention, early detection, and treatment.
What Is Colorectal Cancer and Its Genetic Links?
Colorectal cancer begins in the colon or rectum, often developing from benign polyps that may become cancerous if not detected and treated early. About 10% of colorectal cancer cases are linked to inherited genetic syndromes, while up to 20% of patients have a family history suggestive of hereditary risk, even if the exact genetic mutation is unidentified yet.
Two major hereditary syndromes significantly increase colorectal cancer risk:
- Lynch Syndrome (Hereditary Nonpolyposis Colorectal Cancer or HNPCC): The most common genetic syndrome associated with colorectal cancer, caused by mutations in genes responsible for DNA repair such as MLH1, MSH2, MSH6, PMS2, and EPCAM. Individuals with Lynch syndrome typically develop cancer at a younger age—often before 50—and have elevated risks for other cancers like endometrial and ovarian cancer.
- Familial Adenomatous Polyposis (FAP): A syndrome marked by the development of hundreds to thousands of polyps in the colon and rectum, caused by mutations in the APC gene. Without early intervention, nearly all individuals with FAP will develop colorectal cancer, often at a young age.
Even in the absence of these syndromes, having close family members (parents, siblings) diagnosed with colorectal cancer increases one’s risk significantly. This familial risk means you may benefit from earlier and more frequent screening.
The Importance of Family History
A detailed family cancer history provides vital clues for cancer risk assessment. If you have relatives diagnosed with colorectal cancer, especially if diagnosed young or if multiple family members are affected, you may be at higher risk. Singaporean experts recommend that individuals with a strong family history start screening earlier—often from age 40 or 10 years earlier than the youngest affected family member.
Colorectal Cancer Screening in Singapore
Singapore’s national guidelines encourage colorectal cancer screening starting at age 50 for average-risk individuals using fecal immunochemical tests (FIT), with colonoscopy follow-up for positive results. However, those with hereditary risks or family history may require personalized screening plans, including earlier and more frequent colonoscopies. Genetic counseling and testing for hereditary syndromes can guide these plans and help identify at-risk family members.
Where to Seek Help and Genetic Counseling
Specialist colorectal clinics in Singapore, such as the Capstone Colorectal Surgery Centre and services at the National Cancer Centre Singapore (NCCS), provide comprehensive genetic counseling and testing. These resources assist patients and families in understanding their hereditary risk, managing surveillance, and making informed decisions about preventive measures, including possible prophylactic surgeries.
Conclusion
Family history and inherited genetic conditions substantially influence colorectal cancer risk. Being aware of your family’s cancer history and discussing it with your healthcare provider can lead to early, personalized screening and potentially life-saving interventions. In Singapore, advances in genetic testing, multidisciplinary care, and national screening programmes offer effective tools to manage hereditary colorectal cancer risk. Taking proactive steps today can empower you to protect your health and that of your loved ones.
If you have concerns about colorectal cancer in your family, consult your doctor or a genetic counselor to determine the best screening and prevention strategies tailored for you.
Disclaimer: The content for this article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult your oncologist with any questions regarding a medical condition. Do not disregard medical advice or delay seeking it based on information from this site.