Colorectal cancer is one of the most common cancers worldwide. While lifestyle and environmental factors play a role, in some cases, the disease is linked to genetic changes passed down in families. This form is known as hereditary or genetic colorectal cancer.
Understanding how it is detected can help individuals at risk take timely steps for prevention, early diagnosis, and treatment. In this blog, Dr. Satish. C explains the importance of genetic testing, who should consider it, and the methods used for detection.
What is Genetic Colorectal Cancer?
Genetic colorectal cancer occurs when mutations in certain genes are inherited from one generation to the next. These mutations increase the risk of abnormal cell growth in the colon or rectum, leading to cancer.
The two most common inherited colorectal cancer syndromes are:
- Lynch Syndrome (Hereditary Nonpolyposis Colorectal Cancer or HNPCC): Caused by mutations in DNA mismatch repair genes. It significantly increases the risk of colorectal cancer, often at a younger age.
- Familial Adenomatous Polyposis (FAP): Characterised by hundreds of polyps in the colon and rectum, often starting in adolescence. Without treatment, the risk of developing cancer approaches 100%.
Who Should Be Tested?
Not everyone needs genetic testing. Dr. Satish C highlights some key red flags:
- Multiple family members diagnosed with colorectal cancer.
- A relative diagnosed at a young age (under 50).
- Cases of both colorectal and related cancers (like endometrial, ovarian, or gastric) in the family.
- A personal history of multiple polyps.
If you fall into these categories, your doctor may recommend genetic evaluation.
Methods of Detecting Genetic Colorectal Cancer
- Detailed Family History
The process begins with recording a thorough family history of cancers. Patterns across generations often give the first clue of a hereditary syndrome. - Genetic Counselling
Before testing, individuals meet a genetic counsellor to understand the benefits, risks, and implications of genetic testing for themselves and their families. - Genetic Testing
A simple blood or saliva sample can be analysed for mutations in specific genes linked to colorectal cancer. This is the most direct way to confirm hereditary risk. - Tumour Testing
For individuals already diagnosed with colorectal cancer, testing the tumour tissue for markers such as microsatellite instability (MSI) or mismatch repair (MMR) deficiency can indicate whether genetic testing is needed.
š½ Watch the video to learn more from Dr. Satish C about how genetic colorectal cancer is detected and what steps you can take if you or your loved ones may be at risk.
Why Early Detection Matters
Identifying genetic colorectal cancer risk has powerful benefits:
- Increased surveillance: Individuals at higher risk can undergo colonoscopies earlier and more frequently.
- Preventive options: Some may benefit from medications or surgeries that lower cancer risk.
- Family impact: Once a mutation is identified, relatives can be tested, allowing them to make proactive health decisions.
- Better treatment: Certain targeted therapies are more effective for cancers linked to specific genetic mutations.
The Bottom Line
Genetic colorectal cancer may sound daunting, but knowledge is power. With the right screening and early detection, it is possible to manage risks effectively and improve outcomes.
As Dr. Satish C emphasises, if you have a strong family history of colorectal cancer or related conditions, talk to your doctor about genetic counselling and testing.
