Colorectal cancer (CRC) can be inherited in 10-15% of cases. Hereditary colorectal cancer awareness in India is still low despite rising cases. Many cases go undiagnosed due to lack of genetic testing, limited awareness and social stigma around discussing cancer.

Types of Hereditary CRC

1. Lynch Syndrome (HNPCC):

   – Accounts for ~3% of CRC cases, caused by mutations in DNA mismatch repair genes such as MLH1, MHS2, MSH6 and PMS2.

2. Familial Adenomatous Polyposis (FAP):

   – Resulting from the mutation of APC gene, causing hundreds to thousands of polyps in the colon, leading to near-certain CRC if untreated.

3. MUTYH – associated Polyposis (MAP):

  – Caused by mutations in MUTYH gene.

4. Peutz – Jeughers Syndrome: Associated with mutation in STK11 gene.
5. Cowden Syndrome: Caused by mutations in PTEN gene.
6. Juvenile Polyposis Syndrome: Associated with mutation in BMPR1A and SMAD4 gene.

Additionally, recent advancements in molecular techniques have identified new genes involved in CRC predisposition, including RPS20, POLE, POLD1, AXIN2, NTLH1, RNF43 AND GREM1.

Who is at Risk?

Individuals with a family history of CRC, especially if diagnosed before age 50.

Those with a personal or family history of polyps.

People with Lynch syndrome or FAP mutations.

Certain

Early Detection & Prevention

1. Screening:

   – Colonoscopies starting at age 40 (or earlier if family history is strong).

2. Genetic Testing:

   – Recommended for families with multiple CRC cases.

3. Lifestyle Changes:

   – A healthy diet, regular exercise, and avoiding smoking/alcohol can lower risk.

Awareness & Action

Educate families about genetic risks.

Encourage genetic counseling for high-risk individuals.

Promote early screening to prevent CRC development.