Only 5-10% of all cancers are truly hereditary, caused by gene mutations passed from parent to child that significantly raise lifetime cancer risk. BRCA1 and BRCA2 mutations increase breast cancer risk to 45-72% and ovarian cancer risk to 15-60% compared to 12% general population breast cancer risk. Lynch syndrome mutations raise colorectal cancer risk to 50-80%. Remaining 90% of cancers develop from acquired DNA damage over a lifetime not from inherited genes.

According to Dr. Sandeep Nayak, Best cancer treatment in Bangalore,
“Family panics when one person gets diagnosed and assumes everyone carries the gene. Most cancers aren’t inherited. But when they are the family needs testing not reassurance because what you don’t know can show up as Stage III in a relative who could’ve been screened from age 25.”

Most cancers aren’t inherited. But specific patterns in the family tree raise suspicion enough to warrant genetic counseling.

• Breast and ovarian: BRCA1 and BRCA2 are the most studied hereditary cancer mutations. Mother or sister with breast cancer before 50, ovarian cancer at any age, or male breast cancer in the family all point toward testing. Angelina Jolie put BRCA on the map but most Indian families still don’t know testing exists.
• Colorectal: Lynch syndrome mutations in MLH1, MSH2, MSH6, PMS2 cause up to 80% lifetime colon cancer risk. Family with multiple colon cancers across generations or colon cancer diagnosed under 45 needs genetic workup not just colonoscopy screening.
• Thyroid: Medullary thyroid cancer runs in families through RET gene mutations as part of MEN2 syndrome. One confirmed case in the family means every first-degree relative needs RET testing because prophylactic thyroidectomy in mutation carriers prevents a cancer that’s nearly certain to develop.
• Others: Li-Fraumeni syndrome from TP53 mutations causes childhood cancers and multiple adult cancers in the same person. APC mutations cause thousands of colon polyps starting in teenage years. CDH1 mutations raise stomach cancer risk high enough that preventive gastrectomy becomes a real conversation.

Your oncologist coordinates genetic counseling to determine which mutations your family pattern suggests testing for.

Genetic testing isn’t for everyone with a cancer diagnosis in the family. Specific patterns trigger the recommendation and random testing without those patterns wastes money and generates anxiety over results that don’t mean what people think they mean.

• Multiple relatives affected: Two or more first-degree relatives with the same cancer type or related cancers like breast and ovarian together. One uncle with prostate cancer at 75 doesn’t meet the threshold. Mother and grandmother both with breast cancer before 50 absolutely does.
• Young diagnosis: Cancer diagnosed before 45-50 in any family member raises hereditary suspicion. Early onset means something drove the cancer faster than random DNA damage usually does and that something is often an inherited mutation.
• Bilateral or multiple cancers: Same person getting cancer in both breasts, or developing colon cancer and then endometrial cancer. Multiple primary cancers in one individual strongly suggest a germline mutation driving the process not just bad luck repeating.
• Known mutation in family: One relative already tested positive for BRCA, Lynch, or RET. At that point every first-degree relative should get tested for that specific mutation. Blood test costs a few thousand rupees. Finding out you carry the mutation while you’re healthy gives you options that finding out after diagnosis doesn’t.

Understanding how refusing chemo affects outcomes helps put genetic testing in perspective because both decisions work better when based on data specific to your situation not general fear.

Dr. Sandeep Nayak’s team at MACS Clinic offers genetic counseling, testing coordination, and risk-reducing surgical planning for hereditary cancer carriers including BRCA-positive breast patients and RET-positive thyroid families all under one multidisciplinary team.

Positive mutation result here doesn’t end at a lab report. It starts a surveillance plan, a screening calendar, and if needed a conversation about preventive surgery with a surgeon who’s done these operations hundreds of times not occasionally.

References

1. Hereditary cancer syndromes — National Cancer Institute
2. Genetic testing for cancer risk — World Health Organization