Chapter 5: How to Read and Understand Your Genomic Report
Chapter 5: How to Read and Understand Your Genomic Report
Making sense of the document that guides your personalized treatment plan.
When you receive your genomic test report, it may feel technical, long, and filled with unfamiliar terms. Many patients worry that they won’t understand what it means — and that’s completely normal.
This chapter will help you understand the key parts of a genomic report and how your oncologist uses it to guide your treatment. You don’t need to understand every detail. What matters is knowing what the report is trying to tell you.
Why Genomic Reports Look Complex
A genomic test analyzes thousands, sometimes millions, of pieces of DNA information. The report summarizes the most important findings, such as:
- Which gene changes were found
- Whether targeted therapies may work
- Whether immunotherapy markers are present
- Whether resistance mutations exist
- Whether you may qualify for clinical trials
Think of it as a health summary of your tumor, giving your doctor insight into what is driving the cancer and how best to treat it.
Key Sections of a Genomic Report (Explained Simply)
1. Summary of Findings
This is the “at-a-glance” overview. It highlights the most useful and actionable results — the “headlines” of your report.
2. Actionable Mutations (Targeted Therapy Opportunities)
This section lists the gene alterations that have approved medicines or clinical trials linked to them. If your report lists an actionable mutation, it means there is a specific weakness in the cancer that certain drugs can target.
What if No Actionable Mutations Are Found?
Sometimes, a genomic test does not identify a mutation that matches available targeted therapies. This may feel disappointing, but it is still valuable information.
Example: Colon Cancer and KRAS Wildtype
In colon cancer, doctors check the KRAS gene because it determines whether certain targeted therapies will work.
- If KRAS is mutated: Those drugs will not help.
- If KRAS is “wildtype” (no mutation found): It opens the door for targeted therapy options like EGFR inhibitors.
Why “No Mutation” Still Helps Your Doctor
- ✔ Avoids ineffective treatment
- ✔ Shifts focus to other strong options
- ✔ Helps consider immunotherapy markers
- ✔ Protects you from unnecessary side effects
- ✔ Identifies when deeper testing may be needed
Should You Consider More Comprehensive Genomic Profiling?
If no actionable mutation is found, ask your doctor whether your initial test was a limited panel, a hotspot panel, or a small panel looking at only a few genes. These tests are helpful but may miss important information.
You may benefit from additional testing:
Test TypeDescriptionWhat it includesComprehensive Panel100–1200+ genesMSI, TMB, Fusion genes, Copy number gains/lossesWhole Exome Sequencing~20,000 genesAlmost the entire coding region of your DNA
A simple analogy:
- Limited panels read a few chapters of the book.
- Comprehensive panels read most of the book.
- Whole exome sequencing reads the entire book.
3. Biomarkers for Immunotherapy
Your report often includes markers that help your doctor evaluate if immunotherapy could benefit you:
- MSI-H: Tumors with MSI-H tend to respond well to immunotherapy.
- TMB-High: A high number of mutations may increase sensitivity to immunotherapy.
- PD-L1 Expression: High PD-L1 levels may indicate better response to certain immune-based treatments.
4. Variants of Uncertain Significance (VUS)
A VUS simply means: “We found a change in a gene, but we don’t yet know what it means.” These findings do not affect treatment decisions today, though they may become relevant as science evolves.
5. Resistance Mutations
Some mutations indicate that certain treatments may not work or may stop working. This helps your doctor avoid ineffective options.
6. Gene-Level Details
This section contains technical information (gene names, mutation types, scientific references) used by your oncologist. You are not expected to interpret this section on your own.
7. Clinical Trial Opportunities
Based on your findings, the report may list trials for new targeted therapies or immunotherapies. This does not mean you must join a trial; it simply provides additional possibilities.
How Doctors Use Your Genomic Report
Your oncologist reviews all sections to determine:
- ✔ Whether targeted therapy or immunotherapy is an option
- ✔ Whether chemotherapy is still the best first line
- ✔ Whether a combination approach is needed
- ✔ Whether resistance mutations alter the plan
A Simple Analogy: Your Report is a Map
- Actionable mutations = roads leading to targeted drugs
- Immune biomarkers = signs pointing toward immunotherapy
- Resistance markers = roadblocks to avoid
- Clinical trials = alternative routes
A Final Note
Whether your report shows actionable mutations, immune biomarkers, or even “no significant findings,” each piece of information helps your doctor choose the right treatment for you.
The report does not make the decision — your oncologist does. And their goal is always to choose the safest, most effective, and most personalized treatment plan for your care.