How to Read an NGS Cancer Report

Variants, biomarkers, evidence tiers and the questions to take to your oncologist

Key takeaways

• Confirm the patient, specimen and report version before interpreting a result.
• Read sample adequacy and limitations as carefully as the positive findings.
• The exact variant matters; two changes in the same gene may mean different things.
• An evidence tier is not the stage of cancer or a ranking of how ill someone is.
• Review uncertain findings and treatment associations with the treating team.

Begin with identity and the clinical question

An NGS report is easier to understand when you read it in a fixed order: identity, sample quality, findings, evidence and limitations. A listed alteration or medicine is not, by itself, a treatment recommendation.

Check the name and identifiers on your own report, the requesting clinician, sample site, collection date and issue date. If an amended report exists, use the latest authorised version and retain the earlier one for the medical record. These basic checks prevent an otherwise careful discussion from being based on the wrong specimen.

Next ask why the test was ordered. Was the aim to identify a treatment biomarker, investigate resistance, clarify a diagnosis or explore a trial? The same molecular finding can carry different significance in different cancer types. Oncquest's CGP sample reports show how specimen information, findings and interpretation fit together. Read the complete report rather than copying an example result to interpret your own test.^[1][2]

Report field	What to check
Specimen and date	The tissue site, collection date and whether this was before or after treatment.
Assay / quality	Panel version, genes and alteration classes, adequacy and any failed components.
Variant	Gene, precise DNA/protein notation and the relevant transcript.
VAF / depth	A measurement of supporting sequence reads, not a direct percentage of cancer.
Interpretation	Evidence tier, cancer-specific relevance and the stated limitations.

Read the adequacy statement first

Look for the tissue type, tumor-content assessment, coverage or read-depth information and any qualification about DNA or RNA quality. A laboratory may issue a result while noting that one component could not be assessed reliably. Do not assume that every item on the assay's menu produced a usable result in that specimen.^[1][2]

Coverage describes how thoroughly the relevant regions were examined; a summary average can hide uneven coverage at particular locations. Low tumor content or damaged material may reduce sensitivity. If a report says insufficient, indeterminate or failed, ask whether another block, a different method or another specimen would answer the question. That is different from accepting the result as negative.

Find the precise alteration

The gene name is only the beginning. Reports may include a transcript identifier, a coding DNA change beginning with c., a protein change beginning with p., an exon number or details of a fusion. Keep the complete notation when discussing a finding or seeking a second opinion.

For a small sequence variant, read depth and variant allele frequency provide measurement context. A fusion may instead have partner-gene names, breakpoint or supporting-read information. Copy-number results and genomic biomarkers use other reporting conventions. These fields should not be compared as if they were the same kind of score. The Oncquest examples illustrate several distinct reporting sections.^[1][2]

Understand evidence tiers and uncertain variants

The AMP, ASCO and CAP consensus framework separates variants with strong clinical significance (Tier I), potential clinical significance (Tier II), uncertain significance (Tier III), and benign or likely benign findings (Tier IV). Laboratories may use additional evidence labels within their reporting systems. Read the legend used on the actual report.^[3]

These categories describe clinical evidence, not cancer stage. A Tier I finding is not the same as stage I disease. A variant of uncertain significance, often shortened to VUS, is not proof that a medicine will work and should not generally determine treatment on its own. A finding's interpretation may change as evidence develops; ask how clinically important updates are handled.^[4]

Keep genomic biomarkers separate

A CGP report may contain MSI, TMB or other aggregate measurements as well as named gene alterations. Read each biomarker's own result, method, units, threshold and limitations. MSI status is not the same measurement as TMB, and neither automatically supplies a PD-L1 protein result.

Interpret a negative result carefully

No reportable alteration detected means something narrower than no cancer. The test may not cover the relevant gene, region or alteration class; the sample may contain too little tumor material; or the cancer may not have a finding with established significance. Some reports exclude findings that do not meet reporting criteria.^[4]

Ask whether the result is a valid negative within the tested scope or whether technical limitations leave an important question open. The next step could be no further molecular testing, a complementary assay or review of another specimen. Repeating the same panel without addressing the limitation may not add useful information.

Read treatment and trial appendices last

A treatment association may refer to evidence in the same cancer, another cancer, a particular line of treatment or an investigational setting. A trial entry may no longer be recruiting or may have eligibility criteria not visible in a short report summary. These sections are prompts for clinical review, not instructions to start a medicine.^[4]

Bring the complete report to your oncologist rather than a screenshot of one therapy table. Ask which findings could change care now, which might matter later and which are uncertain. Availability, local regulatory status, prior treatment, organ function and personal preferences also affect what is appropriate. The length of an appendix is not a measure of likely benefit.

Do not infer inherited risk from tumor findings alone

Tumor sequencing can detect a change that warrants a separate inherited-risk assessment. It cannot automatically establish whether that alteration is present in non-tumor cells. A VAF near 50%, for example, is not sufficient proof of an inherited variant; tumor composition and copy-number changes complicate interpretation.^[3]

The decision to pursue germline testing considers the gene and exact finding alongside personal and family history and relevant guidance. Appropriate confirmation and genetic counselling are needed before interpreting implications for relatives. Avoid arranging family testing solely from an isolated line in a tumor-only report.^[5]

Prepare for the results appointment

• Bring the complete report, including its methodology and limitations pages.
• Ask which result answers the original clinical question and how strong the evidence is.
• Identify any failed component or unresolved discrepancy that needs laboratory clarification.
• Ask whether complementary testing or genetic counselling is appropriate.
• Confirm whether a treatment or trial association is relevant and currently accessible.
• Agree who will document the interpretation and whether future reassessment is useful.

For an Oncquest report, use the website's Download Report route to access your results and keep all pages for the consultation. The published enquiry contacts are 0124 6650000 and life@oncquestlabs.com. Ask how to route a report-specific question to the issuing team, quoting the report reference. Then discuss the clarified finding and its treatment relevance with your oncologist.^[8]

Verified Oncquest offering facts

1

Diagnostic disciplines

Oncquest's diagnostic services include gene sequencing, molecular biology and surgical pathology.

Why it matters for you

Reading the molecular report beside the pathology findings keeps those different forms of evidence connected. For an Oncquest CGP result, retain the test name, code and complete authorised report so that any laboratory query refers to the correct analysis.

2

CGP 550+ catalogue scope

Oncquest's OncqSol CGP 550+ (OMO1034) includes TMB in its catalogue scope.

Why it matters for you

That does not make TMB, MSI and PD-L1 interchangeable results, or establish what a different CGP order includes. Match the report to the prescribed test code. If its score, category and narrative disagree, request clarification from the issuing laboratory before the disputed result is used in a clinical decision.

Frequently asked questions

FAQs

What does actionable mean on an NGS report?

It suggests that a finding may have relevance to diagnosis, prognosis, treatment or trial assessment. It does not mean that a particular therapy is appropriate or available for every person with that finding.

Does Tier I mean early-stage cancer?

No. Tier I describes evidence for a variant’s clinical significance. Cancer stage is determined separately using the appropriate clinical and pathological information.

Can a VUS guide treatment?

An uncertain variant should not generally determine treatment by itself. Ask whether any other established biomarker answers the treatment question and whether later reinterpretation is appropriate.

Is a high allele frequency a worse result?

Not necessarily. Allele frequency reflects the proportion of supporting reads and is affected by sample composition and biology. It is not a severity scale.

What if no mutation is found?

Review whether the analysis was adequate and what the assay covered. A negative panel does not rule out every relevant alteration or every treatment option.

What if two parts of the report conflict?

Ask the issuing laboratory for a written clarification or amended report. Do not select whichever statement seems more reassuring or use an unresolved interpretation for treatment.

Sources

1. Oncquest — CGP 270+ Sample Report Supplied SMO10765 example reviewed for structure and methodology only; individual findings are not reproduced.
2. Oncquest — CGP 550+ Sample Report Supplied OMO1034 example reviewed for structure and methodology only; individual findings are not reproduced.
3. AMP / ASCO / CAP — Somatic Variant Reporting Consensus Li et al., Journal of Molecular Diagnostics (2017); evidence tiers and interpretation principles.
4. National Cancer Institute — Biomarker Testing for Cancer Treatment General educational context on methods, interpretation and limitations.
5. National Cancer Institute — Genetic Testing Fact Sheet Inherited-risk testing, consent and genetic counselling.
6. Oncquest — OncqSol CGP 550+ Official catalogue: test code, specimen and listed biomarkers.
7. Oncquest — Company Overview Oncology focus, specialised diagnostic disciplines and laboratory network.
8. Oncquest — Patient Services and Enquiries Test search, centre search, online report access and published enquiry contacts.