Can CGP testing guide my husband's colon cancer treatment?

Question

Hello doctor,

My husband is 52 years old. He has recently been diagnosed with metastatic colon cancer, KRAS (Kirsten rat sarcoma viral oncogene homolog) wild-type. The oncologist mentioned possible genomic testing for treatment decisions. Please tell me,

What exactly does a comprehensive genomic profiling test test for in this setting?
How does it guide immunotherapy or targeted therapy choices beyond KRAS?
Should we be concerned about costs and whether insurance usually covers this type of testing?
Does this have any relevance for family genetic risk, or is it purely for tumor treatment guidance?

Kindly help.

Answer 1

Hello,

Welcome to icliniq.com.

I read your query and can understand your concern.

It is mandatory to go through the comprehensive genomic profiling (CGP) tests to analyze the tumor's DNA (deoxyribonucleic acid). It helps to understand a wide range of specific genetic mutations, biomarkers, and alterations beyond just KRAS (Kirsten rat sarcoma viral oncogene homolog). Key markers in metastatic colon cancer include:

MSI (microsatellite instability) status determines if the tumor is microsatellite instability-high (MSI-H).
The BRAF (B-Raf proto-oncogene) mutation shows more aggressive cancer.
HER2 (human epidermal growth factor receptor 2) amplification is helpful for therapies.
NTRK (neurotrophic tyrosine receptor kinase) fusions are rare but highly targetable alterations.

CGP is primarily for tumor treatment guidance. However, if the result shows MSI-H, it can sometimes be related to an inherited condition called Lynch syndrome.

Your oncologist will advise you if a separate genetic test (on a blood or saliva sample) is recommended for your husband to assess familial risk.

Based on this assessment, I can advise you on the following treatment options.

Immunotherapy: If the tumor is MSI-H (found in about 5 percent of metastatic colon cancers), immunotherapy (like Pembrolizumab) is often a highly effective first-line treatment.
Targeted Therapy: If a BRAF mutation is found, specific drug combinations can be used to target it.

This testing is considered the standard of care for metastatic cancer. Regarding your concern about insurance and cost, it usually covers it, but you must confirm this with the oncologist and your insurance provider beforehand to avoid unexpected costs.

I hope this information helps you.

Feel free to ask further queries.

Thank you.