The Importance of Genetic Testing in Metastatic Colorectal Cancer

Genetic testing is a laboratory method used to detect changes in genes, gene expression or chromosomes in a person's cells or tissues, according to the National Cancer Institute. Genetic testing may identify inherited gene changes that indicate an increased risk of developing a disease or condition or passing it to a family member, which is called germline testing. Genetic testing can also analyze tumor tissue for genetic changes in cancer cells that develop during a person’s lifetime and are not inherited, which is known as somatic testing and helps assess the cancer, guide treatment or monitor treatment response.

Recent advances in precision medicine have resulted in new treatments targeting genetic mutations. Notably, findings from the phase 3 CodeBreaK 300 trial have supported the use of a combination of Lumakras (sotorasib) and Vectibix (panitumumab) for patients with KRAS G12C-mutated metastatic colorectal cancer, as reported by Amgen, the manufacturer of the drugs.

On Jan. 16, the FDA approved a combination therapy for adults who previously received chemotherapy based on fluoropyrimidine, oxaliplatin and irinotecan, according to Amgen. This approval was based on findings from the CodeBreaK 300 trial.

CURE spoke with Dr. Marwan G. Fakih, lead investigator and professor of medical oncology at City of Hope in Duarte, California, about the importance of genetic testing, especially in a metastatic colorectal cancer setting.

Transcript:

So, in this day and age, every single patient with metastatic colorectal cancer should have upfront what we call next-generation sequencing of their treatment, meaning full profiling of the genetic alterations of their cancer. I think it's not acceptable not to know if a patient has a KRAS mutation, and it's not acceptable not to know what is that mutation. So that's part of the standard of care that has been the recommendation of the American Society of Clinical Oncology, to do KRAS testing, and the NCCN guidelines, that is standard guidelines across the world. I think what we have to learn as providers is to pay attention as to what is the mutation, because the main reason we used to test for KRAS is to know if a patient is candidate or not for Vectibix, which is panitumumab or Erbitux, which is cetuximab, those are targeted therapies, and in the presence of a KRAS mutation, those drugs should not be used.

Transcript has been edited for clarity and conciseness.

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