Foundational research by a City of Hope physician scientist and his colleagues could one day help metastatic colorectal cancer patients decide whether to choose immunotherapy or chemotherapy as their first treatment option. Immunotherapy is the new, hot thing, but sometimes traditional chemotherapy can be a better choice, said Marwan Fakih, M.D., senior author of the new study and co-director of the Gastrointestinal Cancer Program at City of Hope.
Our study suggests tumor genomics help doctors decide what kind of treatment will benefit each patient most. Taking this kind of personalize medicine approach; so they will be able to provide patients with options that yield better outcomes and are more cost-effective.
The degree of tumor mutation
The study, publish on April 30 in the journal Annals of Oncology, find that the degree of tumor mutation a patient with metastatic colorectal cancer had was associate with varying responses to immuno therapy when consider in combination with an establish bio marker called “microsatellite instability (MSI).
Comprehensive genomic profiling is critical to assess the underlying genomic drivers of a tumor; so as well as important biomarkers that require broad DNA interrogation like tumor mutational burden (TMB) and microsatellite instability (MSI), said Alexa Schrock, Ph.D., associate director of clinical development at Foundation Medicine. “In this study, we’ve seen the importance of evaluating both TMB and MSI when making treatment decisions for metastatic colorectal cancer patients.
At the moment, doctors rely only on MSI status to determine which metastatic colorectal cancer patients receive immunotherapy, Fakih said. He’s working to refine the markers that predict patient response to immunotherapy to improve the prognosis for colorectal cancer; so the third most commonly diagnose cancer in the world; so according to the World Health Organization. Although this type of cancer has on the decline, it is on the rise among young adults.
Personalize treatment for a patient
Finding methods to identify the right, personalize treatment for a patient is top-of-mind; so especially in today’s precision medicine landscape,” Fakih said. This study is the first to use degree of tumor mutation as a predictor of response to immunotherapy; hence in metastatic colorectal cancer patients with MSI. For cancer patients, timely, appropriate treatment is imperative.
Fakih and his colleagues retrospectively analyze the data of 22 patients all of whom had high MSI; so a biomarker that indicates they’re a good candidate to receive immune checkpoint inhibitor treatment. The scientists look at tumor characteristics, tumor genomics; also outcome data and compare those analyses to a database containing 18,140 metastatic colorectal cancer patients.
The implication is that patients with MSI and a high tumor mutation score should consider receiving immunotherapy as their first treatment, Fakih said. Those with MSI and a low tumor mutation score (less than 37) be consider for chemotherapy rather than immunotherapy as their first treatment option, Fakih added. Of course, more research is need to validate these important findings.