Cancer recurrence as a result of drug resistance has been an ongoing battle. Far too many patients start treatment, experience great results, and then suddenly have their tumor reappear.
Quickly identifying when drug resistance may be occurring is critical to finding new treatments which will actually be effective for patients.
A New Study
This is what researchers from Harvard, MIT, IBM Research, and others have been working on improving. The results of their recent study have been published in Nature Medicine. These scholars conducted a study testing a new way of sampling tumors. This new method is called a liquid biopsy. This biopsy is able to test the patient’s DNA within the blood from the tumors (ctDNA). This ctDNA is isolated and then examined.
In this study, researchers compared liquid and standard biopsy samples from patients who had developed drug resistance. All 42 patients in this study had different kinds of gastrointestinal cancer and currently were having treatment with targeted therapy. As soon as drug resistance signs emerged, the biopsies were taken.
Standard tissue biopsies are common for diagnosing cancer. However, they are invasive and can only locate a single tumor. The problem is, tumor cells even in close proximity to another tumor can look different from the cells next door. Liquid biopsies allow researchers to examine the cells from many tumors which are in close proximity, showcasing more of the variation.
The researchers found that the liquid biopsies (as opposed to the standard biopsies) were able to tell them more about the patient’s genetic diversity and how drug resistance evolves at a molecular level. Understanding this evolution could be the key to understanding how to treat drug resistance patients. In 80% of patients, liquid biopsies identified more genetic alterations than the standard biopsies.
Unfortunately, the researchers also found many patients had multiple drug resistance mechanisms. The team explains that this may be exactly why drug resistance is so persistent and has been so hard to figure out.
Understanding these different molecular mechanisms may mean we can create more personalized therapeutics. The researchers explain that these biopsies should be used in clinics. Of course, larger clinical investigations are needed, especially in other cancers. But the use of machine learning in this study allowed researchers to find patterns of genetic differences and resistance mechanisms.
It’s a great step to understanding how to better treat many forms of cancer. You can read more about this study here.