Simple blood test could help doctors decide cancer treatment

The test is based on cancer cells circulating in the blood flow and, as such, should be conducted before commencing treatment that reduces the scope of cancer cells.

  (photo credit: INGIMAGE)
(photo credit: INGIMAGE)

Diagnosing cancer today is very different than it was in the past, thanks to genomic tumor sequencing. Oncotest’s “Guardant360” liquid biopsy provides an accurate image of the condition using a simple blood test, enabling physicians to devise the best treatment within seven days.

Until the early years of this century, cancer was classified by the organ in which the tumor was detected (lungs, breast, colon, etc.) and other attributes such as tumor size, if it had infiltrated blood vessels and lymph nodes, and various other metrics. Patients suffering from cancer of the said organ and other similar attributes were treated with chemotherapy based on those metrics. However, two people with the “same” cancer may respond differently to the same treatment due to the different genomic profiles of each tumor.

Human genome sequencing presented a significant milestone in understanding diseases, including cancer. Upon identifying hundreds of genes relating to cancer proliferation, researchers realized a variance in the basic molecular structure of and within tumors. They understood that each tumor has a specific genomic profile.  Next Generation Sequencing (NGS) technologies enable physicians to concurrently identify all of the common genomic mutations of a specific tumor, which led to the development of cancer.

Personalized Medicine

“Treatment today is based on a personalized perspective, tailored to the tumor’s specific genetic profile,” explains Dr. Natalie Maimon, Lung Cancer Specialist and Head of the Lung Cancer Unit at the Meir Medical Center in Kfar Saba. “When patients are diagnosed with advanced cancer, it is important to provide them with the fastest and best treatment based on a genetic assessment and not solely based on chemotherapy, as was the case in the past.”

Targeted therapy may offer new and promising treatment options to patients with advanced-stage cancer, but without a clear DNA profile for the tumor, such treatments are inaccessible. Until recently, genetic tumor profiling was possible only through an invasive biopsy taken from the tumor tissue, a procedure that entails medical risks and discomfort.

Rapidly Completing the Puzzle

In recent years, a new method was developed for assessing the cancer tumor’s DNA profile – liquid biopsy. Malignant tumors secrete tiny quantities of circulating free DNA into the bloodstream, which contain the genetic transformations within the tumor itself. These tiny quantities are detected with Oncotest’s Guardant 360 liquid biopsy test, which helps physicians identify the correct therapeutic options for each patient. The test involves a simple blood test, in which circulating DNA is obtained from various cells, including the tumor cells. The test scans 74 genes related to cancer treatment, identifying DNA transformations derived from the cancerous tumor. Results are received within seven days after the blood test.

“In some cases, the information obtained after pathology analysis of the biopsy is limited and insufficient for a full molecular assessment,” explains Dr. Maimon. “Therefore, this test, which does not involve unnecessary pain or suffering, is a complementary piece that completes the puzzle of important therapeutic information. By sampling blood from two tubes, we actually obtain a genetic picture for dozens of genes.”

Studies have shown that this test is highly reliable, identifies mutations at 99.99% efficiency, and achieves an 85% correlation between the blood test gene sequencing results and their sequencing using tumor tissues taken in invasive biopsies.

Saves Unnecessary Treatments

According to Dr. Maimon, the test results are sent to the attending physician and often lead to a shift in the therapeutic approach, providing patients with rapid and correct treatment and saving on unnecessary treatments. “Even when a patient undergoes a certain biological treatment, and the patient ceases to respond, we often suggest a genomic evaluation by liquid biopsy in order to understand the cause for such resistance to treatment. This information is very important, and it helps us decide if the therapeutic approach should be changed or if we should introduce adjustments based on the findings.”

Dr. Maimon explains that the test is based on cancer cells circulating in the blood flow and, as such, should be conducted before commencing treatment that reduces the scope of cancer cells. “The test is indeed less sensitive than taking a biopsy from the tumor itself, but it is not always possible to do so. The liquid biopsy is an important complementary procedure because it provides a fuller picture of the heterogeneity of all of the metastases and not just of one tumor segment.”


This article was written in cooperation with Oncotest