ONE TIME BLOOD TEST FOR 8 TYPES OF CANCER: HUGE OPPORTUNITY TO INCREASE EFFICIENCY OF SCREENING, LOWER COST

The world's leading scientific journal SCIENCE on January 18, 2018 published an article introducing a blood test called CancerSEEK, which can detect 8 types of cancer. The article has attracted great attention from the scientific community. It opens up great opportunities, but also potential "pitfalls".
Developed by a team at Kimmel Johns Hopkins Cancer Center (Baltimore, Maryland, USA), CancerSEEK uses a "liquid biopsy" method to detect cancer. The authors tested eight proteins - often considered biomarkers of tumors - in blood and examined DNA fragments from 16 different genes, then used powerful computers to analyze the data. Whether. The number of volunteers participating in the trial was 1,005 patients with 8 types of cancer: ovarian, liver, stomach, pancreatic, esophageal, rectal, lung, breast cancer and 812 healthy people.
Liquid biopsy - detecting cancer from a blood sample, is a new approach in cancer diagnosis, mainly applied to advanced stage disease (stage IV). To date, most liquid biopsies have focused on detecting biomarkers of cancer or cell-free DNA (cfDNA), DNA caused by ruptured normal or malignant cells. released into the bloodstream (ctDNA).
Liquid biopsy will play an important role in cancer diagnosis in the future. Biomarkers circulating in the blood are more abundant and easier to detect, so liquid biopsy promises more diagnostic information than traditional methods of solid tumor biopsy
In addition, in patients with advanced cancer development, liquid biopsies can be used to characterize mutations in a type of cancer in cases where traditional methods are no longer suitable, and to help detect emerging mutations to predict the risk of resistance to cancer. treatment.
With that in mind, CancerSEEK opens up new opportunities, potentially becoming a good test for cancer screening in the future.
Advantages of CancerSEEK
With cancers of the ovary, liver, stomach, pancreas and esophagus, current tests have not yet yielded high screening results for the average-risk group. But CancerSEEK can do it. Enhancing diagnostic capabilities for a group of people with certain needs, as CancerSEEK is doing, is commendable.

CancerSEEK's limitations
CancerSEEK can only detect the disease in stages II, III, it can't detect early stage cancer, before there are clinical manifestations; while, the early diagnosis of cancer will bring significantly higher treatment efficiency.
This test is highly specific - 99% of blood samples from this group of cancer patients are positive. However, the correct diagnosis rate is only about 70%. Particularly for breast cancer, the correct detection rate is less than 40%. Thus, the sensitivity of this method is still low. That's because the proteins that the team chose to investigate are not specific to a type of tumor tissue. For example, serum protein CEA levels are commonly associated with colon cancer, but are also elevated in breast, lung, and prostate cancer patients.
In addition, inflammation and benign tumors can also cause serum protein levels to fluctuate (increase or decrease), similar to the situation that occurs in cancer patients. It is also important to note that some cancer-related mutations occur in "pre-cancerous" cases that do not require medical intervention. As such, those who receive negative results still cannot be completely reassured.
People who receive a positive result also need to be able to experience a false positive (diagnosed as cancer but not actually cancer). False positives can lead to unnecessary additional interventions, with undesirable consequences for the average person. The risk of harm to the patient - mentally, must also be considered.
Obviously, we can be optimistic about this experiment, but we need to make sure it doesn't hurt more people than it helps them. Testing cannot always be assumed to be beneficial.
In screening trials, specificity is particularly important - specificity for cancer and non-cancer; specific to each person's tissue type. Only after assessing all the risks, benefits, and costs of a new diagnostic technique can we be considered for its widespread use.
The good news is that Geisinger Health System (Danville, Pennsylvania) has partnered with Johns Hopkins University to continue the CancerSEEK trial for another 5 years on 50,000 female volunteers aged 65 to 75. The study was conducted in a population of individuals who have never been diagnosed with cancer, so the results should be very encouraging.
Dr. BS Nguyen Duy Sinh
Radiation Doctor, Oncology Department, Vinmec Central Park General Hospital