Cancer is more likely to be treated when it is detected as soon as possible, but it can be noticed and diagnosed and treated only after it has grown to a certain extent.

However, with the development of a technology that can detect trace amounts of cancer genes in the blood, a new treatment path has been opened.

This is Cho Dong-chan, a medical reporter.

<Reporter> Nam Yoo-

sun had breast cancer that recurred 7 years ago and spread throughout her body.

[Mammary gland/breast cancer patient: (breast cancer) relapsed and metastasized to the liver, lungs and bones.]

I changed the chemotherapy 7 times, but to no avail.

The patient and the attending physician had to face the final battle.

[Tae-Yoo Kim/Professor of Hematology and Oncology Department at Seoul National University Hospital: (to the patient) there is no more treatment, so what kind of (new) treatment does this patient's cancer cells have?]

[Nam mammary gland/breast cancer patient: ) Let's try a blood genetic test, so we're conducting a clinical test right now.]

He participated in a super-precision liquid biopsy clinical trial that detects 1 trillionth of a gram of cancer cells with 10cc of a patient's blood.

[Lee Ji-soo/Professor of Diagnostic Laboratory Medicine, Seoul National University Hospital: This is a test method that finds cancer cell gene (DNA) fragments present in the blood and detects and analyzes cancer gene mutations in that gene fragment.]

This is a CT image of the liver of this patient.

The cancerous masses that had spread to the liver have recently disappeared.

After identifying the cancer gene characteristics with a liquid biopsy, the appropriate anticancer drug was administered, which led to surprising results.

Seoul National University Hospital found a positive patient through a liquid biopsy when a colorectal cancer patient was not diagnosed with recurrence three weeks after surgery.

And after three years, positive patients had an actual recurrence rate eight times higher than negative patients.

If a positive person is found and an appropriate anticancer drug is administered in advance, the survival rate will be higher than it is now.

[Tae-Yoo Kim / Professor, Department of Hematology and Oncology, Seoul National University Hospital: Are the existing various cancer diagnostic tests indirect?

This liquid biopsy test analyzes the gene itself from cancer cells.]

Because of the advantage of detecting cancer at an extremely early stage, clinical trials for early detection of cancer in 100,000 people in the United States are also underway.

(Video coverage: Jeong Seong-hwa, video editing: Kim Jin-won, CG: Kim Hong-sik)