▲ Professor Changhoon Yoo is consulting a cholangiocarcinoma patient.

While the postoperative recurrence rate is high in extrahepatic cholangiocarcinoma (eCCA), no measure has been in place to predict the likelihood of recurrence in advance. CA19-9, though commonly used as a tumor marker, has issues of false negatives and positives, necessitating a more reliable biomarker. Professor Changhoon Yoo of the Division of Oncology at Asan Medical Center and his team recently published research findings showing that blood tests for circulating tumor DNA (ctDNA) analysis can predict the recurrence possibility of eCCA.

Circulating tumor DNA is basically cancer cell debris. As cancer cells grow, genetic fragments get altered to a specific form, that is ctDNA, and drift into the bloodstream. Professor Yoo’s team studied 89 patients who had undergone eCCA surgery and adjuvant chemotherapy between January 2017 and November 2020 and had their blood tested for ctDNA analysis. Then, the team analyzed the correlation between the presence of ctDNA and disease-free survival.

The analysis revealed that the hazard ratio of ctDNA positivity for disease-free survival was 3.81, meaning ctDNA-positive patients had an approximately four times higher recurrence rate. Changes in ctDNA status also affected survival rates. Patients whose ctDNA had been consistently confirmed negative had a 24-month survival rate of 80.4%. The survival rate was 50% for those whose ctDNA had been consistently confirmghltled positive. While patients whose ctDNA changed from positive to negative had a survival rate of 75%, the survival rate was 45.5% for those whose ctDNA changed from negative to positive. When 11 patients had their blood tested during adjuvant chemotherapy, their ctDNA turned from negative to positive, and eCCA recurred in all cases. Of these, it took an average of 222 days for three patients and 174 days for five patients whose ctDNA changed from negative to positive before recurrence.

Professor Yoo stated, “Before eCCA recurrence is confirmed via CT or MRI scans, a proactive treatment is expected to become available through a relatively simple blood test to detect ctDNA, identifying the possibility of recurrence early on.”

The research findings were recently published in the ‘Journal of Hepatology,’ one of the most prestigious academic journals in liver disease.