Patients with extrahepatic bile duct cancer face a high risk of recurrence even after five years and require continuous management, including regular screenings, according to a new study. While cancer patients are generally considered cured if they remain relapse-free for five years after treatment, the same standard is difficult to apply to extrahepatic bile duct cancer.
Samsung Medical Center announced Wednesday that a joint research team led by Professor Kim Hong-beom of the Department of Hepatobiliary-Pancreatic Surgery, Professors Shin Dong-wook and Choi Hye-rim of the Department of Family Medicine, and Professor Kang Dan-bee of the Clinical Epidemiology Research Center analyzed the conditional survival rate of extrahepatic bile duct cancer patients. The findings were published in the latest issue of HPB (Hepato-Pancreato-Biliary), the official journal of the International Hepato-Pancreato-Biliary Association (IHPBA).
Bile duct cancer is a malignant tumor that develops in the epithelium of the bile duct, the passage through which bile produced in the liver travels. It is divided into intrahepatic and extrahepatic bile duct cancer based on the anatomical location of the lesion. Extrahepatic bile duct cancer, in which tumors form in the bile passages outside the liver, is considered one of the most intractable cancers due to its high recurrence rate even after surgery.
For cancer patients, the five-year mark is generally a statistical benchmark used to assess treatment effectiveness and the likelihood of a cure. It is calculated by comparing the probability of a cancer patient surviving five years after diagnosis with the five-year expected survival rate of the general population. This standard is based on the fact that most cancer recurrences occur within five years. To more accurately evaluate the long-term prognosis of extrahepatic bile duct cancer patients, the research team examined the conditional survival rate. This method recalculates the probability of future survival after a patient has survived for a certain period, providing a more realistic prognosis than the conventional fixed survival rate.
According to the analysis, the five-year survival probability of extrahepatic bile duct cancer patients measured immediately after surgery was 41.3%, but the probability of surviving another five years for patients who had already survived five years after surgery was 51.9%, more than 10 percentage points higher. The probability of remaining recurrence-free also rose from 29.3% at the time of surgery to 50.0% five years after surgery. The survival probability for stage 3 patients, who have a poor prognosis, improved significantly from 14.6% initially to 53.3% after five years. This suggests that while extrahepatic bile duct cancer has a poor prognosis in the early stages of treatment, the likelihood of long-term survival can gradually increase once patients pass a certain period.
However, even when no signs of recurrence were observed for five years after surgery, the risk of recurrence remained at around 40%, and the decline in recurrence risk plateaued after six years. This means that even after long-term survival following diagnosis of extrahepatic bile duct cancer, the possibility of recurrence may not completely disappear. The research team attributed this to invisible micrometastases or the biological characteristics of the cancer.
"This study is the first to comprehensively analyze survival changes over time in extrahepatic bile duct cancer," Professor Choi said. "It provides a basis for patients to hold realistic hope during the course of their treatment."
"The risk of recurrence in extrahepatic bile duct cancer decreases over time but does not disappear entirely," Professor Kim stressed. "Regular screenings and long-term health management are essential even beyond five years."
