Endobiliary radiofrequency ablation for malignant biliary obstruction due to perihilar cholangiocarcinoma (RACCOON): study protocol for a randomised controlled trial
The RACCOON trial is an international, multicentre, randomised controlled study designed to evaluate whether adding endobiliary radiofrequency ablation to standard uncovered self-expanding metal stents improves stent patency and reduces reintervention burdens for patients with inoperable perihilar cholangiocarcinoma.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Inside the body's intricate plumbing system, the bile ducts carry a vital fluid that helps digest food and remove waste. When a rare and aggressive cancer called perihilar cholangiocarcinoma grows in the area where these ducts meet, it acts like a stubborn clog, blocking the flow. This blockage causes severe jaundice, intense itching, and dangerous infections. For most patients, the cancer has spread too far or the patient is too frail for surgery to remove the tumor, so doctors must focus on keeping the ducts open to relieve suffering. The current standard approach involves placing a metal mesh tube, known as a stent, to hold the duct open. However, these tubes are not a permanent fix; the cancer often grows right through the mesh, causing the tube to clog again and forcing patients to undergo repeated, invasive procedures to clear the blockage.
Researchers are searching for a way to make these metal tubes last longer, potentially sparing patients from the cycle of obstruction and intervention. One promising method involves using heat to destroy the cancer cells growing inside the duct before the tube is placed. This technique, called endobiliary radiofrequency ablation, uses a specialized catheter to deliver controlled electrical energy that burns away the tissue. While this approach has shown promise in other contexts, it has not been rigorously tested as a standard addition to the metal stent for this specific type of cancer. The question remains whether adding this heat treatment to the standard metal tube actually extends the time the duct stays clear, or if it simply adds complexity without real benefit.
To answer this, a large international team of doctors launched a major clinical trial called RACCOON. This study is a randomized controlled trial, meaning patients with this specific cancer were assigned by chance to one of two groups. One group received the standard treatment: a metal stent placed to open the blocked duct. The other group received the same metal stent, but first, the doctors used the heat-ablation catheter to burn the cancer cells lining the duct. The goal was to see if this extra step of burning the tissue would prevent the cancer from growing back into the tube as quickly. The study involved hospitals across the Netherlands, Belgium, Romania, the Czech Republic, and the United States, enrolling over one hundred patients to ensure the results were reliable.
The researchers are carefully tracking how long the stents remain open before they clog again, a measure known as stent patency. They are also monitoring the patients' quality of life, the number of times they need to return to the hospital for additional procedures, and their overall survival. The study is designed to be open, meaning both the doctors and the patients know which treatment they are receiving, but the final judgment on whether a stent has failed is made by independent experts who do not know which group the patient was in. This helps ensure that the results are fair and based on clear medical evidence rather than expectation.
As of early 2026, the study has enrolled over one hundred patients and is on track to finish recruiting by mid-2026. Because the trial is still ongoing, there are no final results yet to declare a winner. The paper serves as the detailed blueprint for how this investigation is being conducted, outlining the strict rules for patient selection, the specific temperatures and timing used for the heat treatment, and the methods for analyzing the data. The researchers hypothesize that the group receiving the heat treatment will enjoy longer periods of relief without blockage, which would mean fewer hospital visits and a better quality of life for patients facing this difficult disease. Until the data is fully collected and analyzed, the medical community waits to see if this combination of heat and metal mesh can truly change the course of care for these patients.
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