A new, 20-year population study of patients who received radiofrequency ablation for intrahepatic cholangiocarcinoma (iCCA) indicates that systemic therapy, local treatment and tumor size are associated with higher survival outcomes.
iCCA is a rare and aggressive disease, according to Qian Yu, MD, lead author of “Twenty-Years of Radiofrequency Ablation for Intrahepatic Cholangiocarcinoma: A Population Study.” Patients have limited treatment options, he said, and though surgical outcomes are decent, the rate of recurrence is very high compared to other tumors. Only a few patients are good surgical candidates.
However, the incidence of iCCA is rising, Dr. Yu said. “It is very aggressive and in the last 10 years there have been a lot of papers published in IR discussing ablation and radioembolization for treatment of this kind of tumor,” he said, adding that although there have been several landmark oncology papers discussing other treatment options in the last few years, generally IR isn’t considered the first line of treatment for this kind of tumor.
But because the field is rapidly evolving and these tumor types are rare, it’s difficult for a single institution to gather enough data to publish in a short amount of time in order to provide accurate data regarding treatment outcomes.
To review the efficacy and outcomes of various treatment models for iCCA patients, Dr. Yu and his team turned to the Surveillance, Epidemiology and End Results program, also known as the SEER database, which is the largest cancer database in the United States, run by the National Cancer Institute.
“We looked at 20 years of data for patients with iCCA and who received ablation. That only yielded about 190 patients,” Dr. Yu said. “We looked at the outcome, including survival, and we looked at the factors associated with survival.”
According to Dr. Yu, there is a noticeable difference in the survival outcomes for patients who were diagnosed after 2010. “This is likely due to the landmark systemic therapy trial—the ABC-02 trial. Basically, this trial set a standard of using gemcitabine plus cisplatin as a standard of care.”
Carcinoma is unique because unlike other tumors, a lot of oncologists believe this tumor is a combination of local disease plus distant metastatic spread, Dr. Yu said. “That's why even though some tumors are resectable, when you resect it, it comes back,” he said. “Sometimes you consider the tumor resectable when you cut the patient open, but then you find that patient already has a microscopic metastasis.”
The higher survival rate post-2010 reinforces the concept that systemic treatment plays an important role in the treatment of this aggressive disease, Dr. Yu said, especially for patients treated by IRs.
“When surgeons say something isn’t treatable with surgery, but know they can’t leave the patient without treatment, they send it to the IR,” he said. “So as IRs, we often deal with the aggressive subtype of this type of tumor.”
In addition to supporting the role of systemic treatment, the reviewed data also illuminated key factors associated with survival.
“We found that in terms of disease stage, like a local regional disease versus distant disease, patients with more local disease type show the better survival,” Dr. Yu said. “We also looked at tumor size. Using three centimeters as the cut off, those patients with smaller tumors had a better survival rate. This is likely, I believe, because for thermal ablation, smaller tumors will get better treatment coverage compared to larger ones.”
The researchers also compared tumors treated with ablation versus surgical resection. “If we just look at the tumors less than three centimeters and those diagnosed after 2010, we find a similar survival outcome between ablation versus surgical resection. And if we compare a patient who was treated by ablation to those treated by radiation therapy, we found that ablation actually gives better survival compared to those who are treated by radiation therapy,” Dr. Yu said.
These findings suggest that percutaneous thermal ablation might be underutilized compared to surgery, since the outcome is similar to surgery for small tumors. For non-resectable tumors, Dr. Yu said, perhaps percutaneous thermal ablation should be considered initially before sending patients to radiation therapy.
The restriction of a population database is that it doesn’t give researchers more detail compared to a single institutional study, Dr. Yu said, which is why his team is motivated to perhaps do a prospective study using a smoothing algorithm for ablation.
“Patients who experience recurrence after surgery or a recurrence after a local regional therapy tend to get more ablation because those tumors are very small,” Dr. Yu said. “Perhaps our next step is to adapt this treatment regimen toward the first line of treatment for smaller and non-resectable surgery candidates.”
And on the other hand, he said, researchers may use the collected data to investigate how socioeconomic status of patients might affect the outcome.
“Based on preliminary data, we found that patients who receive earlier treatment have better survival. Sometimes, patients with limited resources or insurance non-approval won't get treated on time. That may be associated with worse survival,” he said. “We also found that, based on household income, patients with an annual income greater than $75,000 tend to survive longer after ablation.”
This opens doors for researchers to see how socioeconomic status might affect treatment outcome and the ways that we can close the gap in terms of survival between patients from different socioeconomic backgrounds, he said.
“I feel like it's important for interventional radiologists from different institutions to collaborate with each other and share our understanding of the disease,” Dr. Yu said. “We need to work together on tackling iCCA, whether it’s a prospective registry study or prospective multicenter clinical trial, so patients will receive treatment and standard of care using the most updated systemic treatment of local plus regional treatment.”
