Adjuvant Radiotherapy Shows Survival Benefit for Patients Who Had Resection for Distal Cholangiocarcinoma

New findings suggest that some patients with cholangiocarcinoma, or bile duct cancer, could benefit from receiving radiotherapy after cancer treatment. Improved survival rates were associated with adjuvant radiotherapy for patients who underwent distal cholangiocarcinoma resection, regardless of nodal involvement or resection margin status, according to data published in Cancer.

“Because this is a disease with a very poor prognosis, we’re always looking for additional treatments that may help improve the results, over and above what we can achieve with surgery alone. Those options include chemotherapy and radiation, but there’s some uncertainty as to the role of radiation — whether it actually confers a survival benefit or not,” Dr. Hari Nathan, one of the study’s authors, said in an interview with CURE®. “(Although) we want to do anything that might be helpful, we don’t want to do things that don’t have evidence for increasing survival. So, we wanted to look again at the existing outcomes of patients on a national level to see what we could observe in terms of differences in survival for patients who received radiation therapy versus those who did not.” Nathan is an associate professor at Michigan Medicine.

Previously, distal cholangiocarcinoma had poor five-year survival rates, and chemotherapy has been the standard treatment. Adjuvant radiotherapy has been questionable because of the lack of conclusive evidence for a survival benefit, so researchers sought to analyze data for patients surviving more than six months after resection of distal cholangiocarcinoma.

Using the National Cancer Database, researchers identified 6,317 patients who underwent pancreatoduodenectomy, where the head of the pancreas, duodenum, a portion of the stomach and other nearby tissue is removed, for nonmetastatic distal cholangiocarcinoma; 2,162 received adjuvant radiotherapy, and 4,155 did not. In the study’s matched cohorts, for selection bias, 1,509 patients received adjuvant radiotherapy and 1,509 did not. Rates of node-negative disease, node-positive disease and unknown node status were 39%, 51% and 10%, respectively.

Adjuvant radiotherapy was associated with a significant survival advantage compared with lack of the treatment (median, 29 vs 27 months; five-year survival, 28% vs 25%), but the benefit was not seen in the unmatched cohort (28 vs 29 months; five-year survival, 28% vs 29%). In a multivariable analysis, older age, higher comorbidity score, advanced tumors, node-positive tumors and positive margin status were all associated with inferior survival outcomes.

Patients in the matched cohort with node-negative, node-positive or unknown node disease who received adjuvant radiotherapy all had survival benefits. Similarly, patients who received adjuvant radiotherapy had improved survival regardless of whether resection margins were clear or not.

“When delivered by experts, radiation therapy is generally very well tolerated,” Nathan said, adding that, like any medical treatment, it can cause side effects. “Patients should discuss (potential side effects) with their radiation oncologist, and, of course, every treatment decision to some degree should be individualized.”

The results suggest that adjuvant radiotherapy should be strongly considered for those who underwent distal cholangiocarcinoma resection, Nathan said. “It’s a retrospective study, and (it is possible) that, for example, healthier patients might have gotten radiation or patients with other favorable characteristics might have gotten radiation, skewing the results in their favor. We try to account for that using statistics, but you can’t ever account for that completely,” Nathan concluded.

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