Using recent advances in radiotherapy (RT) planning and delivery, high-dose radiation delivered to hepatic tumors produced major survival benefits in patients with inoperable intrahepatic cholangiocarcinoma (IHCC), investigators reported online in Journal of Clinical Oncology.
“Treatment with ablative doses of RT using high-quality daily CT image guidance with inspiration breath-hold gating can achieve survival times comparable to those achieved with resection,” wrote Dr. Randa Tao, radiation oncologist at the University of Texas MD Anderson Cancer Center, Houston, and her colleagues (Jour Clin Onc. 2015 Oct 26 [doi: 10.1200/JCO.2015.61.3778]).
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From 2002 to 2014, 79 patients with inoperable IHCC were treated with definitive RT. The median survival time was 30 months; 1-, 2-, and 3-year overall survival rates were 87%, 61%, and 44%, respectively. Median progression-free survival was 30 months, and 1-, 2-, and 3-year progression-free survival rates were 88%, 61%, and 39%, respectively.
After completion of RT, 38 patients (48%) had primary tumor progression. Actuarial 1-, 2-, and 3-year local control rates were 81%, 45%, and 27%, respectively, with median duration of 23 months. The majority of patients (34) had recurrence within the high-dose radiation region, three had both in-field and marginal progression, and one had recurrence at the margin.
RT dose was the most important prognostic factor for overall survival and local control. Patients treated with doses higher than the conventional 50.4 Gy had a median survival of 43 months, compared with 23 months for patients treated with doses 50.4 Gy or less (P = .01).
Total biologically effective dose (BED) affected outcomes also. The 2- and 3-year overall survival rates for patients treated with BED greater than 80.5 Gy were both 73%, compared with 58% and 38% for those treated with BED of 80.5 Gy or less.
The treatment was well tolerated, with no cases of radiation induced liver disease observed.
The investigators recommend that higher total RT doses and higher doses delivered per fraction to achieve BED greater than 80.5 Gy should be considered for all patients as long as image guidance is used to ensure that the dose is delivered safely, and dose constraints to the liver, bile duct, stomach, and bowel can be met. The findings support the use of 67.5 Gy in 15 fractions (BED, 97.88 Gy).
Dr. Tao reported having no disclosures. Several of her coauthors reported having ties to industry sources.