Neoadjuvant Yttrium-90 Transarterial Radioembolization with Resin Microspheres Prescribed Using the Medical Internal Radiation Dose Model for Intrahepatic Cholangiocarcinoma.

Purpose: To evaluate outcomes of patients with intrahepatic cholangiocarcinoma (iCCA) undergoing neoadjuvant yttrium-90 (Y) transarterial radioembolization (TARE) with resin microspheres prescribed using the Medical Internal Radiation Dose (MIRD) model.

Materials And Methods: This retrospective institutional review board-approved study included 37 patients with iCCA treated with Y-TARE from October 2015 to September 2020. The primary outcome was overall survival (OS) from Y-TARE. The secondary outcomes were progression-free survival (PFS), Response Evaluation Criteria In Solid Tumors 1.1 imaging response, and downstaging to resection. Patients with tumor proximity to the middle hepatic vein (<1 cm) and/or insufficient future liver remnant were treated with neoadjuvant intent (n = 21). Patients were censored at the time of surgery or at the last follow-up for the Kaplan-Meier survival analysis.

Results: For 31 patients (69 years; interquartile range, 64-74 years; 20 men [65%]) included in the study, the first-line therapy was Y-TARE for 23 (74%) patients. Imaging assessment at 6 months showed a disease control rate of 86%. The median PFS was 5.4 months (95% confidence interval [CI], 3-not reached). The PFS was higher after first-line Y-TARE (7.4 months [95% CI, 5.3-not reached]) than that after subsequent Y-TARE (2.7 months [95% CI, 2-not reached]) (P = .007). The median OS was 22 months (95% CI, 7.3-not reached). The 1- and 2-year OS rates were 60% (95% CI, 41%-86%) and 40% (95% CI, 19.5%-81%). In patients treated with neoadjuvant intent, 11 of 21 patients (52%) underwent resections. The resection margins were R0 and R1 in 8 (73%) and 3 (27%) of 11 patients, respectively. On histological review in 10 patients, necrosis of ≥90% tumor was achieved in 7 of 10 patients (70%).

Conclusions: First-line Y-TARE prescribed using the MIRD model as neoadjuvant therapy for iCCA results in good survival outcome and R0 resection for unresectable patients.