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SIR 2026

Scientific Session

Session: Radioembolization 4

355 - Histopathologic Analysis of Intrahepatic Cholangiocarcinoma Treated with Transarterial Radioembolization Using Yttrium-90 Resin Microspheres

Wednesday, April 15, 2026
11:24 AM - 11:33 AM ET
Purpose: To evaluate the histopathologic effects of resin Yttrium-90 Transarterial Radioembolization (90Y-TARE) on intrahepatic cholangiocarcinoma (iCCA), and correlate dose with outcomes.

Materials and

Methods: This retrospective, single-center study included adult patients with iCCA treated with 90Y-TARE using resin microspheres. Histopathologic and dosimetry results were evaluated. Imaging response was assessed. Complete pathologic necrosis (CPN) was defined as 100% tumor necrosis, and extensive necrosis as >90% necrosis. Treatment factors affecting the pathologic necrosis rate were evaluated. Receiver operating characteristic curve (ROC) analysis was used to assess the ability of prescribed dose to predict extensive necrosis, with the optimal cut-point determined by the Youden index.

Results: For 18 patients, the median age was 69 years [IQR, 67-71 years], with 56% male, and median tumor size of 6.4 cm [IQR,5.1-8.2 cm]. Surgical resection was performed 127 [IQR, 100-182] days after 90Y-TARE. CPN was achieved in 4/18 (22%) patients, with extensive necrosis in 13/18 (72%) patients. ROC analysis demonstrated that the prescribed dose predicted extensive necrosis with an AUC of 0.84 (95% CI: 0.64–1.00). The optimal cutoff was 180 Gy, yielding a sensitivity of 77% and a specificity of 80%. Extensive necrosis rate was higher in patients with a prescribed dose > 180 Gy (10/11 [91%]), compared to patients with a prescribed dose < 180 Gy (3/7 [43%], p = 0.03). Patients treated with 90Y-TARE as a first line treatment had higher odds of achieving extensive necrosis compared to patients who received 90Y-TARE after chemotherapy (OR = 11, p = 0.047). All lesions classified as complete response by mRECIST at the 3-month evaluation exhibited extensive necrosis, corresponding to a sensitivity of 58% and a positive predictive value (PPV) of 100%.

Conclusion: 90Y-TARE with resin microspheres is associated with a CPN rate of 22% and extensive necrosis rate of 72% in iCCA, with a prescribed dose of >180 Gy predicting extensive necrosis.