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Monday, December 14, 2020

Same-Day Holmium-166 Simulation and Treatment of Hepatic Metastases

Evaluation of the Safety and Feasibility of Same-Day Holmium-166-Radioembolization Simulation and Treatment of Hepatic Metastases 


Clinical question

Is same day Holmium-166 radioembolization simulation and treatment feasible and safe for the treatment of hepatic metastases?

Take away point
Same day Holmium-166 radioembolization simulation and treatment is safe and feasible for a select patient population.

Reference
van Roekel, C., N. I. Harlianto, A. J. A. T. Braat, J. F. Prince, A. F. van den Hoven, R. C. G. Bruijnen, M. G. E. H. Lam and M. L. J. Smits (2020). "Evaluation of the Safety and Feasibility of Same-Day Holmium-166 -Radioembolization Simulation and Treatment of Hepatic Metastases." Journal of Vascular and Interventional Radiology 31(10): 1593-1599.

Click here for abstract

Study design
Retrospective analysis

Funding Source
None

Setting
Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht University





Figure. Example case. A 65-year-old male with neuroendocrine tumor metastases was treated with same-day 166Ho-radio- embolization. Figure (a) shows the baseline contrast-enhanced CT image with a large hypervascular metastasis in segment 6. Figure (b) shows the distribution of 166Ho-scout on SPECT/CT. Figure (c) shows the distribution of the 166Ho-treatment dose on SPECT/CT. Figure (d) shows the contrast-enhanced CT image 3 months after treatment, with evident shrinkage (see annotation) of the metastasis in segment 6.

Summary


Holmium-166 (166Ho) microspheres are an alternative to yttrium-90 (90Y) for the treatment of liver metastases. 166Ho microspheres emit both beta and gamma radiation, allowing the same particle to be used for both simulation and treatment dosing which may simplify a same-day treatment procedure.

The authors reviewed 105 patients from previous prospective 166Ho radioembolization studies (HEPAR I and II, HEPAR PLuS, and SIM) who underwent same day radioembolization treatments. The patients underwent baseline triple phase abdominal CT, preliminary simulation angiogram and 166Ho scout administration, 166Ho-SPECT/CT to determine dose distribution and extrahepatic activity, and angiography with treatment dose delivery. The median scout procedure time was 1 hour and 43 minutes. The median treatment procedure time was 1 hour 11 minutes. The median total procedure time, including simulation, imaging, and treatment, was 6 hours and 39 minutes.

The technical success rate was 88%. The treatment plan was modified in 14 cases because of extrahepatic deposition, suboptimal targeting, and unanticipated vascular anatomy. Radioembolization was cancelled in 15 cases because of extrahepatic deposition, suboptimal targeting, unanticipated vascular anatomy, and dissection. Extrahepatic deposition was identified in 5 cases with no clinical significance. Side effects were comparable to the previously established side effects of radioembolization procedures and included back pain, chest pain, abdominal pain, contrast reaction, nausea, vomiting and dyspnea. While three patients experienced minor bleeding after sheath removal, the indwelling vascular sheath did not cause any adverse events.

Commentary


The authors reviewed 105 patients from previous prospective 166Ho radioembolization studies. The 88% technical success rate shows that single day radioembolization treatment is feasible. The lack of major adverse events suggests that the procedure is safe. As the authors described, the current study is limited by the heterogenous cohort, selection bias, and the learning curve related to the treatment technique. The author’s statement that they will not use a same day treatment approach at their institution because of 166Ho dosing limitations addresses a significant limitation to same day 166Ho treatment. Nevertheless, 166Ho radioembolization presents a compelling alternative to 90Y for treating liver metastases. 166Ho’s intrinsic properties that allow the same particle to be used for both planning and dose delivery presents a unique opportunity to improve the accuracy of dose administration. While single day 166Ho radioembolization is limited to a patient population in which a pretreatment dose estimation is viable, a single day radioembolization procedure remains an important subject as it presents an opportunity to decrease time to treatment and reduce medical cost.

Post Author
Maxwell Cretcher, D.O.
Integrated Interventional Radiology Resident, PGY-4
Department of Interventional Radiology
Dotter Interventional Institute, Oregon Health and Science University
@MCretcher

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