Splenic Radioembolization in Patients with Extreme Splenomegaly

Sunday, March 30, 2025

3:54 PM – 4:03 PM CT

Location: Music City Center, 207 CD

Presenting Author(s)

Bela Kis, MD, PhD, FSIR (he/him/his)

Chief of Interventional Radiology
Moffitt Cancer Center, United States

Author/Co-author(s)

Ghassan El-Haddad, MD

Senior Member Interventional Radiology, Medical Director Radionuclide Therapy Program
Moffitt Cancer Center and Research Institute, United States
Altan Ahmed, MD

Assistant Member, Department of Diagnostic Imaging and Interventional Radiology
H. Lee Moffitt Cancer Center & Research Institute, United States
WG

Will Gibbons, MS

radiation physicist
Moffitt Cancer Center, United States
JM

Jonathon Mueller, MS

radiation physicist
Moffitt Cancer Center, United States
AK

Andrew Kuykendall, MD

oncologist
Moffitt Cancer Center, United States
TN

Taiga Nishihori, MD

Medical Director of Bone Marrow Transplant
Moffitt Cancer Center, United States

Purpose: Patients with extreme splenomegaly suffer from compressive symptoms and cytopenia with limited treatment options. Splenectomy in patients with extreme splenomegaly carries a mortality rate of up to 20%. Partial splenic bland embolization can be done but requires multiple embolizations to achieve sufficient splenic size reduction without major morbidity. This study evaluated the safety and efficacy of splenic radioembolization in patients with extreme splenomegaly.

Materials and Methods:

10 patients (7 male, 3 female, age 60.2±11.1 years) with extreme splenomegaly were treated with splenic radioembolization using Y90-labelled resin microspheres between June 2023 and September 2024. Extreme splenomegaly was defined as splenic size of at least 5x larger than the expected normal splenic size based on gender and height (1). The target treatment dose was 70 Gy to the treatment volume calculated with MIRD. All patients underwent pre- and post-treatment dosimetry using SPECT-CT. Dosimetry was performed using the Velocity software (Varian).

Results:

Technical success rate was 100%. Eight patients had complete, and 2 patients had partial splenic radioembolization with 61% and 67% of splenic volume treated. The delivered dose to the treated spleen volume was 64.6±16.3 Gy measured on the post-Y90 Bremsstrahlung SPECT-CT scan. The delivered microsphere density was 7.7±0.2 beads/mm³. The liver and lung shunts were 1.4±1.1% and 1.7±0.8%, and the liver and lung doses were 3.7±3.8 Gy and 5.1±1.9 Gy, respectively. The baseline splenic volume was 2580±1621 mL. The splenic volume reduction at 1, 3, 6 and 12 months was 37.3±11.8% (n=9), 59.2±10.3% (n=4), 72.1±0.8% (n=3) and 81.2±4.9% (n=2). There were no minor or major complications. Seven patients with myelodysplastic syndrome underwent successful allogenic stem cell transplant at a median of 14 days after splenic radioembolization.

Conclusion:

Radioembolization is a safe and effective treatment in patients with extreme splenomegaly with significant splenic size reduction within a few months without major morbidity or mortality. Further investigation is needed, but splenic radioembolization could become a practice changing procedure in the management of extreme splenomegaly that would otherwise require high risk splenectomy.