335 - Effect of Thermal Dosimetry, Energy Type and Concurrent Pharmacological Agent Administration on Infiltration of Lymphocytes into the Periablational Rim

Wednesday, April 15, 2026

11:15 AM - 11:24 AM ET

Author/Co-author(s)

MF

Mohamed Farghaly, MD

Postdoctoral research fellow
The Laboratory for Minimally Invasive Tumor Therapies, Department of Radiology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, Massachusetts, United States of America., United States
MC

Md. Raihan Chowdhury, PhD

Pots-doc Fellow
Beth Israel Deaconess Medical Center, United States
GS

Gokul Selveraj, MD

Post-doc Fellow
Beth Israel Deaconess Medical Center, United States
AA

Ahmed Abdelmonem, MD

Post Doc Fellow
Beth Israel Deaconess Medical Center, United States
Mohammed Elkholy, MD

Postdoctoral research fellow
The Laboratory for Minimally Invasive Tumor Therapies, Department of Radiology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, Massachusetts, United States of America, United States
AM

Ahmad Maaly, MD

Postdoctoral Research Fellow
Beth Israel Deaconess Medical Center/Harvard Medical School, United States
FW

Faris Weheba

Intern
Beth Israel Deaconess Medical Center, United States
GS

Geetika Surapaneni

Intern
Beth Israel Deaconess Medical Center, United States
AW

Allison Wu

intern
BIDMC, United States
VB

Vassiliki Boussiotis, MD

Hematologist/Oncologist
BIDMC, United States
SG

S. Nahum Goldberg, MD

Lecturer
Beth Israel Deaconess Medical Center, United States
MA

Muneeb Ahmed, MD, FSIR

Professor of Radiology
Beth Israel Deaconess Medical Center/Harvard, United States

Presenting Author(s)

Marwan H. Moussa, MD

Vascular and Interventional Radiologist
Beth Israel Deaconess Medical Center, United States

Purpose: Thermal ablation is a mainstay of oligometastatic locoregional control. Variable thermal dosimetry results in different periablational cell infiltration and distant off target effects. Similarly, concurrent systemic chemotherapy and anti-inflammatories affect periablational cells. Tumor infiltrating lymphocytes (TILs) play a major role in the development of anti-tumor immunity and are actively recruited by ablation. In this study, we investigate the
effects of variable thermal doses, energy types and concurrent administration of systemic agents on ablation-induced TILs in small animal models.

Materials and Methods: Phase IA; 12 rats were randomized into 4 groups for liver RFA (n=3): sham (probe insertion only), standard RFA (Std RFA, 70°C x 5 min), high RFA (Hi RFA, 90°C x 2 min), or low RFA (Lo RFA, 60°C x 10 min). Phase IB; 24 rats were randomized into 4 groups for liver MWA (n=6): low MWA (Lo MWA, 5 W x 120 sec), high MWA (Hi MWA, 20 W x 15 sec), standard RFA, or sham. Phase IC; 16 tumor-bearing rats were randomized into four groups for tumor RFA (n=4), receiving the same treatments as phase IA. In phase II, 12 rats were randomized into 4 groups for liver RFA (n=3): Std RFA alone, sham, Std RFA + cyclooxygenase-2 (COX-2) inhibitor, or Std RFA + liposomal doxorubicin. Animals were sacrificed 7 days post-treatment, ablated liver and tumor were harvested. CD4+ and CD8+ immunohistochemistry was done in the livers and CD4/CD8 ratio was calculated. Flow cytometry was done in the tumors: CD3, CD8, granzyme B, PD1, CD4, CD25, FoxP3.

Results: RFA dosimetry did not result in different lymphocyte infiltration patterns. Interestingly, Hi-MWA resulted in the lowest CD4+ and CD8+ infiltration when compared to Lo MWA and std RFA (p< 0.05). All RF and MW thermal doses produced significantly higher infiltration of CD4+ and CD8+ cells in the periablational rim compared to Sham group (p< 0.05). In RFA-ablated tumors, CD8+ intratumoral infiltration was lowest in sham, and increased with RFA (Sham vs Std/Hi; p< 0.05). CD8+/PD-1+ T cells increased in all RFA groups vs sham (p< 0.05), however, no difference between RFA groups. Hi RFA resulted in the highest infiltration of CD8+/GzB+ and CD4+/CD25+ T cells (Hi vs. Sham; p< 0.05). COX-2 inhibitor reduced CD4+ cells in the periablational rim vs Std RFA alone (p< 0.05).

Conclusion: Hi MWA settings may result in lower lymphocytes infiltration than Lo MWA. Hi RFA dosimetry may recruit less intratumoral activated CTLs and suppressor T cells. Finally, concurrent anti-inflammatories may inhibit CD4 periablational infiltration.