SIR 2024
Interventional Oncology
Anna Bottiglieri, PhD
Postdoctoral scholar
Kansas State University
Financial relationships: Full list of relationships is listed on the CME information page.
Anna Bottiglieri, PhD
Postdoctoral scholar
Kansas State University
Financial relationships: Full list of relationships is listed on the CME information page.
Santosh Mandal, PhD
researcher
MD Anderson Cancer Center
Financial relationships: Full list of relationships is listed on the CME information page.
Santosh Mandal, PhD
researcher
MD Anderson Cancer Center
Financial relationships: Full list of relationships is listed on the CME information page.
Malea Williams, n/a
Research Investigator
Department of Interventional Radiology at The University of Texas MD Anderson Cancer Center
Disclosure information not submitted.
Malea Williams, n/a
Research Investigator
Department of Interventional Radiology at The University of Texas MD Anderson Cancer Center
Disclosure information not submitted.
Rahul A. Sheth, MD
Associate Professor
University of Texas MD Anderson Cancer Center
Financial relationships: Full list of relationships is listed on the CME information page.
Rahul A. Sheth, MD
Associate Professor
University of Texas MD Anderson Cancer Center
Financial relationships: Full list of relationships is listed on the CME information page.
A custom monopolar RF hyperthermia system, including a hypodermic needle (23-gauge, exposed tip = 4 mm) connected to a 500 kHz RF generator and a return electrode, was built to intratumorally deliver low (< 1W) or high ( > 1W) power for 15 minutes in a subcutaneous syngeneic rat models of HCC. Under US-guidance, a second needle was placed at a distance of 3.2 ± 1.3 mm from the central source needle. A thermocouple, welded to each needle, enabled real-time power control based on the temperature increase. Two heating protocols, designed to reach sub-ablative (T < 43 °C) and ablative temperatures (T > 50 °C) in the tissue between the two needles, were applied to each flank tumor (n = 4 per group). Intra-tumoral pressure was measured using a piezoelectric transducer attached to both needles. Shear wave elastography was used to evaluate the effect of the temperature on the tumor stiffness based on shear wave speed (SWS) measurements. Intratumoral pressure and SWS were measured before, and after hyperthermia, and at 24 h and 48 h post-procedure for treated as well as untreated tumors (n = 3).
Results:
Median values of the pressure in tumors treated to sub-ablative and ablative temperatures were 3.75 mmHg (IQR = 1.5 mmHg) and 3.0 mmHg (IQR = 2.0 mmHg) at 24 h post-treatment compared to the pre-treatment values, 10.5 mmHg (IQR = 2.0 mmHg) and 7 mmHg (IQR = 1.0 mmHg).The significant decrease (P < 0.05) in pressure values observed at 24 h was sustained at 48 h post-treatment in both treated groups. Median values of the untreated group were 7 mmHg (IQR = 0 mmHg), 10 mmHg (IQR = 2.25 mmHg) and 7 mmHg (IQR = 3.0 mmHg) at 0 h, 24 h and 48 h showing no significant change with time (P > 0.05). Sub-ablation treated tumors exhibited a significant decrease (P < 0.01) in the SWS immediately after RF heating. In the area around the source needle (radius ~ 3 mm), the median values decreased from initial 3.1 m/s (IQR = 0.7 m/s) to 1.6 m/s (IQR = 1.1 m/s). The rise to 2.1 m/s (IQR = 0.7 m/s) and 2.9 m/s (IQR = 0.8 m/s) at 24 h and 48 h post-intervention, suggests a transition time over which tumor stiffness tends toward the baseline. This effect was not observed in ablated tumors and untreated tumors.
Conclusion:
Hyperthermia to sub-ablative temperatures may modulate the tumor microenvironment by decreasing intratumoral pressure and stiffness. The temporary modulation of these biophysical characteristics of the tumor may improve the delivery of therapeutic agents and treatment response.