RSNA 2003 

Abstract Archives of the RSNA, 2003


E09-0

Hot Topic: RF Tumor Ablation: Reduced Tumor Growth with Adjuvant External Beam Radiation in a Rat Breast Tumor Model

Scientific Papers

Presented on December 1, 2003
Presented as part of E09: Vascular Interventional (Dialysis Grafts and Catheters)

Participants

Clare Horkan MD, PRESENTER: Nothing to Disclose

Abstract: Abstract # 800040 aperr savage 2 11 2003-11-04T21:21:00Z 2003-11-14T15:54:00Z 2003-11-14T15:54:00Z 1 274 1564 Computer Services 13 3 1920 9.3821 6 pt 2 2   Purpose: To determine whether combined radiation therapy (XRT) and radiofrequency (RF) ablation increases endpoint survival over XRT or RF ablation alone in a animal tumor model. Materials and Methods: R3230 mammary adenocarcinoma (1.0 – 1.5 cm) was implanted subcutaneously in 36 female Fischer 344 rats. Tumors were randomized into four experimental groups: (a) conventional monopolar RF (70° C for 5 minutes) alone (n=8), (b) RF ablation followed by 20Gy external beam radiation (1Gray per minute) within 2 hours (n=10) (c) single dose 20Gy radiation alone (n=8), and (d) no treatment (n=10). The time when the tumor reached 3.0 cm in diameter (survival endpoint) was recorded. The effect of treatments on endpoint survival was analyzed by means of analysis of variance statistics. Results: Of the animals treated with combined FR and XRT, local control, manifest by complete resolution of the tumor, was achieved in 9 of 10 (90%) animals. This was significantly greater than the local control obtained in the RF alone group (1 of 8, 12.5%) (p<0.01). No local tumor control was seen in the control group of XRT alone group. Endpoint survival was greatest for the combined treatment group at 55 ± 17 days. Additionally, all three animals who died prior to 60 days succumbed to metastatic disease of the lung. Significantly lower survival was achieved for XRT alone (39.5 ± 14 days), RF alone (30.6 ± 15 days), and the control group (13.6 ± 6 days) (all p< 0.01 compared to combined therapy). Conclusions: The addition of single high dose radiation as an adjuvant to RF ablation dramatically improves outcomes. Local cure of subcutaneous mammary tumors can be achieved, and increased survival compared to either RF or XRT alone has been observed. Further parametric and optimization study of this paradigm is warranted in anticipation of potential introduction of this synergy into the clinic.

Cite This Abstract

Horkan MD, C, Hot Topic: RF Tumor Ablation: Reduced Tumor Growth with Adjuvant External Beam Radiation in a Rat Breast Tumor Model.  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3800040.html