Additive antitumour response to the rabbit VX2 hepatoma by combined radio frequency ablation and toll like receptor 9 stimulation

INTRODUCTION

Radiofrequency ablation (RFA), a palliative therapeutic option for solid hepatic tumours, stimulates localised and systemic antitumour cytotoxic T cells. We studied how far addition of CpG B oligonucleotides, toll like receptor (TLR) 9 agonists, would increase the antitumoural T cell response of RFA in the highly aggressive VX2 hepatoma.

METHODS

Rabbits were randomised to receive RFA, CpG B, their combination or no therapy. The antitumour efficacy of RFA alone or in combination with CpG B was further tested by rechallenging a separate group with intravenously injected VX2 tumour cells after 120 days. Animals were assessed for survival, tumour size and spread, and tumour and immune related histological markers after 120 days. Peripheral blood mononuclear cells were tested for tumour-specific T cell activation and cytotoxicity. Immune modulatory cytokines tumour necrosis factor α, interleukin (IL)-2/IL-8/IL-10/IL-12 and interferon γ, and vascular endothelial growth factor were measured in serum.

RESULTS

Mean survival of untreated animals was 36 days, as compared with 97, 78 and 114 days for RFA, CpG and combination therapy, respectively. Compared with untreated controls, antitumour T cell stimulation/cytotoxicity increased 26/16-fold, 32/17-fold and 50/38-fold 2 weeks after RFA, CpG and combination treatments, respectively. The combination inhibited tumour spread to lungs and peritoneum significantly and prohibited new tumour growth in animals receiving a secondary systemic tumour cell injection. RFA alone induced a Th1 cytokine pattern, while IL-8 and IL-10 were only upregulated in CpG treated animals and controls.

CONCLUSIONS

The combination of TLR9 stimulation with RFA resulted in a potentiated antitumour T cell response and cytotoxicity in the VX2 tumour model. Only this combination prevented subsequent tumour spread and resulted in a significantly improved survival, justifying the need for further exploration of the combination of ablative therapies and TLR9 agonists in liver cancer.

Contrast-enhanced ultrasound (CEUS) in hepatic lymphoma: retrospective evaluation in 38 cases

PURPOSE

Description of contrast-enhanced ultrasound (CEUS) patterns of hepatic lymphoma.

MATERIALS AND METHODS

Over a period of 6 years and 1 month from January 2006 to January 2012, n = 38 patients with histological or clinically apparent hepatic lymphoma were studied by means of CEUS prior to B-mode imaging.

RESULTS

Using B-mode imaging, lesions were hypoechoic in n = 37 (97.4 %) cases, while a focal lymphoma lesion was echo-rich in 1 case (2.6 %). For comparison, with CEUS, a hyperenhanced signal during the arterial phase was observed in n = 9 (23.7 %), an isoenhanced signal in n = 17 (44.7 %) and a hypoenhanced signal in n = 12 (31.6 %) cases. During the portal phase n = 2 (5.3 %) lesions were isoenhanced and n = 36 (94.7 %) were hypoenhanced followed by a hypoenhancement in n = 38 (100 %) cases in the late phase.

CONCLUSION

Lymphomas of the liver can cause different contrast accumulation in the arterial phase of CEUS. Furthermore, a clear differentiation from other malignant liver lesions such as metastases is crucial as different contrast accumulation in the arterial phase of CEUS is observed. In the late phase, hepatic lymphomas lead to a hypoenhancement in CEUS, also known as a "wash-out" phenomenon. In conclusion, CEUS is helpful to differentiate hepatic lesions by means of evaluating the malignancy or benignancy. In this regard, the application of CEUS can help to find the right diagnosis. A final discrimination between malignant liver lesions, such as liver lymphomas, metastasis or HCC, remains impossible.

Percutaneous ultrasound-guided radiofrequency ablation (RFA) using saline-perfused (wet) needle electrodes for the treatment of hepatocellular carcinoma--long term experience

PURPOSE

For many reasons, resection of hepatocellular cancer (HCC) is not feasible in most cases. Radiofrequency (RFA) ablation has proven to be an effective minimally invasive alternative. It has been shown in ex vivo and animal trials that needle applicators perfused with isotonic saline solution could be an effective approach to enlarging the coagulation zone. However, long term survival data for the treatment of HCC are not yet available.

MATERIALS AND METHODS

37 patients with a total of 64 histologically proven HCC with a maximum of 3 tumors of up to 6 cm and a contraindication to partial liver resection or orthotopic liver transplantation were treated with the Integra HiTT106 using wet monopolar single, wet bipolar double or wet triple needle electrodes. The mean HCC size was 37.7 mm (range 15 to 60 mm). Follow-up examinations were performed 2 days and 1, 3, 6, 9 months after RFA and every 6 months thereafter. The survival rate was calculated from the time of the first RFA session.

RESULTS

1, 2 and 5-year survival was 24/32 (75%), 14/31 (45%) and 3/21 (14%) overall; 18/19 (95%), 12/18 (67%) and 3/10 (30%) for HCC Child A; and 6/13 (46%), 2/13 (15%) and 0/11 (0%), for HCC Child B. Complete remission was achieved in 86.5 % of the patients (total: 32 out of 37, multi-needle 18 / 21, single needle 14 / 16). Distant recurrence occurred overall in 20 out of 37 patients (54%), including 9 of 21 treated with multiple needles (43% of patients) and 11 of the 16 patients treated with a single electrode (69%). The overall complication rate was 10.8%. Local recurrence was found for tumors measuring 3 cm-5 cm (n=28) in 7 out of 13 cases after single electrode RFA and in 1 out of 15 after multiple electrode treatment (significant, p=0.009). No significant difference between the single and multi-needle group was found for tumors >5 cm and <3 cm.

CONCLUSION

RFA using multiple wet electrodes shows promise as an effective method for treating inoperable HCC especially in cases with well-preserved liver function. Multiple electrodes seem to be superior to single electrodes with respect to the local recurrence rate for tumors between 3 and 5 cm.