Lung metastases after liver resection or cryotherapy for hepatic metastasis from colorectal cancer--there is a difference!

Adenoviral-based immunotherapy provides local disease control in an orthotopic murine model of esophageal cancer

Despite recent advances in the development of novel therapies, esophageal carcinoma remains an aggressive cancer associated with a poor prognosis. The lack of a high throughput, reproducible syngeneic animal model that replicates human disease is partly responsible for the paucity of novel therapeutic approaches. In this report, we present the first successful syngeneic, orthotopic model for esophageal cancer. This model was used to test an established adenoviral-based tumor vaccine. We utilized a murine esophageal cancer cell line established from the ED-L2-cyclin D1;p53 mouse that was transduced to express a viral tumor antigen, the Human Papilloma Virus (HPV) E7 protein. The tumor was established in its natural microenvironment at the gastroesophageal junction. Tumor growth was consistent and reproducible. An adenoviral vaccine to E7 (Ad.E7) induced an E7-specific population of functionally active CD8 T cells that trafficked into the tumors and retained cytotoxicity. Ad.E7 vaccination reduced local tumor growth and prolonged overall survival. These findings suggest that orthotopic tumor growth is a reasonable preclinical model to validate novel therapies.

Clinical outcome, proteome kinetics and angiogenic factors in serum after thermoablation of colorectal liver metastases

Background

Thermoablation is used to treat patients with unresectable colorectal liver metastases (CRLM). We analyze clinical outcome, proteome kinetics and angiogenic markers in patients treated by cryosurgical ablation (CSA) or radiofrequency ablation (RFA).

Methods

205 patients underwent CSA (n = 20), RFA (n = 22), partial hepatectomy (PH, n = 134) or were found truly unresectable (n = 29). Clinical outcome, proteome transitions and angiogenic response in serum were analyzed at various time points after ablation.

Result

Median overall survival in CSA patients (17.6 months) was worse (p < 0.0001) when compared to RFA treated patients (51.7 months) and patients after PH (43.4 months). The complication rate was higher in the CSA group (50%) as compared to the RFA group (22%). Proteomics analyses showed consistently more changes in serum protein abundance with CSA compared to RFA. In the first four days after ablation a pro-angiogenic serum response occurred.

Conclusions

RFA of CRLM is superior to CSA with a median survival which equals survival in patients after PH. Proteomics analyses suggests a more aggravated serum response to CSA compared to RFA. Thermoablation is associated with changes in serum levels of angiogenic factors favouring a pro-angiogenic environment, but without differences between RFA and CSA.

Evidence for tumor cell spread during local hepatic ablation of colorectal liver metastases

INTRODUCTION

The aim of the present study was to analyze the impact of cryosurgery (CRYO) on liver metastases compared to other thermoablative techniques. In a rat liver metastases model, evidence for tumor cell spread was analyzed comparing CRYO, radiofrequency ablation (RFA), and laser-induced thermotherapy (LITT).

METHODS

In an experimental study, we compared cell spillage in the washout of isolated perfused rat livers undergoing thermal ablation. Within the same model, CC531-GFP rat liver tumors were treated with CRYO, RFA, or LITT and the number of vital tumor cells within the perfusate was measured. Matrix metalloproteinases (MMP-2, MMP-9) were analyzed after in vivo ablation of rat colorectal liver metastases in the third experimental model.

RESULTS

Our data showed pronounced washout of cells after CRYO with a higher amount of intravascular cells and cell detritus compared to RFA and LITT. Only the effluent fluid of cryosurgery-treated livers revealed GFP-stained tumor cells. MMP-2 and MMP-9 expression was significantly higher after cryosurgery than after RFA and LITT.

CONCLUSION

When using thermoablative techniques, intravascular metastatic cell spillage is highest in CRYO, and increased expression of matrix metalloproteinases may further facilitate tumor cell spread. Therefore, RFA and LITT may be preferable whenever surgical resection of liver tumors is impossible.

Patterns of recurrence after curative-intent radiation for oligometastases confined to one organ

OBJECTIVES

We sought to characterize and describe the patterns of distant recurrence in patients with macroscopic oligometastases, limited in number (<or=5) and confined to one organ, treated with curative-intent stereotactic body radiotherapy (SBRT).

METHODS

Seventy-seven patients enrolled on prospective studies of SBRT for oligometastases are included in the present analysis. All available radiography and records were retrospectively reviewed to determine the timing and location of recurrences.

RESULTS

New metastases occurred in 73% of patients. Among these patients, new metastases developed most frequently in the same organ (occurring in 82% of first new metastases after SBRT and 89% of cumulative new metastases). Metastases to other organs were common as well (occurring cumulatively in 79% of patients). In patients with liver oligometastases, common sites of further progression included the liver, other abdominal organs, and lungs. In patients with lung oligometastases, common sites of further progression included the lungs, thoracic lymph nodes, bones, liver, and brain.

CONCLUSIONS

Patients receiving SBRT for oligometastases confined to one organ are apt to develop new metastases, most frequently occurring in the initially involved organ, but also commonly in other organs. A subset of patients remains disease free after extended follow-up.

Cyclophosphamide unmasks an antimetastatic effect of local tumor cryoablation

Cryoablation of a solitary tumor mass releases intact tumor antigens and can induce protective antitumor immunity but has limited efficacy in the treatment of established metastatic cancer. Cyclophosphamide (Cy), an anticancer drug, selectively depletes regulatory T cells (T(reg)s) and attenuates suppression of antitumor immunity. We used a BALB/c mouse model of metastatic colon cancer to investigate the systemic antitumor effects of in situ cryotherapy alone or in combination with 200 mg/kg i.p. Cy. When combined with Cy, cryoablation was significantly more effective than either surgical excision or cautery at inducing systemic antitumor immunity, resulting in the cure of a fraction of animals with established metastatic disease and resistance to tumor rechallenge. Lymphocytes from cured animals contained an expanded population of tumor-specific, interferon-gamma producing T cells and transferred antitumor immunity to naive recipients. Depletion of CD8(+) cells significantly impaired the adoptive transfer of antitumor immunity. Furthermore, treatment with Cy and cryoablation was associated with a significant decrease in the ratio of regulatory to effector CD4(+) T cells. The combination of tumor cryoablation and Cy induces potent, systemic antitumor immunity in animals with established metastatic disease.