Radiation therapy in pancreatic cancer: current practice and future trends

Systematic review of innovative ablative therapies for the treatment of locally advanced pancreatic cancer

BACKGROUND

Locally advanced pancreatic cancer (LAPC) is associated with a very poor prognosis. Current palliative (radio)chemotherapy provides only a marginal survival benefit of 2-3 months. Several innovative local ablative therapies have been explored as new treatment options. This systematic review aims to provide an overview of the clinical outcomes of these ablative therapies.

METHODS

A systematic search in PubMed, Embase and the Cochrane Library was performed to identify clinical studies, published before 1 June 2014, involving ablative therapies in LAPC. Outcomes of interest were safety, survival, quality of life and pain.

RESULTS

After screening 1037 articles, 38 clinical studies involving 1164 patients with LAPC, treated with ablative therapies, were included. These studies concerned radiofrequency ablation (RFA) (7 studies), irreversible electroporation (IRE) (4), stereotactic body radiation therapy (SBRT) (16), high-intensity focused ultrasound (HIFU) (5), iodine-125 (2), iodine-125-cryosurgery (2), photodynamic therapy (1) and microwave ablation (1). All strategies appeared to be feasible and safe. Outcomes for postoperative, procedure-related morbidity and mortality were reported only for RFA (4-22 and 0-11 per cent respectively), IRE (9-15 and 0-4 per cent) and SBRT (0-25 and 0 per cent). Median survival of up to 25·6, 20·2, 24·0 and 12·6 months was reported for RFA, IRE, SBRT and HIFU respectively. Pain relief was demonstrated for RFA, IRE, SBRT and HIFU. Quality-of-life outcomes were reported only for SBRT, and showed promising results.

CONCLUSION

Ablative therapies in patients with LAPC appear to be feasible and safe.

Pilot trial of endoscopic ultrasound-guided interstitial chemoradiation of UICC-T4 pancreatic cancer

BACKGROUND AND AIMS

Both interstitial brachytherapy and interstitial chemotherapy are effective in improving local control in patients with local UICC-T4 pancreatic cancer. In this study, we report the results of endoscopic ultrasound (EUS)-guided interstitial chemoradiation (EUS-ICR) in patients with advanced pancreatic cancer, with respect to tumor response, clinical response, safety, and complications.

PATIENTS AND METHODS

A total of 8 patients (3 men, 5 women; median age of 69) with T4 pancreatic adenocarcinoma were the subjects of this study. A mean of 18 radioactive seeds and 36 intratumoral implants for sustained delivery of 5-fluorouracil in each patient were implanted into the tumors using EUS-guided needle puncture. The mean total implanted radioactive activity was 13.68 mCi, the mean total dose of intratumoral 5-fluorouracil was 3.6 g, and the mean volume of implants was 28 cm(3). The conditions of the patients were followed-up by examination and imaging tests every two months. Clinical endpoints included the Karnofsky performance status, pain response, tumor response (assessed by computed tomography and/or EUS), and survival.

RESULTS

During a median follow-up period of 8.3 months, the objective tumor response was classified as "partial" in 1 of 8 patients (with a median duration of partial response of 3 months), "minimal" in 2 patients, and indicative of "stable disease", in 3 of 8 patients. Clinical benefit was shown in 4 of 8 patients, which was mostly due to pain reduction, and lasted for 3.5 months. No local complications or hematologic toxicity occurred.

CONCLUSIONS

EUS-ICR had a moderate local anti-tumor effect, showed some clinical benefits in 4 of the 8 patients, and was well tolerated by all the patients in this study.

Diabetes mellitus in pancreatic cancer and the need for diagnosis of asymptomatic disease

Pancreatic cancer is strongly associated with the development of hyperglycemia, peripheral insulin resistance and diabetes mellitus, especially when presented as new-onset diabetes mellitus. Peripheral insulin resistance and hyperinsulinemia have been suggested to promote growth of pancreatic cancer cells, and therefore a relation between long-standing diabetes mellitus type 2 and pancreatic cancer has been implied. Epidemiological studies, though, give incongruent results to this problem. There are data supporting a tumor-derived influence on glucose metabolism, insulin secretion and eventually the development of diabetes mellitus in early stages of pancreatic cancer. The only possibility for curative intent in pancreatic cancer is to diagnose the disease before symptoms occur. Patients with newly diagnosed diabetes mellitus type 2 or hyperglycemia as a risk group have been recommended for primary screening for pancreatic cancer. To date, there is no specific biomarker to identify patients with an asymptomatic pancreatic cancer. The review discuss the relationship between pancreatic cancer and diabetes mellitus and the possibility of secondary screening of patients with newly diagnosed diabetes mellitus type 2 or hyperglycemia in an artificial neural network. PubMed was searched for articles using the Mesh term 'pancreatic neoplasms' combined with 'insulin resistance' and 'glucose metabolism disorders'. Additional articles were retrieved through hyperlinks and by manually searching reference lists in original published articles. In total 36 articles were systematically reviewed. and IAP.

Direct in vivo injection of 131I-GMS and its distribution and excretion in rabbit

AIM: To explore the distribution and metabolism of ¹³¹I-gelatin microspheres (¹³¹I-GMSs) in rabbits after direct injection into rabbits’ livers.

METHODS: Twenty-eight healthy New Zealand rabbits were divided into seven groups, with four rabbits per group. Each rabbit’s hepatic lobes were directly injected with 41.336 ± 5.106 MBq ¹³¹I-GMSs. Each day after ¹³¹I-GMSs administration, 4 rabbits were randomly selected, and 250 μL of serum was collected for γ count. Hepatic and thyroid functions were tested on days 1, 4, 8, 16, 24, 32, 48 and 64 after ¹³¹I-GMSs administration. Single-photon emission computed tomography (SPECT) was taken for each group on days 0, 1, 4, 8, 16, 24, 32, 48, 64 after ¹³¹I-GMSs administration. A group of rabbits were sacrificed respectively on days 1, 4, 16, 24, 32, 48, 64 after ¹³¹I-GMSs administration. Their livers were taken out for histological examination.

RESULTS: After ¹³¹I-GMSs administration, the nuclide was collected in the hepatic area with microspheres. The radiation could be detected on day 48 after ¹³¹I-GMSs administration, and radiography could be seen in thyroid areas in SPECT on days 4, 8, 16 and 24. One day after ¹³¹I-GMSs administration, the liver function was damaged but recovered 4 d later. Eight days after ¹³¹I-GMSs administration, the levels of free triiodothyronine and free thyroxin were reduced, which restored to normal levels on day 16. Histological examination showed that the microspheres were degraded to different degrees at 24, 32 and 48 d after ¹³¹I-GMSs administration. The surrounding parts of injection points were in fibrous sheathing. No microspheres were detected in histological examination on day 64 after ¹³¹I-GMSs administration.

CONCLUSION: Direct in vivo injection of ¹³¹I-GMSs is safe in rabbits. It may be a promising method for treatment of malignant tumors.

Dkk-3 expression in the tumor endothelium: a novel prognostic marker of pancreatic adenocarcinomas

Dkk-3 is proposed to be a new specific marker for tumor endothelial cells. Here we analyzed the clinical relevance of Dkk-3 expression in pancreas adenocarcinomas and determined its role on endothelial cell growth in vitro. Microvessel density in tumor samples was immunohistochemically determined using Dkk-3 and CD31 as endothelial cell markers, respectively. Based on the median microvessel density as a cut-off point, patients were categorized into high and low microvessel density groups and a correlation with survival and clinical parameters was assessed. Moreover, the role of Dkk-3 expression on chemosensitivity of endothelial cells was analyzed. In contrast to CD31 staining, Dkk-3-positive vessels were found only in tumor tissue and Dkk-3 microvessel density significantly correlated negative with tumor grading. In survival analysis the median survival time was 7 months for patients with Dkk-3 low, and 15 months for Dkk-3 high microvessel density (P = 0.0013). Subset analysis of patients receiving gemcitabine therapy showed that overall survival was significantly decreased in Dkk-3 low tumors than in high tumors (P = 0.009). In Cox regression Dkk-3 emerged as a significant independent parameter (P = 0.024). Dkk-3 overexpression in endothelial cells resulted in significantly enhanced growth inhibition after 5-fluorouracil or gemcitabine treatment compared to control endothelial cells and cancer cell lines. Dkk-3 low microvessel density was associated with tumor progression and worse clinical outcome. Overexpression of Dkk-3 enhanced endothelial cell growth inhibition to chemotherapeutic drugs. Therefore, we suggest that Dkk-3 high microvessel density may help to select patients who may benefit from chemotherapy.

Intraluminal implantation of radioactive stents for treatment of primary carcinomas of the peripancreatic-head region: a pilot study

BACKGROUND

Patients diagnosed with bile-duct, pancreatic-head, and ampullary carcinomas have a poor prognosis.

OBJECTIVE

This study evaluated the potential curative efficacy and safety of intraluminal brachytherapy by using radioactive stents for palliative treatment of these patients.

DESIGN AND SETTING

Patients with inoperable extrahepatic bile-duct (n = 2), pancreatic-head (n = 6), or ampullary (n = 3) carcinomas were treated by intraluminal implantation of radioactive stents designed according to a computerized treatment-planning system.

INTERVENTIONS

Both radioactive stents and commonly used self-expanding metallic or plastic stents were placed in the common bile duct (CBD) of the patients. For pancreatic carcinoma, the combination of radioactive CBD and pancreatic duct (PD) stents or only a radioactive PD stent was chosen according to the tumor position.

MAIN OUTCOME MEASUREMENTS

Survival, tumor status, and complications were assessed during the follow-up period.

RESULTS

A total of 16 radioactive stents were successively placed in all 11 patients. There were no life-threatening complications. The median survival was 150 days. After 2 months of the placement of radioactive stents, 8 patients (72.7%) had stable disease, whereas 3 patients (27.3%) showed progressive disease.

CONCLUSIONS

The combination of radioactive stents and metallic and/or plastic stents was technically feasible and tolerable in patients with advanced tumors around the pancreatic-head area.

A Novel Approach for Treatment of Unresectable Pancreatic Cancer: Design of Radioactive Stents and Trial Studies on Normal Pigs

PURPOSE

Patients diagnosed with pancreatic cancer typically have a poor prognosis. The aims of these studies were to design radioactive stents and to evaluate the feasibility and safety of the stents in animals.

EXPERIMENTAL DESIGN

To combine the effects of stents and brachytherapy, plastic stents with inserted iodine-125 seeds were designed and tested in 18 normal pigs. The pigs were divided into five groups on the basis of radiation dose. The estimated radiation dose at a 5-mm radial distance from the axis of the seeds was 50 Gy in group A, 100 Gy in group B, 150 Gy in group C, and 200 Gy in group D, with four pigs in each group. In the control group (n = 2), the same plastic stents with non-radioactive seeds were implanted in the pancreatic duct.

RESULTS

The procedures were successfully done on 14 of 18 (78%) pigs, whereas pancreatic duct perforation occurred in four pigs (22%). The thickened wall of the dilated pancreatic duct was clearly observed in the control group. However, the normal morphologic structure of the pancreatic duct wall disappeared in the experimental groups. Histopathologic examination revealed that the stents were surrounded with necrotic tissues and lateral fibrous tissues. During the follow-up period, the width of outside fibrous tissues gradually increased.

CONCLUSIONS

These results indicate that the radioactive stents are safe in all dose groups, and it is feasible to design a special radioactive stent for each patient according to the size, shape, and position of the pancreatic tumor.

The angiogenic switch molecule, secreted FGF-binding protein, an indicator of early stages of pancreatic and colorectal adenocarcinoma

Tumor angiogenesis has been related to the initiation as well as progression toward more aggressive behavior of human tumors. We will discuss genetic events underlying the initiation and progression of colorectal and pancreatic adenocarcinoma with a particular focus on the modulation of angiogenesis. A secreted fibroblast growth factor (FGF) binding protein (FGF-BP), which is an extracellular chaperone molecule for FGFs, has been shown to enhance FGF-mediated biochemical and biologic events and to be a crucial rate-limiting factor for tumor-dependent angiogenesis. Histochemical and in situ hybridization studies with archival samples show that FGF-BP is induced early during the initiation of colorectal and pancreatic adenocarcinoma. We will discuss the potential of this secreted protein as a serum marker to identify at-risk subjects.

Tumor angiogenesis: initiation and targeting - therapeutic targeting of an FGF-binding protein, an angiogenic switch molecule, and indicator of early stages of gastrointestinal adenocarcinomas -

Tumor angiogenesis has been related to the initiation as well as progression toward more aggressive behavior of human tumors. In particular, the activity of angiogenic factors is crucial for tumor progression. We previously characterized a secreted fibroblast growth factor-binding protein (FGF-BP) as a chaperone molecule, which binds to various FGFs, enhances FGF-mediated biochemical and biologic events and importantly is a crucial rate-limiting factor for tumor-dependent angiogenesis. We generated monoclonal antibodies that target FGF-BP protein and used them as a tool to evaluate frequency and pattern of FGF-BP expression during the malignant progression of pancreas and colorectal carcinoma in archival tissue samples. We found that FGF-BP is dramatically upregulated during the initiation of colorectal and pancreatic adenocarcinoma. Crucial genetic events underlying the initiation and progression of colorectal and pancreatic adenocarcinoma with a particular focus on the modulation of angiogenesis and antiangiogenic therapies are discussed. We propose that the upregulation of the secreted FGF-BP protein during early phases of pancreas and colon cancer could make this protein a possible serum marker indicating the presence of high-risk premalignant lesions. Furthermore, the biological activity of FGF-BP is neutralized by monoclonal antibodies suggesting the potential for antibody-based therapeutic targeting.

Apoptosis in human pancreatic cancer cells induced by eicosapentaenoic acid

OBJECTIVES

Clinical studies have shown that administration of eicosapentaenoic acid (EPA) to patients who have unresectable pancreatic cancer induces marked attenuation of cachexia. However, the exact mechanisms of the beneficial effect of EPA on pancreatic cancer are unknown. This examined the effect of EPA on proliferation of human pancreatic cancer cell lines and sought to clarify its mechanisms.

METHODS

The effects of EPA on proliferation of three human pancreatic cancer cell lines (SW1990, AsPC-1, and PANC-1) were assessed. Induction of apoptosis and expressions of apoptosis-related proteins were measured. The effect of EPA on cyclo-oxygenase-2 expression in these cell lines was determined.

RESULTS

EPA inhibited proliferation of all three human pancreatic cancer cell lines in a dose-dependent fashion. Simultaneously, EPA treatment induced apoptosis and this was associated with caspase-3 activation. EPA treatment was also associated with a decrease in intracellular levels of cyclo-oxygenase-2 protein.

CONCLUSION

We have demonstrated that EPA inhibits human pancreatic cancer cell growth due at least in part to the induction of apoptotic cell death. Such apoptosis is associated with activation of caspase-3 and suppression of cyclo-oxygenase-2 expression. Greater understanding of the molecular events associated with the biological activity of EPA should enhance the therapeutic potential of administration of EPA to patients who have pancreatic cancer.

EUS-guided interstitial brachytherapy of the pancreas: a feasibility study

BACKGROUND

Intraoperative interstitial brachytherapy has been effective when used at laparotomy to improve local control in locally advanced pancreatic cancer. Our aim in this study was to investigate the feasibility and the safety of EUS-guided brachytherapy of the pancreas in a porcine model.

METHODS

A modified 18-gauge needle with radioactive seeds was inserted, under EUS guidance, into the pancreas. The radioactive seeds were implanted into the tissue by the needle. After 14 days of clinical observation, the animals were euthanized, and the tissue response to brachytherapy was examined.

OBSERVATIONS

All the seeds were successfully implanted, and no migration occurred. Localized tissue necrosis and fibrosis was achieved in the pancreas, without significant complication. One pig had mild hyperlipasemia. Biochemical parameters were normal in the remaining pigs.

CONCLUSIONS

EUS-guided implantation of radioactive seeds is a safe, simple, and minimally invasive technique for interstitial brachytherapy.

Vascular endothelial growth factor-trap suppresses tumorigenicity of multiple pancreatic cancer cell lines

PURPOSE

Vascular endothelial growth factor A (VEGF-A) is a potent angiogenic agent that binds to two high affinity VEGF receptors (VEGFRs), a process facilitated by the low affinity neuropilin receptors. Although VEGF-A is overexpressed in pancreatic ductal adenocarcinoma, it is not known whether the in vivo growth of multiple pancreatic cancer cells can be efficiently blocked by VEGF-A sequestration.

EXPERIMENTAL DESIGN

Four human pancreatic cancer cell lines were grown s.c. in athymic nude mice. One cell line also was used to generate an orthotopic model of metastatic pancreatic cancer. The consequences of VEGF-A sequestration on tumor growth and metastasis were examined by injecting the mice with a soluble VEGFR chimer (VEGF-Trap) that binds VEGF-A with high affinity.

RESULTS

VEGF-Trap, initiated 2 days after tumor cell inoculation, suppressed the s.c. growth of four pancreatic cancer cell lines and markedly decreased tumor microvessel density. Analysis of RNA from tumors generated with T3M4 cells revealed that VEGF-Trap decreased the expression of VEGFR-1 and neuropilin-1 and -2. VEGF-Trap, initiated 3 weeks after tumor implantation, also attenuated intrapancreatic tumor growth and metastasis in an orthotopic model using PANC-1 cells.

CONCLUSIONS

VEGF-Trap is a potent suppressor of pancreatic tumor growth and metastasis and also may act to attenuate neuropilin-1 and -2 and VEGFR-1 expression. Therefore, VEGF-Trap may represent an exceedingly useful therapeutic modality for pancreatic ductal adenocarcinoma.

Adenovirus-mediated transfer of a truncated fibroblast growth factor (FGF) type I receptor blocks FGF-2 signaling in multiple pancreatic cancer cell lines

Pancreatic ductal adenocarcinomas (PDACs) overexpress several members of the fibroblast growth factor (FGF) family of ligands and the type I FGF receptor (FGFR-1), and enhanced FGF-2 protein levels correlate with shorter postoperative survival of patients with PDAC. In this study, we investigated the effects of FGF-2 on cell proliferation and mitogen-activated protein kinase (MAPK) activation before and after abrogation of FGFR-1-dependent signaling in 4 pancreatic cancer cell lines (ASPC-1, COLO-357, MIA-PaCa-2, and PANC-1). Signaling was blocked by infecting the cells with an adenoviral vector encoding for a truncated FGFR-1 (AdtrFGFR-1). FGF-2 enhanced the growth of all 4 cell lines and activated MAPK in 3 of these cell lines. Infection with the AdtrFGFR-1 virus resulted in abundant expression of the truncated FGFR-1 at the RNA and protein level, markedly attenuated FGF-2-induced proliferation in all 4 tested cell lines, and decreased FGF-2-dependent MAPK activation in the 3 cell lines in which FGF-2 activated this pathway. These findings suggest that FGFR-1-mediated mitogenesis in multiple pancreatic cancer cells can be efficiently blocked with an adenoviral vector encoding a truncated FGFR-1, raising the possibility that AdtrFGFR-1 may ultimately have a therapeutic role in PDAC.

Portal venous stent placement in patients with pancreatic and biliary neoplasms invading portal veins and causing portal hypertension: initial experience

PURPOSE

To evaluate the clinical usefulness of portal venous stent placement in patients with pancreatic or biliary neoplasms invading portal veins and causing portal hypertension.

MATERIALS AND METHODS

Thirteen patients underwent portal venous stent placement because of gastrointestinal bleeding (n = 8), risk of gastroesophageal varix rupture (n = 4), ascites (n = 4), thrombocytopenia (n = 3), and/or portal venous thrombosis (n = 3). The main portal vein or both the intrahepatic and main portal veins were invaded in six patients (group A). The main portal vein and splanchnic veins were involved in seven patients (group B). Stents were placed across the stenotic (n = 8) or occluded (n = 5) lesions after percutaneous transhepatic portography. Changes in portal venous pressure, stent patency, and survival were evaluated.

RESULTS

Mean portal venous pressure decreased significantly immediately after stent placement, from 24.9 mm Hg +/- 5.9 (SD) to 15.8 mm Hg +/- 4.6 (P <.001). In group A, blood flow through the stent was maintained and the symptoms had subsided at follow-up (mean, 12.5 months). In group B, symptoms were improved in five patients, but the stents were occluded in all but one patient at a mean follow-up of 1.5 months. There was a significant difference in stent patency between the patients with (14%) and those without (100%) splanchnic venous involvement (P <.01).

CONCLUSION

Stent placement helped to relieve portal hypertension symptoms. Splanchnic venous involvement was associated with worse stent patency.

Differentiation therapy of human cancer: basic science and clinical applications

Current cancer therapies are highly toxic and often nonspecific. A potentially less toxic approach to treating this prevalent disease employs agents that modify cancer cell differentiation, termed 'differentiation therapy.' This approach is based on the tacit assumption that many neoplastic cell types exhibit reversible defects in differentiation, which upon appropriate treatment, results in tumor reprogramming and a concomitant loss in proliferative capacity and induction of terminal differentiation or apoptosis (programmed cell death). Laboratory studies that focus on elucidating mechanisms of action are demonstrating the effectiveness of 'differentiation therapy,' which is now beginning to show translational promise in the clinical setting.