The Anatomical Pattern of the Proximal Jejunal Vein as a Prognostic Factor in Patients With Pancreatic Head Cancer Treated With Preoperative Chemoradiation Therapy

BACKGROUND/AIM

The significance of the anatomical variations of proximal jejunal vein [the so-called 1st jejunal vein (J1v)] has been reported from a technical standpoint. The aim of this study was to retrospectively investigate the prognostic impact of the anatomical variations of J1v in the surgical treatment of resectable pancreatic cancer (PC).

PATIENTS AND METHODS

A total of 49 patients with resectable PC located in the uncinate process were included in this study. The J1v converging pattern was divided into 2 groups in terms of its relation to the SMA (i.e., the J1v status): i) group D: the J1v travels posterior to the SMA; ii) group V: the J1v travels anterior to the SMA. The associations between the J1v status and surgical outcome were assessed.

RESULTS

The 5-year survival rate after resection in group V (35%) was significantly lower than that in group D (70%) (p=0.029), and the J1v status of group V was the only independent negative prognostic factor (HR=5.49; 95% CI=1.69-19.3; p=0.005).

CONCLUSION

The J1v converging pattern is a significant prognostic variable in patients with PC located in the uncinate process: the J1v status of group V was significantly associated with impaired survival.

Peculiarities of ultrastructural organization and metabolism of reactive forms of oxygen and nitrogen in a cardiovascular system for permanent effects of ionizing radiation in low doses

OBJECTIVE

Determination of the peculiarities of ultrastructural changes and metabolism of reactive forms of oxy gen and nitrogen in the tissues of the myocardium, aorta and portal vein of the radiosensitive BALB/c mice due long term exposure to the complex of radionuclides of Chоrnobyl fallout (ejection) and low intensity low dose γ irradiation.

MATERIALS AND METHODS

Experimental studies were performed on 60 mice female radiosensitive lines BALB/c with a body weight of 20-22 g, which were divided into 3 groups: I group (control) animals age 6-9 months which were born and lived their lives in Kyiv vivarium under conditions natural radioactive background; ІІ - animals age 6 months, which were born and lived in the Chornobyl exclusion zone throughout their lives; ІІІ - animals, which from 3 months of age for 6 months were constantly located in cages with flat ionizing radiation sources and exposed to external γ irradiation in a total dose of 0.43 Sv. Animals of II and III groups were kept in the vivarium of the Institute for Safety Problems of Nuclear Power Plants of the National Academy of Sciences of Ukraine (Chornobyl). Mice of the BALB/c lines are sensitive to radiation: for males LD 50/30 < 5.7 Gy, for females - 5.85 Gy.

RESULTS AND CONCLUSIONS

The peculiarities of structural and functional changes in the organs of the cardiovascular system (CVS) and mechanisms of the development of oxidative and nitrosatitative stress due long term exposure to the complex of radionuclides of the Chornobyl fallout (ejection) and low intensity low dose γ radiation based on the study of ultrastructural organization and metabolism of reactive oxygen species (ROS) and nitrogen (NRS) of the atri al cardiomyocytes (CMC), the aortic endothelium and portal vein of the BALB/c mice. Found that the permanent expo sure to low doses of radiation changes occur, including the dominant mechanism is to run a CMC apoptosis and endothelial cells of the aorta and portal vein. It is shown that the development of oxidative stress accompanied by increased activity of ROS metabolism that occurs due to activation of nucleotide and lipid superoxide generators. Found that under these conditions the development of nitrosative stress is due to the activation of inducible NO syn thesis enzyme iNOS and inhibit its synthesis constitutive eNOS enzyme. High levels of simultaneous generation of superoxide and NO, bindting, lead to the formation of toxic peroxynitrite, which initiates the process of apoptosis.

[Features of contrast enhancement in different methods of multislice computed tomography]

The purpose of this study was a comparison of the X-ray density in certain organs and anatomical structures and the determination of the radiation exposure during venous-arterial MSCT scanning and classical two-phase CT of organs of the abdominal cavity. It has been established that the technique of venous-arterial MSCT scanning provided a significant reduction of radiation dose during CT of organs of the abdominal cavity and could be used as an alternative to two-phase examination in the process of dynamic monitoring of cancer patients.

The role of radiotherapy in the treatment of hepatocellular carcinoma with portal vein tumor thrombus

The aim of this study was to evaluate the role of radiotherapy in the treatment of hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVT) and to determine the prognostic factors for overall survival. Altogether, 106 patients with HCC and PVT referred for radiotherapy between 2004 and 2009 were retrospectively reviewed. A total of 60 Gy in 30 daily fractions was delivered with intensity-modulated radiotherapy techniques. Patient-related and treatment-related factors were analyzed to evaluate their prognostic significance for the overall survival rate. Complete response was noted in 10 patients and partial response in 55 patients. The liver lesions had become resectable after the completion of radiotherapy in 12 patients, and surgery was subsequently performed. One or two courses of transarterial chemoembolization (TACE) were administered to 19 patients following radiotherapy. The 1-year and 2-year overall survival rates were 34.7% and 11%, respectively, and the median survival was 7 months for the entire cohort of patients. Post-radiotherapy treatment modality, response to radiotherapy and JIS score were demonstrated as independent prognostic factors for overall survival (P = 0.003, P < 0.001, P < 0.001, respectively). For patients who received surgical intervention after radiotherapy, the median survival was 30 months and the 2-year overall survival rate was 67%. Radiotherapy achieved a 61.5% objective response rate and prolonged survival in patients with PVT. The liver tumors had become resectable after radiotherapy in 11% of patients. Our results suggested that radiotherapy could offer survival benefits and should be considered as a treatment option for patients with PVT. Radiotherapy could also be considered as a preoperative treatment modality in patients with HCC and PVT.

Prediction of liver function by using magnetic resonance-based portal venous perfusion imaging

PURPOSE

To evaluate whether liver function can be assessed globally and spatially by using volumetric dynamic contrast-enhanced magnetic resonance imaging MRI (DCE-MRI) to potentially aid in adaptive treatment planning.

METHODS AND MATERIALS

Seventeen patients with intrahepatic cancer undergoing focal radiation therapy (RT) were enrolled in institution review board-approved prospective studies to obtain DCE-MRI (to measure regional perfusion) and indocyanine green (ICG) clearance rates (to measure overall liver function) prior to, during, and at 1 and 2 months after treatment. The volumetric distribution of portal venous perfusion in the whole liver was estimated for each scan. We assessed the correlation between mean portal venous perfusion in the nontumor volume of the liver and overall liver function measured by ICG before, during, and after RT. The dose response for regional portal venous perfusion to RT was determined using a linear mixed effects model.

RESULTS

There was a significant correlation between the ICG clearance rate and mean portal venous perfusion in the functioning liver parenchyma, suggesting that portal venous perfusion could be used as a surrogate for function. Reduction in regional venous perfusion 1 month after RT was predicted by the locally accumulated biologically corrected dose at the end of RT (P<.0007). Regional portal venous perfusion measured during RT was a significant predictor for regional venous perfusion assessed 1 month after RT (P<.00001). Global hypovenous perfusion pre-RT was observed in 4 patients (3 patients with hepatocellular carcinoma and cirrhosis), 3 of whom had recovered from hypoperfusion, except in the highest dose regions, post-RT. In addition, 3 patients who had normal perfusion pre-RT had marked hypervenous perfusion or reperfusion in low-dose regions post-RT.

CONCLUSIONS

This study suggests that MR-based volumetric hepatic perfusion imaging may be a biomarker for spatial distribution of liver function, which could aid in individualizing therapy, particularly for patients at risk for liver injury after RT.

Efficacy of radiotherapy for PV and IVC tumor thrombosis in unresectable HCC

BACKGROUND/AIMS

The purpose of this study is to evaluate the effect of radiation therapy (RT) for tumor thrombosis (TT) in the major portal vein (PV) or inferior vena cava (IVC) from unresectable hepatocellular carcinoma.

METHODOLOGY

Fifteen HCC patients with main PVTT (n = 10) and IVCTT (n 5) were treated with three-dimensional conformal RT between 2001 and 2004. The mean dose was 38.5 Gy (range 28 to 54Gy). The concurrent therapies to intrahepatic tumor included transcatheter arterial chemoembolization (TACE) in 7, TACE + hepatic arterial infusion in 2 and systemic chemotherapy in 1 patient. The therapeutic effect was assessed by tumor regression for TT.

RESULTS

An objective response was observed in 3 of 15 patients (20%). There were no patients with progressive disease. The median survival time was 10 months. In 12 cases with stable disease, time to progression (TTP) estimated above 6 months were 42% (5/12 cases). In univariate analysis, therapeutic effect and TTP were affected to survival time. All patients did not have severe deterioration of liver function.

CONCLUSIONS

In the current study, we concluded that RT was superior treatment in terms of local control capability and was useful to continue further treatment because RT did not make liver function worse.

Radiofrequency ablation of the pancreas. I: Definition of optimal thermal kinetic parameters and the effect of simulated portal venous circulation in an ex-vivo porcine model

CONTEXT

Radiofrequency ablation of pancreatic tumours carries a risk of injury to important structures such as the bile duct and duodenum. We have recently developed an ex-vivo model of radiofrequency ablation of the porcine pancreas.

OBJECTIVE

This study evaluates the effect of variations in probe temperature, duration of ablation and simulated portal venous flow on radiofrequency-induced injury. SPECIMEN RETRIEVAL: Pancreata of 30 6-month-old healthy pigs undergoing sacrifice in a commercial abattoir were used.

INTERVENTIONS

Radiofrequency energy was applied to a pre-marked area of the pancreatic head. Pancreatic head biopsies were taken after ablation to incorporate duodenum, portal vein and bile duct respectively and frozen in liquid nitrogen. For each experiment a portion of the tail of the pancreas was studied as non-ablated control. Paired slides using haematoxylin and eosin (H&E) and nicotinamide adenine dinucleotide (NADH) stains were prepared.

MAIN OUTCOME MEASURES

The effects of variation in target temperature (100 degrees C to 80 degrees C), duration of ablation and of simulated portal perfusion were studied.

RESULTS

Optimal thermal kinetic characteristics were produced by a target temperature of 90 degrees C applied for 5 minutes. At this temperature there was ablation of pancreas without injury to adjacent viscera. Higher temperatures resulted in injury to the bile duct and portal vein. Simulated portal circulation had no effect on ablation.

CONCLUSIONS

In this ex-vivo study radiofrequency produced a temperature and duration dependent ablation with the optimal characteristics being 90 degrees C for 5 minutes.

Intraoperative Radiation Therapy in Liver Tissue in a Pig Model: Monitoring with Dual-Modality PET/CT

PURPOSE

To assess, in a pig model, the value of dual-modality positron emission tomography (PET)/computed tomography (CT) for monitoring radiation therapy.

MATERIALS AND METHODS

Central bile duct resection followed by creation of a biliodigestive anastomosis was performed in nine pigs. Six of these pigs were also treated with intraoperative radiation therapy (IORT) (20 Gy) in the area of the anastomosis. Two, 4, and 8 weeks postoperatively, contrast material-enhanced fluorine 18 fluorodeoxyglucose (FDG) PET/CT of the liver was performed in all of the animals. The radioactive tracer concentration in the region of the anastomosis was quantified, and the values were compared intraindividually with the values at the liver periphery. Histologic evaluation of the liver was performed 8 weeks postoperatively. The PET/CT images were assessed for changes in liver volume and bile duct diameter over time.

RESULTS

In all nine pigs, the region of the anastomosis could be clearly defined on the fused PET/CT images. PET/CT revealed a decreased concentration of FDG in the irradiated field 2 and 4 weeks after IORT. At 8 weeks, however, the distribution of the tracer in the irradiated pigs did not differ from that in the nonirradiated pigs. Homogeneous tracer uptake in all liver regions was observed in the nonirradiated animals. The CT images showed an increase in liver volume in all pigs and bile duct dilatation that increased over time in the irradiated pigs.

CONCLUSION

The morphologic and functional changes due to IORT in liver tissue can be accurately monitored with dual-modality PET/CT. By enabling the integration of functional and morphologic data, PET/CT may have an important role in monitoring radiation treatment.

Theoretical analysis of the heat convection coefficient in large vessels and the significance for thermal ablative therapies

Ablative therapies such as radio-frequency (RF) ablation are increasingly used for treatment of tumours in liver and other organs. Often large vessels limit the extent of the thermal lesion, and cancer cells close to the vessel survive resulting in local tumour recurrence. Accurate estimates of the heat convection coefficient h for large vessels will help improve ablation techniques, and are required for estimation of thermal lesion dimensions in simulations. Previous estimates of h did not consider that only part of the vessel is heated, and assumed uniform temperature distribution at the vessel wall. An analytical relationship between the heat convection coefficient, blood velocity and temperature is formulated. The heat convection coefficient evaluated will assist both simulations and design of proper protocols for in vivo measurements. The mathematical model developed in this work describes the exchange of heat between a solid surface and a moving fluid and it is based on energy and motion equations for Navier-Stokes fluids. A particular case of a laminar blood flow in the portal vein is studied when a portion of its surface is heated. The results show that heating a larger portion of the vessels reduces convective heat loss, which may result in more effective ablation strategies.

[Effect of He-Ne laser irradiation on the functional activity of smooth muscle cells in the portal vein]

Irradiation of the rat portal vein's fragments with the He-Ne laser for 3, 5 and 10 minutes reduced the fragments tone by half. Frequency of phasic and tonic contractions did not change, their amplitude, however, increased by neatly 40% as compared with the initial level. The NO synthase blocker N-nitro-L-arginine administered prior to the irradiation had no effect on the above parameters. The data obtained suggest that the decrease of the vessel tone is due to production of the EDRF and cGMP. The increase in the amplitude of phasic and tonic contractions of the vein's smooth muscle cells is associated with an increased Ca++ entry in each contraction cycle.

Intraluminal irradiation for TIPS stenosis: preliminary results in a swine model

PURPOSE

To evaluate the ability of 32phosphorus intraluminal irradiation to reduce pseudointimal hyperplasia in a transjugular intrahepatic portosystemic shunt (TIPS).

MATERIALS AND METHODS

TIPS were successfully placed in 11 swine with normal portal pressures. Six animals received 15.2 Gy intraluminal irradiation to the hepatic parenchyma and venous outflow tract at the time of TIPS placement with use of a NA32P-filled balloon angioplasty catheter. Five control animals underwent TIPS and balloon angioplasty with saline. All animals were followed up for 28 days, at which time percutaneous portography was performed, the animals were killed, and the tissue around the TIPS stent was processed for histologic analysis. Maximum pseudointimal hyperplasia as a percentage of estimated TIPS diameter was calculated for each animal.

RESULTS

At the time of euthanasia, all five control TIPS and all but one irradiated TIPS were occluded. Histologic analysis demonstrated considerable variability in the degree of pseudointimal hyperplasia within each TIPS and between animals. No statistically significant difference was found in the maximum pseudointimal hyperplasia, measured as a percentage of stent radius, between control (80.2%+/-17.4%) and irradiated animals (69.2%+/-25.2%).

CONCLUSIONS

Irradiation of TIPS with 15.2 Gy 32P delivered at the time of TIPS placement did not significantly improve TIPS patency or reduce the degree of pseudointimal hyperplasia in swine with normal portal pressures.

Intraoperative irradiation in resected carcinoma of the pancreas and portal vein

We developed a new method that provides a wide retroperitoneal irradiation field for patients with cancer of the pancreas in whom a long invaded portal vein is resected during intraoperative radiotherapy. This method involves the use of a venous bypass with a heparinized catheter that does not require systemic anticoagulation or a pump. Anastomosis is completed after intraoperative radiotherapy. Mean (+/- SD) duration of the venous bypass was 3.0 +/- 1.5 hours (range, 2.0 to 6.6 hours), during which no abnormalities of systemic blood pressure, heart rate, and electrocardiographic activity and no signs of congestion of the intestines were observed. Eleven patients were treated with this method, and no complications ascribed to intraoperative radiotherapy or venous bypass were found. We recommend this method as safe and simple for expanding the irradiation field for intraoperative radiotherapy in patients with pancreatic cancer in whom the portal vein is resected.

Tolerance of canine portal vein anastomosis to intraoperative x-irradiation

Tolerance of surgical portal vein anastomosis to intraoperative radiation therapy (IORT) was studied in dogs after single doses of zero, 10, 20 and 40 Gy (290 kVp x-rays). Portal venography was performed prior to IORT and before sacrificing. The dogs were sacrificed 3 and 12 months respectively after irradiation. Portal venography revealed no radiation induced anastomotic stenosis. Autopsy disclosed macroscopic periportal fibrosis in all dogs, independent of radiation dose and observation periods. Microscopically, the three tunicas of the vein did not show any pathological changes after any dose level.

Tolerance of bile duct to intraoperative irradiation

In order to determine the effects of intraoperative radiation therapy of the bile duct and surrounding tissues, seven adult dogs were subjected to laparotomy and intraoperative irradiation with 11 MeV electrons. Two animals were treated at each dose level of 2000, 3000, and 4500 rads. A single dog which received a laparotomy and sham irradiation served as a control. The irradiation field consisted of a 5 cm diameter circle encompassing the extrahepatic bile duct, portal vein, hepatic artery, and lateral duodenal wall. The animals were followed clinically for mor than 18 months after treatment, and autopsies were performed on dogs that died to assess radiation-induced complications or tissue damage. All dogs developed fibrosis and mural thickening of the common duct, which appeared by 6 weeks following irradiation and which was dose-related, being mild at low doses and more severe at high doses. Hepatic changes were seen as early as 6 weeks after irradiation, consisting of periportal inflammation and fibrosis. The hepatic changes appeared earliest at the highest doses. Frank biliary cirrhosis eventually developed at all dose levels. Duodenal fibrosis appeared in the irradiation portal, being most severe at the highest doses and in some animals resulting in duodenal obstruction. No changes were observed in irradiated portions of portal vein and hepatic artery at any dose level. It was concluded that intraoperative radiation therapy delivered to the region of the common duct leads to ductal fibrosis, partial biliary obstruction with secondary hepatic changes, and duodenal fibrosis if bowel wall is included in the field. Clinical use of intraoperative radiation therapy to the bile duct in humans may require routine use of biliary and duodenal bypass to prevent obstructive complications.