Takao Kawabe

Percutaneous radiofrequency ablation for hepatocellular carcinoma. An analysis of 1000 cases.

Radiofrequency ablation (RFA) was introduced recently as a therapeutic modality for hepatocellular carcinoma (HCC), an alternative to percutaneous ethanol injection therapy (PEIT), which is coming into use worldwide. Previously reported treatment efficacy and complication rates have varied considerably.

A prospective randomised study of “covered” versus “uncovered” diamond stents for the management of distal malignant biliary obstruction

Background and aim: Covered self-expandable metal stents (EMS) were recently developed to overcome tumour ingrowth in conventional EMS. However, supporting evidence for the efficacy of covered EMS is lacking. Patients and methods: We enrolled 112 patients with unresectable distal biliary malignancies. They were randomly assigned to polyurethane covered (n = 57) or original diamond stent (n = 55). Results: Stent occlusion occurred in eight patients (14%) after a mean of 304 days in the covered group, and in 21 patients (38%) after a mean of 166 days in the uncovered group. The incidence of covered EMS occlusion was significantly lower than that of uncovered EMS (p = 0.0032). The cumulative stent patency of covered stents was significantly higher than that of uncovered stents (p = 0.0066). No tumour ingrowth occurred in the covered group while it was observed in 15 patients in the uncovered group. In subgroup analysis, the cumulative patency of the covered EMS was significantly higher in pancreatic cancer (p = 0.0363) and metastatic lymph nodes (p = 0.0354). There was no significant difference in survival between the two groups. Acute cholecystitis was observed in two of the covered group and in none of the uncovered group. Mild pancreatitis occurred in five of the covered group and in one of the uncovered group. Conclusions: Covered diamond stents successfully prevented tumour ingrowth and were significantly superior to uncovered stents for the treatment of patients with distal malignant biliary obstruction. However, careful attention must be paid to complications specific to covered self-expandable metal stents, such as acute cholecystitis and pancreatitis.

Functional Analysis of PIK3CA Gene Mutations in Human Colorectal Cancer

Mutations in the PIK3CA gene, which encodes the p110alpha catalytic subunit of phosphatidylinositol 3-kinase (PI3K), have been reported in human cancers, including colorectal cancer. Most of the mutations cluster at hotspots within the helical and kinase domains. Whereas H1047R, one of the hotspot mutants, is reported to have elevated lipid kinase activity, the functional consequences of other mutations have not been examined. In this study, we examined the effects of colon cancer-associated PIK3CA mutations on the lipid kinase activity in vitro, activation of the downstream targets Akt and p70S6K in vivo and NIH 3T3-transforming ability. Of eight mutations examined, all showed increased lipid kinase activity compared with wild-type p110alpha. All the mutants strongly activated Akt and p70S6K compared with wild-type p110alpha as determined by immunoblotting using phospho-specific antibodies. These mutants also induced morphologic changes, loss of contact inhibition, and anchorage-independent growth of NIH 3T3 cells. The hotspot mutations examined in this study, E542K, E545K, and H1047R, all had high enzymatic and transforming activities. These results show that almost all the colon cancer-associated PIK3CA mutations are functionally active so that they are likely to be involved in carcinogenesis.

Predicting the development of gastric cancer from combining Helicobacter pylori antibodies and serum pepsinogen status: a prospective endoscopic cohort study

Background and aim:Helicobacter pylori infection and gastric atrophy are both risk factors for gastric cancer. We aimed to elucidate the natural history of gastric cancer development according to H pylori infection and gastric atrophy status. Subjects and methods: A total of 9293 participants in a mass health appraisal programme were candidates for inclusion in the present prospective cohort study: 6983 subjects revisited the follow up programme. Subjects were classified into four groups according to serological status at initial endoscopy. Group A (n = 3324) had “normal” pepsinogen and were negative for H pylori antibody; group B (n = 2134) had “normal” pepsinogen and were positive for H pylori antibody; group C (n = 1082) had “atrophic” pepsinogen and were positive for H pylori antibody; and group D (n = 443) had “atrophic” pepsinogen and were negative for H pylori antibody. Incidence of gastric cancer was determined by annual endoscopic examination. Results: Mean duration of follow up was 4.7 years and the average number of endoscopic examinations was 5.1. The annual incidence of gastric cancer was 0.04% (95% confidence interval (CI) 0.02–0.09), 0.06% (0.03–0.13), 0.35% (0.23–0.57), and 0.60% (0.34–1.05) in groups A, B, C, and D, respectively. Hazard ratios compared with group A were 1.1 (95% CI 0.4–3.4), 6.0 (2.4–14.5), and 8.2 (3.2–21.5) in groups B, C, and D, respectively. Age, sex, and “group” significantly served as independent valuables by multivariate analysis. Conclusions: The combination of serum pepsinogen and anti-H pylori antibody provides a good predictive marker for the development of gastric cancer.

Prospective risk assessment for hepatocellular carcinoma development in patients with chronic hepatitis C by transient elastography

Liver stiffness, noninvasively measured by transient elastography, correlates well with liver fibrosis stage. The aim of this prospective study was to evaluate the liver stiffness measurement (LSM) as a predictor of hepatocellular carcinoma (HCC) development among patients with chronic hepatitis C. Between December 2004 and June 2005, a total of 984 HCV‐RNA positive patients, without HCC or a past history of it, visited the University of Tokyo Hospital. LSM was performed successfully in 866 patients, who gave informed consent. During the follow‐up period (mean, 3.0 years), HCC developed in 77 patients (2.9% per 1 person‐year). The cumulative incidence rates of HCC at 1, 2, and 3 years were 2.4%, 6.0%, and 8.9%, respectively. Adjusting for other significant factors for HCC development, patients with higher LSM were revealed to be at a significantly higher risk, with a hazard ratio, as compared to LSM ≤10 kPa, of 16.7 (95% confidence interval [CI], 3.71‐75.2; P < 0.001) when LSM 10.1‐15 kPa, 20.9 (95% CI, 4.43‐98.8; P < 0.001) when LSM 15.1‐20 kPa, 25.6 (95%CI, 5.21‐126.1; P < 0.001) when LSM 20.1‐25 kPa, and 45.5 (95% CI, 9.75‐212.3; P < 0.001) when LSM >25 kPa. Conclusions: This prospective study has shown the association between LSM and the risk of HCC development in patients with hepatitis C. The utility of LSM is not limited to a surrogate for liver biopsy but can be applied as an indicator of the wide range of the risk of HCC development. (HEPATOLOGY 2009.)

Radiofrequency ablation for hepatocellular carcinoma in so‐called high‐risk locations

We evaluated the efficacy and safety of radiofrequency (RF) ablation for hepatocellular carcinoma (HCC) in presumably high‐risk locations. Between February 1999 and December 2001, we performed RF ablation on 1,419 nodules in 636 consecutive HCC patients, of which 231 nodules in 207 patients were in high‐risk locations, defined as less than 5 mm from a large vessel or an extrahepatic organ. Eighty‐one patients had a nodule adjacent to a large vessel, 145 patients had a nodule adjacent to an extrahepatic organ, of whom 19 also had one adjacent to a large vessel. Early complications and local tumor progression were analyzed with regard to the location of each nodule. The mean nodule diameter and average number per patient were 27 mm and 2.3, respectively. Early complications, within 30 days after ablation, occurred in 12 of 207 patients (5.8 %) with a nodule in a high‐risk location and in 15 of 429 patients (3.5 %) without (P = .1776). There was no significant difference in local tumor progression rate between nodules in high‐risk locations (1 year: 2.1%, 2 years: 3.1%, 3 years: 3.1%) and those elsewhere (1 year: 0.6%, 2 years: 1.7%, 3 years: 2.5%) (P = .2745). In conclusion, HCC nodules adjacent to a large vessel or extrahepatic organ were treated with RF ablation without compromising the efficacy of the procedure. However, even though without significant difference, some complications occurred at risky locations and need to be carefully considered. (HEPATOLOGY 2006;43:1101–1108.)

Long-term prognosis of autoimmune pancreatitis with and without corticosteroid treatment

Objectives: Autoimmune pancreatitis (AIP) is a unique form of chronic pancreatitis, and has a favourable response to corticosteroid treatment (CST). Little is known, however, about the long-term outcome of AIP. This study aimed to document the prognosis without and with CST, and to examine the indication for CST. Patients and methods: The prognosis and clinical features of 23 patients without CST and 19 patients treated with CST from onset were investigated. In addition, factors concerning the late occurrence of unfavourable events related to AIP were examined. Results: The patients without CST were 19 men and four women, with an average age of 66 years. After an average observation period of 25 months, 16 patients (70%) developed unfavourable events including obstructive jaundice as a result of distal bile duct stenosis in four, growing pseudocyst in one, sclerogenic changes of extrapancreatic bile duct in nine, hydronephrosis as a result of retroperitoneal fibrosis in one, and interstitial nephritis in one. Patients with obstructive jaundice at onset showed a higher cumulative event occurrence rate (p = 0.025). The patients treated with CST were 16 men and three women, with an average age of 64 years. After an average observation period of 23 months, six patients (32%) developed unfavourable events consisting of interstitial pneumonia in three, and a recurrence of obstructive jaundice in three. In multivariate analysis, CST (HR 0.33, 95% CI 0.12–0.89, p = 0.029) and obstructive jaundice at onset (HR 3.09, 95% CI 1.14–8.32, p = 0.026) were significant predictive factors for unfavourable events. Conclusion: CST could reduce AIP-related unfavourable events. The early introduction of CST is recommended especially for patients with obstructive jaundice.

Blockade of the Stromal Cell–Derived Factor-1/CXCR4 Axis Attenuates In vivo Tumor Growth by Inhibiting Angiogenesis in a Vascular Endothelial Growth Factor–Independent Manner

The interaction between the chemokine receptor CXCR4 and its specific ligand, stromal cell-derived factor-1 (SDF-1/CXCL12), mediates several cellular functions. In cancer, SDF-1-positive or CXCR4-positive cells of various lineages are detected within tumor tissues. Recent intensive research has indicated the possibility that blocking CXCR4 could reduce the metastatic potential of cancer cells. Here, we show that the inhibition of the SDF-1/CXCR4 axis decreases the growth of s.c. gastrointestinal tumors through the suppression of tumor neoangiogenesis. The neutralization of CXCR4 suppressed the growth in vivo of tumors derived from mouse Colon38 and PancO2 cells, whereas it did not affect the growth of Colon38 and PancO2 cells in vitro. This attenuation of tumor growth was found to be independent of the expression of CXCR4 by the cancer cells themselves, because CXCR4 knocked-down Colon38 cells grew similarly to control cells. Furthermore, CD31-positive tumor capillaries were reduced to 45% (P < 0.001) and intratumor blood flows were decreased to 65% (P < 0.01) by blockade of CXCR4. The vascular endothelial growth factor (VEGF) concentration in the tumors was not affected by the neutralization of CXCR4. Taken together with the detection of CXCR4-positive endothelial cells in the tumor tissues, the findings suggest that the antiangiogenic effects of the blockade of CXCR4 are related to a reduction of the establishment of tumor endothelium independently of VEGF inhibition. Our data indicate that the SDF-1/CXCR4 pathway might be a general target for anticancer strategies and that blocking this system could be cooperatively effective in combination with other antiangiogenic therapies, such as blockade of VEGF.

Involvement of the biliary system in autoimmune pancreatitis: a follow-up study

BACKGROUND & AIMS The aim of this study was to define the bile duct changes associated with autoimmune pancreatitis. METHODS Eight patients with autoimmune pancreatitis were followed for a mean of 4 years. The clinical features of these patients, including extrapancreatic bile duct changes, were examined by using biochemical parameters and several imaging modalities. Pathologic features of the pancreas and liver were examined by using the biopsy specimens of 7 patients. RESULTS Diffuse or focal narrowing of the main pancreatic duct was observed in all patients. Histologic examination of the pancreas showed lymphoplasmacyte infiltration with severe fibrosis and acinar cell depletion. In 6 patients extrapancreatic bile duct changes such as stricture of the bile duct at hilus or intrahepatic area were observed. In 2 patients abnormalities in the bile duct and pancreas were detected simultaneously at diagnosis, and changes in the bile duct were observed later in 4 patients. Lymphoplasmacyte infiltration and fibrosis were observed in the portal area of all 7 liver biopsy samples. Five of the patients with bile duct changes received steroid therapy, and the pathological changes improved. CONCLUSIONS Extrapancreatic bile duct changes are frequently associated with autoimmune pancreatitis. Similar pathogenic mechanism might produce the biliary tract and pancreatic abnormalities in autoimmune pancreatitis resulting in a similar histopathology in the liver and pancreas and response to steroid therapy.

Measurement of radial and axial forces of biliary self-expandable metallic stents

BACKGROUND Efforts to understand the properties of self-expandable metallic stents (SEMSs) through their mechanical properties have progressed. Among them, radial force (RF) is well known as an expanding force, but axial force (AF) has not been measured before. Correlations of these properties to clinical results are not well known. OBJECTIVE We measured RF and AF of 14 different SEMSs and discussed the results in terms of clinical implications. DESIGN Experimental study. SUBJECTS Measurement of RF and AF of 14 different covered and uncovered SEMSs. METHODS RF was measured with an RF measurement machine manufactured by Machine Solution, and AF was measured with in-house equipment. RESULTS Measurements of RF in the process of expansion showed characteristic patterns closely related to the structures and materials of SEMSs. Results of AF measurement can be classified into 3 groups: high, medium, and low AF, depending on the type of SEMS. AF decreased with an increase of the length of stents. A plot of RF against AF revealed 3 distinguished RF/AF combinations and indicated the importance of understanding the properties by not only RF or AF individually but also by RF/AF combination. LIMITATIONS In vitro study using measurement equipment. CONCLUSION It was demonstrated that a combination of RF and AF is more effective than RF or AF individually in understanding the clinical implications of SEMSs. More work is needed to correlate mechanical properties with clinical results by designing model experiments.