Akihiro Toyosaka

Prognostic factors after hepatectomy for hepatocellular carcinomas. A univariate and multivariate analysis

The current study determines the prognostic factors after hepatectomy for hepatocellular carcinomas. The 295 patients who underwent hepatectomy from 1973 through 1987 were included for a univariate and a Cox multivariate analysis. The favoring conditions were determined as follows. The essential requirements are (1) the absence of tumor thrombi; (2) no intrahepatic metastasis, but even when present, it should be close to the main tumor and removed with a massive resection; and (3) retention rate of indocyanine green dye (ICG) at 15 minutes should be within 14 ± 4.2% (M ± SD) to allow that resection. The desired requirement is that the tumor size should preferably be less than 5 cm; a wider free margin from tumors (⩾ 1 cm) is recommended, but not determining factor. The eligible patients, having no thrombi, no intrahepatic metastasis, a tumor size of 5 cm or less, negative surgical margin (⩾ 1 cm), had achieved a 5‐year survival of 78%. In conclusion, resection therapy is the first option for patients with those requirements.

Do the tumor cells of hepatocellular carcinomas dislodge into the portal venous stream during hepatic resection

Background. The current study was undertaken to investigate whether or not tumor cells are dislodged into the portal venous stream during hepatic resection for hepatocellular carcinomas.

Flow Cytometric DNA Analysis of Hepatocellular Carcinoma

Prognostic value of nuclear DNA content was studied retrospectively using flow cytometry in 203 cases of resected hepatocellular carcinoma. The occurrence of DNA aneuploidy, which was detected in 50% of patients, correlated significantly with tumor size and the presence of vascular invasion or intrahepatic metastasis. Overall, patients with DNA aneuploid tumors had a significantly worse prognosis than those with DNA diploid tumors (P < 0.001) and, also in subdivided groups by tumor size (P < 0.01). Among DNA aneuploid patients, the survival times were significantly shorter for patients with a low DNA index (< 1.5) than for those with a high DNA index (≥1.5) (P < 0.05). In a Cox multivariate analysis, nuclear DNA content provided significant prognostic value (P = 0.008), as did vascular invasion (P = 0.001) and intrahepatic metastasis (P = 0.005). These results indicated that nuclear DNA content has an important prognostic value in hepatocellular carcinoma.

Expression of the intermediate filament nestin in gastrointestinal stromal tumors and interstitial cells of Cajal.

It has recently been proposed that gastrointestinal stromal tumors (GISTs) originate from stem cells that differentiate toward a phenotype of interstitial cells of Cajal (ICCs). Nestin is a newly identified intermediate filament protein, and is predominantly expressed in immature cells, such as neuroectodermal stem cells and skeletal muscle progenitor cells, and tumors originating from these cells. In this study, we examined, using immunohistochemistry, the nestin expression in GISTs and ICCs to clarify the origin of GISTs. Strong immunoreactivity for nestin was observed in all 18 GISTs, and its expression was confirmed by Western blot and Northern blot analyses. In contrast, three leiomyomas and a schwannoma that developed in the gastrointestinal tract showed no apparent immunoreactivity for nestin. Among 17 mesenchymal tumors (seven leiomyosarcomas, five malignant peripheral nerve sheath tumors, and five fibrosarcomas) that occurred in sites other than the gastrointestinal tract, only two malignant peripheral nerve sheath tumors were moderately immunoreactive for nestin. Furthermore, with fluorescence double immunostaining of the normal small intestine, nestin expression was demonstrated in ICCs. These results show that nestin may be a useful marker for diagnosis of GISTs, and support the current hypothesis that GISTs are tumors of stem cells that differentiate toward an ICC phenotype.

Intrahepatic metastases in hepatocellular carcinoma: the role of the portal vein as an efferent vessel.

The mechanism and pathogenesis of the high frequency of intrahepatic metastasis in hepatocellular carcinoma (HCC) has not yet been elucidated. Two hundred and thirty one tumors (⩽ 5 cm in diameter) of resected specimens of HCC were examined for the relationship between mode of tumor spread and tumor size. Efferent vessels in HCC were identified by direct injection of radiopaque material into the tumor in 23 resected liver specimens selected at random from the 231 tumors. The most frequent site for tumor spread in HCC was capsular invasion followed by extracapsular invasion, vascular invasion, and finally intrahepatic metastasis. There was a strong statistical correlation between the presence of intrahepatic metastasis and the frequency of vascular invasion (correlation coefficient = 0.998). Radiopaque material injected directly into 23 resected tumors entered only the portal vein in 17 tumors and into both the portal and hepatic veins in six tumors. In all eight patients with unresectable lesions, radiopaque media injected percutaneously into tumor nodules flowed only into the portal vein. These findings suggest that tumor spread in HCC progresses from capsular invasion to intrahepatic invasion and that the portal vein may act as an efferent tumor vessel.

Current Status of Hepatic Resection in the Treatment of Hepatocellular Carcinoma

Most patients suffering from hepatocellular carcinoma (HCC) in Japan have associated liver cirrhosis or a related liver disease. In the past, massive hepatic resection in these patients applied to cure the HCC frequently resulted in a fatal liver failure postoperatively. Preoperative assessment to determine a safe limit for resection is the most urgent problem for liver surgeons in Japan [1].

Extensive dissection at the porta hepatis for biliary atresia

Dissection at the porta hepatis is the crucial step in surgery for biliary atresia. The authors describe their procedure for extensively dissecting the porta hepatis. The technique is based on an anatomic cast corrosion of the human liver, and the portal vein serves as the landmark for dissection. Lateral dissection at the hepatic hilus is critical to the procedure. On the right side, the anterior portal branches are dissected to the bifurcation of the S5 and S7 segmental portal branches, over the bifurcation of the anterior and posterior portal branches. On the left side, the liver parenchyma, which bridges the umbilical point, is sectioned, and the left portal branch is dissected to the umbilical point over the pars transversalis and taped. The fibrous mass that lies within the confines of the portal branches, including the dorsal aspect, is transected completely. This procedure was performed in 16 infants; the jaundice cleared in 93.7%.

Outcome of 21 patients with biliary atresia living more than 10 years

The outcome of 21 survivors (8 males, 13 females; age range, 11 to 29 years) followed for > 10 years after surgery for biliary atresia are discussed. Of the 21 patients, 18 with type III disease had hepatic portoenterostomy (Kasai operation), and 3 with type I disease had hepaticoenterostomy. Twenty patients are alive leading almost normal lives; however, 13 (61.9%) patients did have a history of complications, including hemorrhage from esophageal varices in 10, from a gastric ulcer or erosion in 3, and from a duodenal ulcer in 2; biliary reobstruction in 3; and multiple pulmonary arteriovenous fistulae in 2. Of those with complications, 7 required surgery. One died suddenly at the age of 19 years of a bleeding gastric ulcer. Liver function is normal in 9 (45.0%) of the 20 alive patients, 2 (10.0%) have slight hepatic dysfunction, and 9 (45.0%) have mild-to-moderate hepatic dysfunction. Liver function is almost normal in 3 patients who had a history of variceal hemorrhage.

Pathologic and Radiographic Studies of Intrahepatic Metastasis Hepatocellular Carcinoma; The Role of Efferent Vessels

The efferent vessel of hepatocellular carcinoma (HCC) and the mechanism and pathogenesis of the high frequency of intrahepatic metastasis in HCC has not yet been clarified. Three hundred ninety-three resected specimens of HCC were examined for tumor thrombosis in the portal vein and the hepatic vein: 231 tumors ≤5 cm in diameter were examined for the relationship between mode of tumor spread and tumor size. Efferent vessels in HCC were identified by direct injection of radiopaque material into the tumor in 23 resected liver specimens and by percutaneous infusion of radiopaque media into tumor nodules in 8 patients. The mode of tumor spread in HCC progressed from capsular invasion to extracapsular invasion, then to vascular invasion, and finally to intrahepatic metastasis. There was a strong statistical correlation between the presence of intrahepatic metastasis and portal vein thrombosis (p<0.05, R=0.998). Radiopaque material injected directly into 23 resected tumors entered only the portal vein in 17 tumors and into both the portal and hepatic veins in 6 tumors. In all 8 patients with unresectable lesions, radiopaque media injected percutaneously into tumor nodules flowed only into the portal vein. These findings suggest that intrahepatic invasion by HCC may occur through the portal vein as an efferent tumor vessel.

THE ROLE OF OVAL CELLS IN RAT HEPATOCYTE TRANSPLANTATION

BACKGROUND Oval cells are liver cells capable of differentiating into either hepatocytes or biliary epithelial cells. We compared growth of hepatocytes and biliary epithelial cells between spleens transplanted with oval cell-free and oval cell-enriched rat liver cells. METHODS Oval cell-enriched liver cells were obtained from livers of adult rats that had undergone treatment with acetylaminofluorene and partial hepatectomy, although oval cell-free liver cells were obtained from livers of untreated rats. Hepatocyte and biliary epithelial cell growth in the spleen was evaluated by counting periodic acid-Schiff-positive cells and cytokeratin 19-positive cells respectively in sections from transplanted spleens. RESULTS Spleens transplanted with oval cell-free liver cells and spleens transplanted with oval cell-enriched liver cells contained similar numbers of hepatocytes after 2 weeks. Numbers of hepatocytes in spleens transplanted with oval cell-free liver cells decreased markedly at 4 and 8 weeks, then increasing slightly until 32 weeks. In spleens transplanted with oval cell-enriched liver cells, numbers of hepatocytes decreased only slightly at 4 weeks and then increased markedly. At 4, 8, 12, 16, 24, and 32 weeks, numbers of hepatocytes in spleens transplanted with oval cell-enriched liver cells respectively were 2.3, 3.5, 4.5, 6.7, 6.3, and 15.1 times hepatocyte numbers in spleens transplanted with oval cell-free liver cells. Numbers of biliary epithelial cells in spleens receiving oval cell-enriched liver cells showed changes similar to those in spleens transplanted with oval cell-free liver cells, increasing markedly at 4 weeks and then markedly and rapidly decreasing. CONCLUSIONS Intrasplenic transplantation of oval cell-enriched liver cells enhanced growth of hepatocytes compared with transplantation of oval cell-free liver cells; this was not true for biliary epithelial cells.