Therapeutic aspects of radio-isotopes in hepatobiliary malignancy

Radioembolization for the Treatment of Primary and Metastatic Liver Cancers

Radioembolization using ⁹⁰Y microspheres (glass or resin) has been introduced as an effective intraarterial therapy for unresectable primary and metastatic liver cancers. Although the basic therapeutic effect of chemoembolization results from ischemia, the therapeutic efficacy of radioembolization comes from radiation. Furthermore, compared with surgical resection and local ablation therapy, radioembolization is available with less limitation on the sites or number of liver cancers. The radioisotope ⁹⁰Y is a β-radiation emitter without γ-radiation, with the emission of secondary bremsstrahlung photons and small numbers of positrons. Administration of ⁹⁰Y microspheres into the hepatic artery can deliver a high dose of radiation selectively to the target tumor with limited radiation exposure to the surrounding normal parenchyma, and has low systemic toxicity. In general, radioembolization has been considered for patients with unresectable primary or metastatic liver-only or liver-dominant cancers with no ascites or other clinical signs of liver failure, life expectancy of > 12 weeks, and good performance status. Here, we review the current radioactive compounds, pretreatment assessment, and indications for radioembolization in patients with hepatocellular carcinoma, intrahepatic cholangiocarcinoma, and liver metastases from colorectal cancer.

Splenomegaly-associated thrombocytopenia after hepatic yttrium-90 radioembolization

PURPOSE

Thrombocytopenia is often observed after yttrium-90 radioembolization (RE). Possible mechanisms include radiation toxicity to the bone marrow, consumption in the liver due to local radiation effects, and sequestration in the spleen. We sought to identify the causative factors.

MATERIALS AND METHODS

Patients with complete baseline and 3-month post-RE imaging and laboratory data were included in this retrospective analysis. Univariate and multivariate regression analyses were performed on clinical, procedural, and imaging data.

RESULTS

A total of 116 patients were identified (65 male, 51 female; median age 64 years). Forty-six patients were treated for primary and 70 for metastatic liver malignancy. Of these, 86 were treated with resin and 30 with glass microspheres; median activity was 1.85 GBq. Eighty-three patients underwent whole-liver treatment. Maximum individual change in platelet count was -20.2 % leading to new or increased grade of thrombocytopenia in 48 patients (41.4 %) by National Cancer Institute Common Toxicity Criteria for Adverse Events version 4.02 criteria. Independent risk factors for decreased platelet count included change in spleen volume (median change +17.5 %; p = 0.001) and whole-liver (rather than lobar or segmental) treatment (p = 0.025). Administered activity and absorbed dose were not associated with change in platelet count. The change in spleen volume itself was associated with previous epidermal growth factor receptor-inhibitor treatment (p = 0.002), whole-liver absorbed dose (p = 0.027), and multiple-line chemotherapy (0.012) for whole-liver treatments only.

CONCLUSION

Post-RE treatment increase of spleen volume is correlated with decreased peripheral platelet count suggesting a mechanism of increased portal hypertension and hypersplenism being responsible.

Profound transient thrombocytopenia associated with 90Yttrium microsphere therapy for inoperable hepatoma

The use of Yttrium microspheres to treat unresectable hepatoma is increasing worldwide. Therapeutically, Yttrium microspheres show promising increases in survival and tumor response, as well as acceptable toxicities. Here, we report on a 67-year-old man with hepatitis C-related advanced-stage hepatoma. This patient received selective internal radiation therapy (SIRT) using Yttrium microspheres (SIR-Spheres®). The patient displayed bone marrow suppression that resulted in a transient yet profound thrombocytopenia. To our knowledge, this is the first case of a hematologic complication as a consequence of the use of commercially available Yttrium microsphere devices.

Biliary complications associated with selective internal radiation (SIR) therapy for unresectable liver malignancies

Selective internal radiation (SIR) therapy using 90yttrium microspheres is effective for treating selected cases of unresectable liver malignancies with little morbidity. We herein report two cases illustrating a very rare complication of SIR. A 68-year-old patient with inoperable recurrent hepatocellular carcinoma received one treatment of SIR with 90yttrium microspheres and 4 months later presented with obstructive jaundice. Percutaneous transhepatic cholangiography revealed diffusely dilated intrahepatic ducts with multiple biliary strictures. Hepatic angiography showed normal hepatic arterial branches with no evidence of vascular insufficiency. Liver biopsy finally revealed cholestasis, cholangitis, and fibrosis, consistent with radiation-induced damage. Another 56-year-old patient with unresectable colorectal liver metastases presented with cholangitis 4 weeks after SIR. Ultrasonography showed no biliary dilatation, and endoscopic retrograde cholangiopancreatography demonstrated a normal biliary tree. Liver biopsy subsequently confirmed radiation-induced cholangitis.

Uptake of Lipiodol--cytotoxic conjugates by hepatoblastoma cells

BACKGROUND

Improvements in the management of children with hepatoblastoma have followed advances made in cytotoxic agents and treatment regimens. The aim of this study was to quantify the effect of Lipiodol, an iodinated poppy-seed oil, on the uptake of anthracyclic cytotoxic conjugates by hepatoblastoma cells in culture.

METHODS

Monolayer cultures of (1) a hepatoblastoma cell line generated from freshly explanted tumour tissue, (2) an immortal hepatoblastoma cell line (C3a) and (3) a human hepatocyte cell line were exposed to doxorubicin 10 microg/ml with or without 2 per cent Lipiodol for 1-72 h. The fluorescence intensity in the treated cells, which correlates with intracellular doxorubicin concentration, was measured by confocal laser scanning microscopy. Cytotoxicity was assessed by trypan blue exclusion and electron microscopy.

RESULTS

Doxorubicin accumulated in the nucleus and cytoplasm of all the cell lines. With Lipiodol, the mean fluorescence intensity of intracellular doxorubicin was increased for up to 48 h in both hepatoblastoma lines, but not in the hepatocyte cell line. Lipiodol increased the uptake and intracellular concentration of doxorubicin in the hepatoblastoma cells in culture. Lipiodol also enhanced the cytotoxicity of doxorubicin on the cultured hepatoblastoma cells.

CONCLUSION

Lipiodol significantly enhanced the uptake of doxorubicin by hepatoblastoma cells in culture. Lipiodol-doxorubicin targeted treatment of hepatoblastoma may improve the intracellular uptake and hence cytotoxicity of doxorubicin in vivo, enabling a reduction in the total dose administered and side-effects.

Lipiodol uptake and retention by human hepatoma cells

Lipodol has important diagnostic and therapeutic uses in hepatoma. However, the mechanisms of its selective, prolonged retention in hepatoma cells is not well understood. Therefore, using oil-red O, light and electron microscopy and neutron activation analysis we have determined that HepG2 cells are characterized by lipiodol deposition and emulsification on the cell surface, action uptake of lipodol by endocytosis, and prolonged intracellular retention. These findings may have major clinical significance in the development of a new treatment for hepatoma patients.

Treatment of inoperable hepatocellular carcinoma with intrahepatic arterial yttrium-90 microspheres: a phase I and II study

Eighteen patients with inoperable hepatocellular carcinoma (HCC) were treated with intrahepatic arterial yttrium-90 microspheres. All these patients showed a lung shunting below 15% and a tumour-to-normal ratio higher than 2 as determined by diagnostic technetium-99m macroaggregated albumin (Tc-MAA) gamma scintigraphy. The treatment was given through an arterial port placed during laparotomy. The radiation doses to the liver and tumour were determined intraoperatively with a beta probe and liquid scintillation counting of multiple liver biopsies. The treatment was well tolerated without major complications. In all patients the tumour marker fell to a level which ranged from 41% to 0.2% of the pretreatment level. Tumour regression was found to be dose related. Progressive or static disease occurred in a higher proportion of patients whose tumours received < 120 Gy (P = 0.005). Survival was better in those whose tumours received > 120 Gy (median survival = 55.9 weeks) than those whose tumours received lower doses (median survival = 26.2 weeks). This difference is statistically significant with P = 0.005. We conclude that yttrium-90 microsphere therapy is safe and that tumour response is dose related. A tumour dose of > 120 Gy is recommended.

Case report: hepatocellular carcinoma diagnosed radiologically, treated by transcatheter arterial embolization and limited-field radiotherapy

Even though the resection rate for hepatocellular carcinoma (HCC) has risen recently, many patients cannot be treated surgically because of the advanced stage of the tumour and/or coexisting cirrhosis. An alternative therapeutic approach for some of these patients is transcatheter arterial embolization (TAE) which has become very common in Japan. However, it is not a curative measure, and an additional therapy is required to eradicate the residual disease. In this communication, we report a case in which a patient with HCC has been successfully treated by TAE followed by limited-field radiotherapy. The results suggest that this is a very promising therapeutic approach for HCC and that the potential of limited-field radiotherapy for HCC with or without TAE also needs to be explored.

Cytoreductive surgery for hepatocellular carcinoma

A prospective study was conducted on 26 patients for cytoreductive surgery of inoperable hepatocellular carcinoma. These patients underwent cytoreduction with liver resection, cryosurgery, microwave tissue coagulation and/or absolute alcohol injection. In-hospital mortality was 7.7%. The symptomatic relief and quality of survival were excellent. The median survival of patients after cytoreduction was 10.0 months and the survival was much better than those of 26 patients matched by sex, age, tumour size, Child-Pugh grading and Karnofsky scores who received systemic chemotherapy during the same period of the study (log rank test, P = 0.0001). There was no statistical difference between the survival curves of those patients who received (19 patients) and those who did not receive (7 patients) additional treatment by chemotherapy or selective internal radiation therapy after cytoreduction. This suggests that the gained survival benefit could have been derived mainly from the cytoreductive surgery rather than the additional treatments.

Diagnostic pharmaco-scintigraphy with hepatic intra-arterial technetium-99m macroaggregated albumin in the determination of tumour to non-tumour uptake ratio in hepatocellular carcinoma

Between October 1990 and March 1993, 124 patients who had hepatocellular carcinoma (HCC) underwent diagnostic pharmaco-scintigraphy with hepatic intraarterial technetium-99m macroaggregated albumin (TcMAA) to determine the tumourous to non-tumourous liver tissue uptake ratio (T/N ratio). There were 110 males and 14 females. Ages ranged from 16 to 73 with a median of 55 years. The range of T/N ratio was 0.7 to 19.3 with a median of 3.8. 12 patients with inoperable HCC were subsequently selected by predetermined criteria to undergo treatment with hepatic intraarterial yttrium-90 microspheres and the T/N ratios in these patients were validated by beta probe dosimetry and liquid scintillation count of multiple liver biopsies. The T/N ratio determined by preoperative diagnostic TcMAA scan correlated well with intraoperative beta probe dosimetry, with coefficient of correlation r = 0.82. Preoperative TcMAA scan also correlated well with liquid scintillation count of biopsy specimens, with r = 0.96. We conclude that TcMAA scan can be used to determine the T/N ratio in patients with HCC, thus allowing better selection of patients with inoperable tumours for loco-regional therapy.

Natural history of hepatocellular carcinoma and prognosis in relation to treatment. Study of 850 patients

A total of 850 patients with hepatocellular carcinoma seen during the last 8 years were analyzed retrospectively for survival in relation to treatment and disease stage. A new staging scheme based on tumor size, ascites, jaundice and serum albumin was used. Clearly, the prognosis depended on disease stage. The median survival of 229 patients who received no specific treatment was 1.6 months, 0.7 month for Stage III patients, 2.0 months for Stage II, and 8.3 months for Stage I. The median survival of Stage I patients who had hepatic resection (n = 115) was 25.6 months and Stage II patients with resection (n = 42) was 12.2 months. In patients who had a small cancer (less than or equal to 25% of liver area in size) the median survival was 29.0 months. Survival of the surgically treated patients, which represented a highly selected group, was better than that of medically treated patients of a comparable stage. Median survival of Stage I medically treated patients (n = 124) was 9.4 months, for Stage II (n = 290) 3.5 months, and for Stage III (n = 50) 1.6 months. Medical treatment prolonged survival in Stage II and III patients, but not in Stage I. Transcatheter arterial embolization gave a better survival compared with chemotherapy, whether intra-arterial bolus administration of mitomycin C, systemic mitomycin C, or oral/rectal tegafur, in Stage II. Among various chemotherapeutic modalities, intra-arterial bolus injection was superior to systemic chemotherapy in survival in Stage II. In Stage III, chemotherapy improved survival as compared with no specific treatment. The major causes of death were hepatic failure and gastrointestinal bleeding, probably due to the coexistent advanced cirrhosis. These results in survival are much improved over the past reports, and the differences are probably a result of earlier diagnosis and frequent hepatic resections.