Treatment of asymptomatic metastatic cancer to the liver from primary colon and rectal cancer by the intraarterial administration of chemotherapy and radioactive isotopes

Standard Radiation Dosimetry Models: What Interventional Radiologists Need to Know

Thoughtful and accurate dosimetry is critical to obtain the safest and most efficacious yttrium-90 (Y90) radioembolization of primary and secondary liver cancers. Three dosimetry models are currently used in clinical practice, namely, body surface area model, medical internal radiation dose model, and the partition model. The objective of this review is to briefly outline the history behind Y90 dosimetry and the difference between the aforementioned models. When applying these three models to a single case, the differences between them are further demonstrated. Each dosimetry model in clinical practice has its own benefits and limitations. Therefore, it is incumbent upon practicing interventional radiologists to be aware of these differences to optimize treatment outcomes for their patients.

Radioembolisation of hepatocellular carcinoma: a primer

Transarterial radioembolisation (TARE) has gained increasing acceptance as an additional/alternative locoregional treatment option for hepatocellular carcinoma, and colorectal hepatic metastases that present beyond potentially curative options. This is a catheter-based transarterial selective internal brachytherapy that involves injection of radioactive microspheres (usually Y-90) that are delivered selectively to the liver tumours. Owing to the combined radioactive and microembolic effect, the findings at follow-up imaging are significantly different from that seen with other transarterial treatment options. Considering increasing confidence among clinicians, refinement in techniques and increasing number of ongoing trials, TARE is expected to gain further acceptance and become an important tool in the armamentarium for the treatment of liver malignancies. So it is imperative that all radiologists involved in the management of liver malignancies are well versed with TARE to facilitate appropriate discussion at multidisciplinary meetings to direct further management. In this article, we provide a comprehensive review on various aspects of radioembolisation with Y-90 for hepatocellular carcinoma including the patient selection, treatment planning, radiation dosimetry and treatment, side effects, follow-up imaging and future direction.

The development, commercialization, and clinical context of yttrium-90 radiolabeled resin and glass microspheres

Selective internal radiation therapy has emerged as a well-accepted therapeutic for primary and metastatic hepatic malignancies. This therapeutic modality requires the combined efforts of multiple medical disciplines to ensure the safe delivery of yttrium-90 (90Y)-labeled microspheres. The development of this therapy followed decades of clinical research involving tumor vascularity and microsphere development. Today, it is essential that treating physicians have a thorough understanding of hepatic tumor vascularity and 90Y microsphere characteristics before undertaking this complex intervention. This review explores the contributions of early investigators of this therapy, as well as the development, US Food and Drug Administration approval, manufacturing process, and attributes of the 2 commercially available 90Y radiolabeled microsphere device to clarify the key physical differences between the products.

Yttrium-90 Glass Microspheres Injected VIA the Portal Vein

Nondegradable glass microspheres (35 μ) were injected into the portal vein for toxicity test in 15 rabbits. In 10 animals the microspheres were loaded with 90Y, giving liver absorbed doses between 24.6 and 437.4 Gy, and in 5 with 89Y (control group). The total amount of microspheres injected in each animal varied between 35 and 140 mg. The rabbits in the experimental group tolerated the effect of radioembolization in a dose 4 times higher than the upper limit of the clinical dose (100 Gy). After injection of 90Y glass microspheres into the portal vein of rats with diethylnitrosamine (DEN)-induced hepatic carcinoma, the microspheres, in addition to the liver parenchyma, accumulated in central and peripheral parts of the cancer nodules, causing necrosis. The internal radiation therapy of 90Y glass microspheres delivered via the portal vein may be an effective nonsurgical method for the treatment of liver cancer, especially in small nodules.

Yttrium-90 hepatic radioembolization: clinical review and current techniques in interventional radiology and personalized dosimetry

In recent years, yttrium-90 ((90)Y) microsphere radioembolization has been establishing itself as a safe and efficacious treatment for both primary and metastatic liver cancers. This extends to both first-line therapies as well as in the salvage setting. In addition, radioembolization appears efficacious for patients with portal vein thrombosis, which is currently a contraindication for surgery, transplantation and transarterial chemoembolization. This article reviews the efficacy and expanding use of (90)Y microsphere radioembolization with an added emphasis on recent advances in personalized dosimetry and interventional radiology techniques. Directions for future research into combination therapies with radioembolization and expansion into sites other than the liver are also explored.

Yttrium-90 microsphere-selective internal radiation therapy with chemotherapy (chemo-SIRT) for colorectal cancer liver metastases: an in vivo double-arm-controlled phase II trial

OBJECTIVES

Selective internal radiation therapy (SIRT) with yttrium-90 (Y) microspheres has emerged as an effective liver-directed therapy with a favorable therapeutic ratio for treatment of colorectal cancer liver metastases. The aim of this study was to investigate the objective responses obtained by Y microsphere treatment when combined with contemporary chemotherapy in the front-line (first or second line) setting in patients with CRCLM.

METHODS

This study used an in vivo comparison between the right and left liver lobes; systemic chemotherapy was supplied to both liver lobes by virtue of systemic administration, whereas SIRT was administered selectively to the target liver lobe only. Response to treatment was evaluated by serial fludeoxyglucose positron emission tomography computed tomography performed at 4 weeks, 2 to 4 months, and 6 to 8 months. Standard uptake value, anatomic volume, functional tumor volume, and total lesion glycolysis (TLG) calculations were obtained at each time point.

RESULTS

A decrease in TLG on fludeoxyglucose positron emission tomography computed tomography imaging was seen in 19 of the 20 patients. The mean decrease in TLG values in the tumors receiving chemo-SIRT and chemo-only treatment were 86.26%±18.57% and 31.74%±80.99% (P<0.01), 93.13%±11.81% and 40.80%±73.32% (P=0.01), and 90.55%±19.75% and 54.91%±38.55% (P<0.01) at 4 weeks, 2 to 4 months, 6 to 8 months posttreatment, respectively. Functional and anatomic tumor volume changes were in concordance with the TLG changes.

CONCLUSIONS

The study demonstrated that, under near identical conditions in terms of patient and tumor characteristics, the chemo-SIRT combination produced superior objective responses compared with chemo-only treatment in a front-line treatment setting in patients with colorectal cancer liver metastases.

Yttrium-90 (90Y) in the principal radionuclide therapies: an efficacy correlation between peptide receptor radionuclide therapy, radioimmunotherapy and transarterial radioembolization therapy. Ten years of experience (1999-2009)

The clinical application of the pure beta emitter (90)Y constitutes a fundamental advancement in non-invasive medicine. Nowadays, mainly three oncological therapies exploit the intrinsic emissive characteristic of (90)Y. Radionuclide therapies include peptide receptor radionuclide therapy (PRRT) in neuroendocrine tumour (NET) treatment, radioimmunotherapy (RIT) in non-Hodgkin's lymphoma (NHL) treatment and transarterial radioembolization therapy (TARET) in unresectable hepatocellular carcinoma (HCC) and liver metastatic colorectal cancer (mCRC) treatment. The last ten years of clinical experience from E-PubMed research have been reviewed and an efficacy correlation between (90)Y-therapies has shown a better objective response rate for RIT (ORR 80±15%; range 53-100) compared to PRRT (ORR 23.5±14%; range 9-50), and TARET (ORR for mCRC, 40±25%; range 19-91, and ORR for HCC, 42±20%; range 20-82). This review reports on the state of the art of the efficacy of (90)Y-therapies from the last decade and discusses new perspectives of therapeutic development.

Selective internal radiation therapy with SIR-spheres for the treatment of unresectable colorectal hepatic metastases

The purpose of this study was to evaluate the effectiveness of colorectal cancer (CRC) liver metastasis radioembolization with yttrium-90 (Y90), assessing toxicity and survival rates in patients with no response to chemotherapy through our 3-year experience. From February 2005 to January 2008, we treated 41 patients affected by CRC from a cohort of selective internal radiation therapy patients treated at our institution. All patients examined showed disease progression and arrived for our observation with an abdominal CT, a body PET, and a hepatic angiography followed by gastroduodenal artery coiling previously performed by us. We excluded patients with a bilirubin level>1.8 mg/dl and pulmonary shunt>20% but not patients with minor extrahepatic metastases. On treatment day, under fluoroscopic guidance, we implanted a dose of Y90 microspheres calculated on the basis of liver tumoral involvement and the body surface area formula. All patients were discharged the day after treatment. We obtained, according to Response Evaluation Criteria on Solid Tumors, a complete response in 2 patients, a partial response in 17 patients, stable disease in 14 patients, and progressive disease in 8 patients. In all cases, we obtained a carcinoembryonic antigen level decrease, especially in the week 8 evaluation. Technical success rate was 98% and technical effectiveness estimated at 3 months after treatment was 80.5%. Side effects graded by Common Terminology Criteria on Adverse Events were represented by one grade 4 hepatic failure, two grade 2 gastritis, and one grade 2 cholecystitis. The median survival and the progression-free survival calculated by Kaplan-Meier analysis were 354 and 279 days, respectively. In conclusion, according to our 3-year experience, Y90 SIR-Spheres radioembolization is a feasible and safe method to treat CRC liver metastases, with an acceptable level of complications and a good response rate.

Safety and efficacy of Y-90 microsphere treatment in patients with primary and metastatic liver cancer: the tumor selectivity of the treatment as a function of tumor to liver flow ratio

BACKGROUND

Treatment records and follow-up data on 40 patients with primary and metastatic liver malignancies who underwent a single whole-liver treatment with Y-90 resin microspheres (SIR-Spheres Sirtex Medical, Lake Forest, IL) were retrospectively reviewed. The objective of the study was to evaluate the anatomic and physiologic determinants of radiation dose distribution, and the dose response of tumor and liver toxicity in patients with liver malignancies who underwent hepatic arterial Y-90 resin microsphere treatment.

METHODS

Liver and tumor volume calculations were performed on pre-treatment CT scans. Fractional tumor and liver flow characteristics and lung shunt fractions were determined using hepatic arterial Tc-99m MAA imaging. Absorbed dose calculations were performed using the MIRD equations. Liver toxicity was assessed clinically and by liver function tests. Tumor response to therapy was assessed by CT and/or tumor markers.

RESULTS

Of the 40 patients, 5 had hepatocellular cancer (HCC), and 35 had metastatic liver tumors (15 colorectal cancer, 10 neuroendocrine tumors, 4 breast cancer, 2 lung cancer, 1 ovarian cancer, 1 endometrial cancer, and 2 unknown primary adenocarcinoma). All patients were treated in a salvage setting with a 3 to 80 week follow-up (mean: 19 weeks). Tumor volumes ranged from 15.0 to 984.2 cc (mean: 294.9 cc) and tumor to normal liver uptake ratios ranged from 2.8 to 15.4 (mean: 5.4). Average administered activity was 1.2 GBq (0.4 to 2.4 GBq). Liver absorbed doses ranged from 0.7 to 99.5 Gy (mean: 17.2 Gy). Tumor absorbed doses ranged from 40.1 to 494.8 Gy (mean: 121.5 Gy). None of the patients had clinical venoocclusive disease or therapy-induced liver failure. Seven patients (17.5 %) had transient and 7 patients (17.5 %) had persistent LFT abnormalities. There were 27 (67.5%) responders (complete response, partial response, and stable disease). Tumor response correlated with higher tumor flow ratio as measured by Tc-99m MAA imaging.

CONCLUSION

Doses up to 99.5 Gy to uninvolved liver are tolerated with no clinical venoocclusive disease or liver failure. The lowest tumor dose producing a detectable response is 40.1 Gy. The utilization of MAA-based imaging techniques to determine tumor and liver blood flow for clinical treatment planning and the calculation of administered activity may improve clinical outcomes.

Resin 90Y-microsphere brachytherapy for unresectable colorectal liver metastases: modern USA experience

PURPOSE

Salvage therapy for patients with unresectable colorectal liver metastases that were refractory to oxaliplatin and irinotecan was performed via radioactive microspheres. High doses of radiation were delivered to tumors from permanently implanted 90Y microspheres, delivered through the hepatic arterial vessels.

METHODS AND MATERIALS

Patients from 7 institutions were selected for treatment after screening-defined vascular access to all the tumors, and imaging-confirmed microspheres would be implanted only in the liver tumors. All patients were followed with laboratory and imaging studies at regular intervals until death. Toxicities, both acute and late, were recorded, and actuarial survival determined.

RESULTS

A total of 208 patients were treated from April 2002 to April 2005. Median follow-up of the 129 men and 79 women is 13 months (range, 1-42 months). Median survival is 10.5 months for responders but only 4.5 months in nonresponders. No treatment-related procedure deaths or radiation-related venoocclusive liver failures were found. Computed tomography partial response was 35%; positron emission tomography response of 91% and reduction in carcinoembryonic antigen of 70% were achieved.

CONCLUSIONS

In this group of heavily pretreated patients, radioactive microspheres produced an encouraging median survival, with acceptable toxicity, and a significant objective response rate, which suggests that further investigation of this approach is warranted.

Yttrium-90 internal radiation therapy for hepatic malignancy

Surgical resection is the only potentially curative strategy in the treatment of patients with hepatic malignancy. Unfortunately, due to advanced stage, underlying liver disease, or medical comorbidities, most patients are inoperable at the time of presentation. As a result, various locoregional therapies have emerged for otherwise unresectable hepatic tumors. One such modality is Yttrium-90 (Y(90)) internal radiation therapy. Numerous studies demonstrate the safety and potential survival benefit of intra-arterial Y(90) for primary and metastatic liver tumors. However, more data is needed in order to understand the exact role of Y(90) in the algorithm of hepatic tumor management. This review presents the available literature on Y(90) with the aim of defining the current status of Y(90) in the armamentarium of therapeutic strategies for hepatic malignancy.

Pathologic response and microdosimetry of (90)Y microspheres in man: review of four explanted whole livers

INTRODUCTION

Radioactive microsphere (90)Y therapy is increasingly used for primary and metastatic solid tumors in the liver. We present an analysis of 4 explanted livers previously treated with (90)Y microsphere agents (glass or resin). One tumor nodule was analyzed with submillimeter three-dimensional microdosimetry.

METHODS AND MATERIALS

Four patients received hepatic artery delivery of (90)Y microspheres for unresectable hepatocellular and colon cancers. Whole livers were explanted as part of lifesaving cadaveric transplant in 2 patients with hepatoma. These patients had received glass microspheres as a procedural bridge to transplant. Autopsy was performed on 2 patients with colon cancer who died of progressive metastatic disease and who had been treated with resin microspheres. Complete pathologic review was performed on each whole liver, including estimation of the response of the tumor to therapy, distribution of microspheres in the tumor and normal liver tissues, and normal-tissue radiation response. A biopsy taken from the edge of a tumor nodule was sectioned serially for three-dimensional radiation dosimetry analyses. Three-dimensional microsphere coordinates within the biopsy specimen were used to calculate dosage using a three-dimensional dose kernel. Isodose coverage of tumor and normal liver areas and total dose delivered were determined.

RESULTS

Preferential and heterogeneous deposition of microspheres was noted at the edge of tumor nodules compared with the center portion of the tumor or normal liver parenchyma. Both glass and resin microspheres delivered high cumulative doses to the tumor, which varied from 100 Gy to more than 3000 Gy. No veno-occlusive disease or widespread radiation hepatitis was seen.

CONCLUSION

Microsphere ((90)Y) therapy delivers high numbers of spheres with resulting high total doses of radiation, preferentially in the periphery of tumors. Normal liver parenchyma showed little radiation effect away from the tumors. Heterogeneous high-dose regions in the tumor were produced by both glass and resin microspheres.

Analysis of the distribution of intra-arterial microspheres in human liver following hepatic yttrium-90 microsphere therapy

The microscopic distribution of microspheres in human liver following hepatic infusion of 32 microm diameter resin microspheres labelled with 90Y as treatment for an 80 millimetre diameter liver cancer has been investigated. Microspheres were found to deposit inhomogeneously in tissues, preferentially lodging in a region approximately 6 mm wide around the periphery of the tumour. A relative concentration of microspheres of 50 to 70 times that of normal hepatic parenchyma and 65 to 94 times that in the tumour centre was measured in this region. The deposition of spheres in the tumour periphery was not uniform, and cluster analysis showed that the spheres could be classified into clusters. The number of microspheres in a cluster was skewed towards low numbers and cluster sizes varied from 20 to 1500 microm. The observed deposition patterns indicate that the vascular tumour periphery will receive much greater radiation doses from radioactive microspheres than both normal tissue and the avascular tumour centre.

Tumour-to-normal uptake ratio of 90Y microspheres in hepatic cancer assessed with 99Tcm macroaggregated albumin

The selective delivery of a high dose of radiation to malignant hepatic tumours by infusion of non-biodegradable yttrium-90 (90Y) microspheres via the hepatic artery while sparing the non-tumorous liver parenchyma depends on the tumour-to-normal uptake ratio (T/N) of the therapeutic radiopharmaceutical. Using intrahepatic arterial technetium-99m macroaggregated albumin (99Tcm-MAA), the effect of tumour type, tumour vascularity assessed by hepatic angiography (HAG), tumour size and the degree of extrahepatic shunting on the T/N was investigated in 377 patients with hepatocellular carcinoma (HCC) and 25 patients with colorectal liver metastases. HCC was shown to have a wider range of T/N (0.2-26.5) compared with liver metastases (2.3-7.2). HCC with vascularity grade 1 on HAG had significantly lower T/N but there was no significant difference in HCC with higher vascularity grades. This confirmed that vascularity on HAG does not predict T/N. Overall there was no correlation between T/N and tumour size. Large tumours (> 20 cm) had a significantly lower T/N, probably due to necrosis in the tumour centres. A decrease in mean T/N with increasing percentages of lung shunting was observed in HCC. Determination of T/N by simulation with 99Tcm-MAA is recommended before internal radiation therapy with 90Y microspheres.

Clinical evaluation of the partition model for estimating radiation doses from yttrium-90 microspheres in the treatment of hepatic cancer

Radiation doses to the tumour and non-tumorous liver compartments from yttrium-90 microspheres in the treatment of hepatic cancer, as estimated by a partition model, have been verified by correlation with the actual doses measured with a beta probe at open surgery. The validity of the doses to the lungs, the tumour and non-tumorous liver compartment as estimated by the partition model was further evaluated in clinical settings. On the basis of the observation that one of three patients who received more than 30 Gy from a single treatment and one of two patients who received more than 50 Gy from multiple treatments developed radiation pneumonitis, it was deduced that an estimated lung dose < 30 Gy from a single treatment and a cumulative lung dose < 50 Gy from multiple treatments were probably the tolerance limits of the lungs. Three of five patients who received lung doses > 30 Gy as estimated by the partition model and were predicted to develop radiation pneumonitis, did so despite the use of partial hepatic embolization to reduce the degree of lung shunting. Furthermore, a higher radiological response rate and prolonged survival were found in the group of patients who received higher tumour doses, as estimated by the partition model, than in the group with lower estimated tumour doses. Thus the radiation doses estimated by the partition model can be used to predict (a) complication rate, (b) response rate and (c) duration of survival in the same manner as the actual radiation doses measured with a beta probe at open surgery. The partition model has made selective internal radiation therapy using 90Y microspheres safe and repeatable without laparotomy.

Partition model for estimating radiation doses from yttrium-90 microspheres in treating hepatic tumours

A uniform distribution of yttrium-90 (90Y) microspheres throughout the entire liver has always been assumed for dose calculation in treating hepatic tumours. A simple mathematical model was formulated which allows estimation of the activities of a therapeutic dose of 90Y microspheres partitioned between the lungs, the tumour and the normal liver, and hence the radiation doses to them. The doses to the tumour and normal liver were verified by intra-operative direct beta-probing. The percentage of activity shunted to the lung and the tumour-to-normal tissue ratio (T/N) were obtained from gamma scintigraphy using technetium-99m-labelled macroaggregated albumin (MAA) which simulates the 90Y microspheres used in subsequent treatment. The intrahepatic activity was partitioned between the tumour and the normal liver based on the T/N and their masses determined from computerized tomography slices. The corresponding radiation doses were computed using the MIRD formula. The estimated radiation doses were correlated with the doses directly measured using a calibrated beta-probe at laparotomy by linear regression. The radiation doses to the tumour and the normal liver, estimated using the partition model, were close to that measured directly with coefficients of correlation for linear regression: 0.862 for the tumours and 0.804 for the normal liver compartment (P<0.001). The partition model permits a distinction between the radiation doses received by the tumour and the normal liver to be made and the doses thus estimated are close to the actual doses received. The optimal doses to the tumour and normal liver and hence the required quantity of 90Y microspheres to be administered can be easily predetermined.

Diagnostic angioscintigraphic evaluation of malignant hepatic tumors before catheter embolization: determination of shunt, flow distribution, and reflux

PURPOSE

The aim of this study was to evaluate quantitatively arteriovenous shunts in malignant liver tumors by injection of 99mTc macroaggregates of albumin (MAA) into the tumor-feeding artery after selective catheterization.

METHODS

In 40 patients with malignant liver tumors (33 hepatocellular carcinomas and 7 metastases of colorectal cancer), a mean dose of 200 MBq 99mTC MAA was injected arterially during angiography. The embolized area and the lungs were then visualized using a gamma camera. A dedicated computer program calculated pulmonary shunt rates.

RESULTS

The majority of patients (n = 30) with hepatocellular carcinoma showed small shunts varying from 0 to 15%; only 3 of these patients had shunts ranging from 18% to 37%. In patients with colorectal carcinoma metastases (n = 7) the shunt varied from 0 to 3% (2 +/- 1%), probably due to a physiological shunt in normal liver tissue in the embolized area. Importantly, the degree of shunt found bore no correlation to the tumor volume or to the pattern of vascularity on angiography.

CONCLUSION

Diagnostic angioscintigraphy is a useful tool for pretherapeutic evaluation of the capacity of an individual tumor to retain particles and to measure extratumoral shunting; these are essential for therapy planning, as they can help to increase the safety and effectiveness of embolization.

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.

An experimental study and clinical pilot trials on yttrium-90 glass microspheres through the hepatic artery for treatment of primary liver cancer

BACKGROUND

Yttrium-90 (90-Y) glass microsphere is a new kind of radiation microsphere for internal radiation therapy of primary liver cancer (PLC). The study was carried out by administration of 35 microns nondegradable 90-Y glass microsphere through the hepatic artery for treatment of PLC.

METHODS

Six rabbits were injected with 185-1480 megabecquerels (MBq) of 90-Y glass microspheres, and three rabbits were injected with 35-300 mg of 89-Y glass microspheres for the toxic test. Eighteen patients received 2442-5550 MBq of 90-Y glass microspheres for the treatment of PLC. Whole blood counts, liver function, and imaging examination were performed. Pathologic examinations were performed on all rabbits.

RESULTS

All rabbits were apparently well after absorbing 114.1-845.2 Gy 90-Y glass microspheres in the liver but showed transient degeneration of hepatocytes and portal fibrosis histologically. The mean absorbed dose in liver tissue of patients with PLC was 30.33 Gy, whereas that in tumor tissue was 88 Gy and the highest in tumor tissue, 186.36 Gy. The mean tumor:liver tissue ratio was 3:1; the highest, 14:1. Fourteen patients were still alive after half a year's follow-up and 6 of these 14 were still alive after 1 year.

CONCLUSIONS

The rabbits could tolerate up to eight-fold of the upper limit of clinical dose (100 Gy). Good responses to the radiation therapy of 90-Y glass microspheres in patients with localized and hypervascular or vascular mass were achieved. Contraindications for the therapy were presence of massive hepatic arterioportal shunt and cancer emboli in the main portal vein. It is safe and applicable to deliver 90-Y glass microspheres in large doses through the hepatic artery for internal radiation treatment of PLC.

Combined hepatic artery 5-fluorouracil and irradiation of liver metastases. A randomized study

The effect of hepatic irradiation (RT) after intraarterial 5-fluorouracil (5-FU) was evaluated in 37 randomized patients with colorectal adenocarcinoma hepatic metastases. Patients underwent percutaneous transbrachial artery catheterization of the hepatic artery followed by 21-day continuous 5-FU infusion (CT). Hepatic irradiation of 25.5 Gy was delivered to 19 patients 14 days after completion of infusion (CT + RT). All patients received subsequent weekly maintenance 5-FU. A 37% (seven of 19) response rate was observed in CT + RT, and a 50% response rate (nine of 18) in CT: median survival was 6 months for CT + RT, and 8 months for CT, (P = 0.106). Improved survival was observed in two subsets of patients. Tumor vascularity was graded angiographically from 0 to 4+; those patients with highest vascularity (4+) had a 20-month median survival (P = 0.0009). Patients with Grade 1, well-differentiated, histologic type had a median survival of 20 months (P = 0.0001). Four patients with both 4+ vascularity and Grade 1 histologic type had 27.5 months' median survival (P = 0.0019). Age, performance status, elevated liver function tests, previous systemic therapy, and time interval between diagnosis and entry on this study did not impact on survival (P greater than 0.05), nor did these variables eliminate the significance of vascularity and grade (P less than 0.05). Survival after intraarterial 5-FU infusion was not improved by this regimen of sequential external irradiation. Regional therapy may benefit those patients with 4+ vascular tumors and/or well-differentiated tumor grade. Future trials are needed to explore the interaction of halogenated pyrimidines with irradiation and determine whether these prognostic factors can aid in patient selection for regional therapy of hepatic metastases.

Regional treatment of hepatic metastases and hepatocellular carcinoma

Hepatic metastases represent a common site of dissemination for a number of primary malignancies related in part to the dual blood supply, large blood flow, and receptive environment of the hepatic parenchyma. Although this review focuses on regional therapy, we have included sections on systemic therapy to better interpret the results with intrahepatic therapy. We will also discuss the efficiency of hepatic arterial ligation, embolization, and radiotherapy of hepatic metastases. Primary gastrointestinal neoplasms are particularly prone to produce hepatic metastases. Because colorectal carcinoma metastasizes to the liver in up to 70% of patients with advanced disease, the treatment of hepatic metastases is a relevant topic. We will discuss the systemic and regional therapy of colorectal, gastric, and gallbladder cancers. Breast carcinoma and malignant melanoma frequently metastasize to the liver, and we have described systemic and regional treatments of these diseases. Because sarcomas are often treated by regional therapy, we have included a section on the treatment of hepatic sarcomas. Neuroendocrine tumors (carcinoid and islet cell), although often slow growing, frequently metastasize to the liver and then cause symptomatic problems. Much of the work done with embolization and hepatic ligation in the treatment of hepatic metastases has been performed in neuroendocrine tumors, and these studies, as well as the systemic and regional chemotherapy of hepatic metastases, will be described. The last section concerns the treatment of hepatocellular carcinoma. We have outlined the staging systems used. We then detail the results of systemic and intrahepatic therapy, embolization, and hepatic ligation in the treatment of hepatocellular carcinoma. Because hepatic metastases are a frequent problem, many patients are available for clinical investigation. It is hoped that newer strategies for the treatment of liver metastases will lead to higher response rates and perhaps control of local disease. These therapeutic approaches may also give us leads to the treatment of systemic disease.

Hepatic irradiation in primary and metastatic liver cancer

Between December 1973 and September 1987, 21 patients with primary liver cancer and 41 patients with metastatic liver cancer were treated with external irradiation, intra-arterial infusion chemotherapy and/or transarterial embolization (TAE) at the National Medical Center Hospital, the National South Kyushu Central Hospital and the National Kure Hospital. Of the patients with primary liver cancer, 13 cases were treated with intra-arterial infusion chemotherapy (30-40 mg adriamycin or 10 mg mitomycin C) and hepatic irradiation. Eight cases were treated by TAE and hepatic irradiation. In the Child A group, the survival period of the chemotherapy + hepatic irradiation cases (mean: 608 days) was longer than that of the TAE + hepatic irradiation cases (mean: 216 days). The median survival period of all the cases was 7.0 months (mean: 10.9 months). For 16 of the 21 patients (who had absorbed over 40 Gy), the median survival period was 11.9 months (mean: 11.7 months). For 5 of the 21 patients (who had absorbed below 40 Gy), the median survival period was 4.3 months (mean: 7.9 months). Of the patients with metastatic liver cancer, the median survival period was 7.2 months (mean: 8.0 months). For 22 of the 41 patients (who had absorbed over 40 Gy), the median survival was 7.9 months (mean: 12.6 months). For 19 of the 41 patients (who had absorbed below 40 Gy), the median survival period was 1.7 months (mean: 2.6 months). The pretreatment serum GOT (glutamate oxaloacetate transaminase) levels and the pretreatment Karnofsky performance status index were the factors governing the prognosis of the cases with metastatic liver cancer, while toxicity was generally mild.

Effects of hepatic arterial yttrium 90 glass microspheres in dogs

A 22-micron glass microsphere called TheraSphere (Theragenics Corp., Atlanta, GA) has been developed in which yttrium 89 oxide is incorporated into the glass matrix and is activated by neutron bombardment to form the beta-emitting isotope yttrium 90 (Y 90) before using the spheres as radiotherapeutic vehicles. The injection of up to 12 times (on a liver weight basis) the anticipated human dose of nonradioactive TheraSphere into the hepatic arteries of dogs was well tolerated and produced clinically silent alterations within centrolobular areas. The hepatic arterial (HA) injection of radioactive TheraSphere also produced portal changes similar to those observed in humans after external beam therapy. While the extent of damage increased with the delivered dose, radiation exposures in excess of 30,000 cGy did not cause total hepatic necrosis and were compatible with survival. No microspheres distributed to the bone marrow and absolutely no myelosuppression was encountered in any animal. Proposed hepatic exposures to humans of 5000 to 10,000 cGy by means of these microspheres, therefore, would appear to be feasible and tolerable. Radiotherapeutic microsphere administration preceded by regional infusion of a radiosensitizing agent and/or immediately following the redistribution of blood flow toward intrahepatic tumor by vasoactive agents can potentially yield a synergistic, highly selective attack on tumors confined to the liver.

Therapeutic use of 90Y microspheres

Glass microspheres 20-30 microns in diameter containing either 31P or 89Y that can be activated by neutron bombardment to 32P or 90Y respectively, have been produced for intra-arterial radiotherapy of liver tumors. The spheres are insoluble in body fluids, non-toxic, and can concentrate in liver tumors of animals by direct injection into the hepatic artery. This gives a higher radiation dose to the tumor than can be achieved with external beam therapy. Trials in rabbits and dogs have proven successful and this product (90Y TheraSpheres) is now entering limited human clinical trials.

Hepatic artery catheterization via the superior pancreaticoduodenal artery

The superior pancreaticoduodenal artery is a continuation of the gastroduodenal artery. Besides being a good-sized artery, it is easily accessible. It is a reasonable vascular access for hepatic artery cannulation.

A method for the selective beta-irradiation of individual lymphocyte microcultures and its application in a preliminary study of radiation sensitivity

A method that permits high energy beta-irradiation to be applied to individual lymphocyte microplate cultures is described. The principle involves the introduction of single energy sources (in this case 32P) contained within tubes which rest inside wells containing the lymphocyte cultures. Cell viability and mitogen-induced transformation were studied under these conditions. Dose-response effects were clearly demonstrated. The method is simple and, provided the precautions described are adhered to, safe. It should be applicable to studies of radiation sensitivity of putative target cells in various clinical situations.

Hepatic metastases--a physiological approach to treatment

Hepatic metastases derived from primary malignancy of the gastrointestinal tract have a grave prognosis, with median survival rates varying from 3 to 11 months. Surgery for isolated metastases and intrahepatic artery chemotherapy are the most effective treatment options currently available. We have explored the potential use of radioactive microspheres delivered into the liver by the hepatic artery as a form of internally irradiating metastatic liver cancer. Microspheres containing radioactive Yttrium injected into the hepatic artery concentrate in the metastases rather than normal liver parenchyma, due to the fact that the blood supply of metastases is derived preferentially from the hepatic artery. Using a rabbit tumour model, radioactive microspheres delivered into the hepatic artery have been shown to lodge preferentially in tumour tissue. The therapeutic application of this phenomenon is that metastases may receive many times the radiation dose delivered to normal liver parenchyma when radioactive microspheres are delivered into the hepatic artery. This would mean that a mean dose of 30 Gy delivered to normal liver tissue would result in greater than 150 Gy being delivered to tumour tissue. Current results in experiments suggest that this form of treatment may have considerable potential for prolonging survival of patients with hepatic metastases.