Conversion by new treatment modalities of nonresectable to resectable hepatocellular cancer

Successful conversion therapy for unresectable hepatocellular carcinoma is getting closer: A systematic review and meta-analysis

Background

Conversion therapy provides selected patients with unresectable hepatocellular carcinoma the opportunity to undergo a curative hepatectomy and achieve long-term survival. Although various regimens have been used for conversion therapy, their conversion rate and safety remain uncertain. Therefore, we conducted some meta-analyses to evaluate the efficacy and safety of several conversion regimens in order to elucidate the optimal regimen.

Method

We performed systematic literature research on PubMed, Embase, and the Web of Science until July 30, 2022. Chemotherapy, transcatheter arterial chemoembolization (TACE), molecular therapy (targeted therapy, immunotherapy, or a combination of both), and combined locoregional-systemic therapy were the conversion regimens we targeted.

Results

Twenty-four studies were included. The pooled conversion rates for chemotherapy, TACE, molecular therapy, and combined locoregional-systemic therapy were 13% (95% confidence interval [CI], 7%-20%; I² = 82%), 12% (95% CI, 9%-15%; I² = 60%), 10% (95% CI, 3%-20%; I² = 90%), and 25% (95% CI, 13%-38%; I² = 89%), respectively. The pooled objective response rates (ORR) for chemotherapy, TACE, molecular therapy, and combined locoregional-systemic therapy were 19% (95% CI, 12%-28%; I² = 77%), 32% (95% CI, 15%-51%; I² = 88%), 30% (95% CI, 15%-46%; I² = 93%), and 60% (95% CI, 41%-77%; I² = 91%), respectively. The pooled grade ≥3 AEs for chemotherapy, TACE, molecular therapy, and combined locoregional-systemic therapy were 67% (95% CI, 55%-78%; I² = 79%), 34% (95% CI, 8%-66%; I²= 92%), 30% (95% CI, 18%-43%; I² = 84%), and 40% (95% CI, 23%-58%; I² = 89%), respectively. Subgroup analyses showed the conversion rate, ORR and grade ≥3 AE rate for tyrosine kinase inhibitor (TKI) combined with immune checkpoint inhibitor (ICI) and locoregional therapy (LRT) were 33% (95% CI, 17%-52%; I² = 89%), 73% (95% CI, 51%-91%; I² = 90%), 31% (95% CI, 10%-57%; I² = 89%), respectively.

Conclusion

Combined locoregional-systemic therapy, especially TKI combined with ICI and LRT, may be the most effective conversion therapy regimen, associated with a significant ORR, conversion potential, and an acceptable safety profile.

Phase II trial of nolatrexed dihydrochloride [ThymitaqTM, AG 337] in patients with advanced hepatocellular carcinoma

BACKGROUND

To evaluate the tolerability and efficacy of nolatrexed in patients with advanced hepatocellular carcinoma.

PATIENTS AND METHODS

Forty-eight patients were entered onto this study. Nolatrexed was administered every 3 weeks as a 24-h continuous intravenous infusion of 725 mg/m(2)/day for 5 days. Doses were adjusted to maintain a dose level that produced > or = grade 2 toxicity. Response was assessed after every two cycles. Plasma pharmacokinetic samples were assayed using a validated high performance liquid chromatography ultraviolet method.

RESULTS

Thirty-nine (81%) patients were evaluable for response. The mean number of cycles received was 2.8 (range 1-12). The mean dose intensity was 700 mg/m(2)/day (SD of 71). One patient had a partial response (2.6%) for 7 months. Eighteen (46%) patients had SD, 20 (51%) patients had progressive disease. The median duration of SD was 93 days. The median overall survival was 32 weeks [95% CI (22-37)]. The most frequent Grade 3 or 4 adverse events were stomatitis (25%), dehydration (23%) and asthenia (21%). There was no evidence of cumulative toxicity. The overall median plasma concentration (C (max)) was 14.20 microg/mL (range 1.41 to 119 microg /mL) with no accumulation observed between cycles 1-6.

CONCLUSION

This phase II study of nolatrexed in advanced HCC patients, demonstrated minimal activity and significant stomatitis. Hence, it does not warrant further study as a single agent for this disease.

Non-surgical treatment of hepatocellular carcinoma

Primary hepatocellular cancer is a disease with a poor prognosis for which there is little consensus on treatment and a paucity of comparative trials. The coexistence of cancer with cirrhosis complicates treatment, and also confers a high risk for the development of further tumours. Surgery, either by hepatic resection or orthotopic liver transplantation, is only a feasible option in a minority of patients. This article surveys the non-surgical approaches to the treatment of hepatocellular cancers-local ablation techniques, arterial embolization with and without chemotherapy, conventional chemotherapy and hormonal modulation, and targeted and external irradiation.

Surgery after downstaging of unresectable hepatic tumors with intra-arterial chemotherapy

BACKGROUND

This retrospective study was performed to assess the outcome among patients who underwent hepatic resection or tumor ablation after hepatic artery infusion (HAI) therapy down-staged previously unresectable hepatocellular carcinoma (HCC) or liver metastases from colorectal cancer (CRC).

METHODS

Between 1983 and 1998, 25 patients with HCC and 383 patients with hepatic CRC metastases were treated with HAI therapy for unresectable liver disease. We retrospectively reviewed the records of 26 (6%) of these patients who underwent subsequent surgical exploration for tumor resection or ablation.

RESULTS

At a median of 9 months (range 7-12 months) after HAI treatment, four patients (16%) with HCC underwent exploratory surgery; two underwent resection with negative margins, and the other two were given radiofrequency ablation (RFA) because of underlying cirrhosis. At a median postoperative follow-up of 16 months (range 6-48 months), all four patients were alive with no evidence of disease. At a median of 14.5 months (range 8-24 months) after HAI therapy, 22 patients with hepatic CRC metastases underwent exploratory surgery; 10 underwent resection, 6 underwent resection and RFA or cryotherapy, and 2 underwent RFA only. At a median follow-up of 17 months, 15 (83%) of the 18 patients with CRC who had received surgical treatment had developed recurrent disease; the other 3 died of other causes (1 of postoperative complications) within 7 months of the surgery. One patient in whom disease recurred underwent a second resection and was disease-free at 1 year follow-up.

CONCLUSIONS

Hepatic resection or ablation after tumor downstaging with HAI therapy is a viable option for patients with unresectable HCC. However, given the high rate of recurrence of metastases from CRC, hepatic resection or ablation after downstaging with HAI should be used with caution.

Primary and metastatic liver cancer

OBJECTIVES

To review liver physiology, the disease process, diagnostic tests, and current treatment options for primary and metastatic liver cancer.

DATA SOURCES

Research studies, review articles, and textbooks relating to liver cancer.

CONCLUSIONS

Surgical resection offers the best available treatment modality, but only a small percentage of patients are eligible. However, combined treatment of radiation therapy and chemotherapy (systemic and intra-arterial), as well as chemoembolization, cryosurgery, and transplantation, offers hope of palliation, conversion of unresectable to resectable disease, and prolonged survival.

IMPLICATIONS FOR NURSING PRACTICE

Understanding and knowledge of the disease process and treatment modalities for primary and metastatic liver cancer will assist the oncology nurse in educating patients and families during their diagnostic and treatment phases.

Influence of prognostic groupings and treatment results in the management of unresectable hepatoma: experience with Cisplatinum-based chemoradiotherapy in 76 patients

PURPOSE

Internationally, hepatoma is a common cause of cancer death. Although the only curative therapy is surgical, most tumors are unresectable and cause death. The value of nonsurgical, antineoplastic therapy for such tumors is controversial. This study was undertaken to extend and confirm promising, but preliminary, treatment observations in the unresectable context.

METHODS AND MATERIALS

From 1988 to 1993, 76 patients with unresectable, biopsy proven, hepatoma underwent uniform pretreatment assessment followed by induction therapy with external beam radiotherapy (21 Gy/7 fractions/10 days) and intravenous Cisplatinum, 50 mg/m2. One month later patients began monthly intrahepatic artery Cisplatinum, 50 mg/m2. Clinical course and treatment outcomes were correlated with previously published prognostic factors and groupings (Nomura et al., Okuda et al., Stillwagon, et al.).

RESULTS

The toxicity of this therapy was modest and nonlimiting. Twenty-four patients (32%) progressed during induction and prior to receiving two cycles of intrahepatic artery Cisplatinum without evidence of benefit. Patients showing this early progression were more likely to be Stillwagon unfavorable than favorable (p = 0.013), Okuda Stage II than Stage I (p = 0.024), and slightly but not statistically more likely to be alpha-fetoprotein positive than alpha-fetoprotein negative (p = 0.098). The overall objective response rate was 43% (38% among AFP positive and 62% among AFP negative patients) (p = 0.15). Although 21 patients had evidence of extra hepatic metastases, survival for these patients did not differ from patients without metastases (p = 0.09) and patients with extra hepatic metastases were just as likely to show intrahepatic response (p = 0.84).

CONCLUSION

The chemoradiotherapy program utilized produced objective response and minimal toxicity. One-third of patients progressed rapidly in spite of treatment. Among the remaining patients, response occurred frequently. This treatment appears to represent an important therapeutic option for many, but not all, patients with unresectable hepatoma.

Cytoreduction and sequential resection for surgically verified unresectable hepatocellular carcinoma: evaluation with analysis of 72 patients

The poor prognosis of hepatocellular carcinoma (HCC) was partly a result of the majority of unresectable HCCs in clinical patients. Fortunately, with the progress of regional cancer therapies and multimodality treatment, some of the localized unresectable HCCs were converted to resectable ones. During the period 1960-1994, 72 of the 663 patients with surgically verified unresectable HCCs have been converted to resectable. Successful cytoreduction with median diameter reduced from 10 cm to 5 cm was mainly a result of the triple or double combination treatment with hepatic artery ligation, hepatic artery cannulation with infusion, radioimmunotherapy, and fractionated regional radiotherapy. The interval between the first operation and the sequential resection was 5 months. The operative mortality was 1.4% for sequential resection, and the 5-year survival was 62.1%. Analysis of factor influencing sequential resection rate revealed HCCs that were single nodule, well encapsulated, situated at right lobe or hepatic hilum, associated with micronodular cirrhosis, and treated with triple or double combination modalities had higher sequential resection rate as compared to their counterparts. Analysis of factors influencing survival after sequential resection revealed that HCCs with a solitary tumor confined in one lobe, without tumor embolus, and without residual cancer in specimen of sequential resection, had longer survival. It is suggested that localized unresectable, solitary, well encapsulated, right lobe or hilar HCC, associated with micronodular cirrhosis, will be good candidates for cytoreduction and sequential resection; and HCCs with unilateral involvement, without tumor embolus, and with complete necrosis of tumor after multimodality treatment favored better prognosis.

Conversion of unresectable to resectable liver cancer: an approach and follow-up study

In the last decade, significant improvement has been achieved in the treatment of hepatocellular cancer by combining therapies from different disciplines, and using effective biologic response modifiers to improve response to existing therapy. While operative resection remains the only curative modality, a select group of patients with unresectable fibrolamellar or nodular variant, can be converted from unresectable status to resectable by combining chemotherapy and radiotherapy. We reviewed the recent experience with intra-arterial chemotherapies and use of external beam radiotherapy and isotopic immunoglobulin-directed radiotherapy in the treatment of unresectable hepatocellular cancer. While significant tumor response can be achieved with these therapies they are short-lived, and long-term survival is poor. When combined with operative resection, however, a significant survival advantage is achieved. The expected survival of the unresectable patient is then altered from 18 to 24 months for chemotherapy or radiation alone, or when used in combination, to 44 months for patients converted to resectable status. We conclude that the need for more effective chemotherapy is imperative, and the major role for chemotherapy or radiotherapy in hepatocellular cancer is to convert an unresectable patient to resectable status.

Model based calculation for effective cancer radioimmunotherapy

The major problem of tumour radioimmunotherapy remains the low tumour antibody uptake and this leads to inadequate tumour irradiation. The antibody characteristics which influence uptake have been identified and quantified previously using a non-linear compartmental model that simulates antibody distribution to tumour and body after intravenous injection. The model has now been extended, in combination with MIRD dosimetry tables, to calculate the integral tumour/body radiation dose for a range of antibody masses (1, 10 and 50 mg), sizes (binding site fragments and whole molecules) and affinities (K = 10(9)-10(13) mol-1). Antibody requirements for delivering 60 Gy to the tumour over 11.6 days were calculated for 131I and 90Y-labelled antibodies and included the effect of widely varying dose rates. The model predicted that intact antibodies of high affinity (10(11)-10(13) mol-1) produced effective tumour radiation doses with acceptable whole body radiation levels. By contrast, antibody fragments gave higher body radiation levels and required larger injected activity because of renal excretion. The model predicted higher therapeutic indices for 90Y-labelled antibody compared with 131I.

Treatment of unresectable primary liver cancer: with reference to cytoreduction and sequential resection

Unquestionably, progress has been made in the early detection and early treatment of primary liver cancers (PLCs), although most remain unresectable, mainly because the cancer is advanced and coexists with liver cirrhosis, particularly in Oriental patients. Thanks to the progress of regional cancer therapy, a multidisciplinary approach, and changing concepts about surgical oncology, it has been proved that some unresectable but not far advanced PLCs are potentially convertible to being resectable, particularly those cancers confined to the right lobe of a cirrhotic liver. A retrospective analysis of 571 unresectable PLCs revealed the following: (1) There was an increase in 5-year survivals in the series, from 0% during the 1960s (n = 61), to 4.8% during the 1970s (n = 163), to 21.2% during the 1980s (n = 347). It might be a result of the increase in double- or triple-modality treatments in these series (from 9.8%, to 19.6%, to 70.3%, respectively) and in the sequential resection rate after cytoreduction (from 0%, to 2.5%, to 14.7%). (2) The combination of hepatic artery ligation, hepatic artery cannulation and infusion, and intrahepatic arterial radioimmunotherapy has resulted in better shrinkage of the tumor, a higher sequential resection rate, and a higher 5-year survival (28.2%). (3) Of the 55 patients who had initially unresectable PLCs and yielded "cytoreduction and sequential resection," the 5-year survival was 58.5%. It is concluded that cytoreduction and sequential resection might be an important approach to improving the prognosis of patients with unresectable PLCs.

Iodized oil in the treatment of hepatocellular carcinoma

When injected into the hepatic artery the contrast agent Lipiodol (iodized poppy seed oil) is selectively retained by hepatocellular carcinoma (HCC) for a prolonged period of time. Liver computed tomography (CT) performed after Lipiodol angiography is more sensitive than ordinary CT at imaging HCC. Arterial administration of cytotoxic drugs and radioisotopes conjugated to Lipiodol has been shown to be reasonably safe in patients with irresectable HCC. These therapies, often combined with embolization, provide effective palliation, better tumour response and improved survival compared with other available treatments. Their use as a preoperative adjunct to surgical resection of HCC is controversial.

Management options for primary hepatocellular carcinoma. An overview

Hepatocellular carcinoma (HCC) is the seventh most common cancer in men and the ninth most common cancer in women with 500,000 to 1,000,000 new cases per year. Several risk factors (sex hormones, alcohol, thorotrast, aflatoxin B1, hepatitis B or C, haemochromatosis, alpha 1-antitrypsin deficiency, tyrosinemia, porphyria cutanea tarda, acute intermittent porphyria, Wilson's disease) associated with the development of HCC have been identified from epidemiological studies. The diagnosis is usually based on a combination of clinical and laboratory findings together with radiographic and histopathologic characteristics. HCC remains difficult to treat with a median survival of 3 to 6 months after the onset of symptoms. Surgical resection is the mainstay of treatment for HCC. Transcatheter arterial embolization and percutaneous ethanol injection have been used but neither therapy has been evaluated in a prospective randomized study. Combination treatment (e.g. chemotherapy and resection) may be of value but randomized controlled trials with long-term follow-up are still needed. Liver transplantation should be reserved for carefully selected patients.

Monoclonal antibodies in cancer detection and therapy

Anticancer antibodies have had a long history in the management of cancer, with major applications having been shown in the immunohistochemistry and immunoassay of tumor-associated antigen markers. With the advent of hybridoma-derived monoclonal antibodies, attempts to use these more reproducible reagents in vivo for cancer detection and therapy have intensified. Radiolabeled monoclonal antibodies appear to be gaining a role in the management of cancer by means of imaging methods to detect sites of increased radioactivity, and several products have been developed and tested clinically. In the area of radioimmunotherapy, a number of problems still need to be solved, including low tumor uptake of the radioimmunoconjugate, dose-limiting myelotoxicity, and the induction of an immune response to repeated doses of murine (foreign) immunoglobulins. Similar problems exist for toxin and drug immunoconjugates, but these also fail to benefit from the "bystander" effect of the ionizing radiation delivered with radioimmunoconjugates, and plant and bacterial toxin molecules appear to have additional immunogenicity that restricts repeated injections. Despite these limitations, recombinant engineering and other chemical approaches are making progress in developing second-generation immunoconjugates that may be more efficacious and less immunogenic as cancer-selective therapeutics. Although nonconjugated, "naked", murine monoclonal antibodies have shown limited success in the therapy of human neoplasms, human and "humanized" forms may be more effective, particularly in lymphatic tumors. Some evidence also suggests that anti-idiotype antibodies (antiantibodies) may serve as surrogate antigens in cancer vaccines. Thus, a number of promising immunologic approaches for cancer diagnosis, detection, and therapy have made important progress in recent years.

Improved survival for hepatocellular cancer with combination surgery and multimodality treatment

Forty-one hepatic resections for malignant hepatomas were done in 35 consecutive patients from August 1985 to 1990. Twenty-one patients presented initially with resectable lesions and underwent resection for curative intent. Fourteen patients initially presented with unresectable intrahepatic disease. These patients underwent combined radiation and chemotherapy. Radiation consisted of external beam in all patients and 131I-antiferritin in 10 patients. Greater than 50% tumor reduction was noted in all patients, and resection then was performed. Six patients recurred and were re-resected. Complications occurred in 15 patients (36%), with no difference between groups. There were no perioperative deaths. Five-year actuarial survival was 45% and 48% for resection and multimodality. The authors conclude that some patients with unresectable intrahepatic hepatoma may successfully be converted to resectable by multimodality radiation/chemotherapy. The survival of these patients is similar to that of primary resected patients. Further, multiple, sequential resections appear to significantly prolong survival and can be performed with an acceptable morbidity and mortality rates.

Non-surgical treatment of hepatocarcinoma

Hepatocellular carcinoma (HCC) is one of the most common tumors affecting man. It is the general feeling that only hepatectomy can give a chance for cure. However, less than 20% of patients can be resected, and other treatment modalities are required. Systemic (chemotherapy, hormonotherapy, immunotherapy) and loco-regional (intratumoral injection of alcohol, intra-arterial chemotherapy embolization, internal radiotherapy) approaches have been developed. In view of the small number of patients, tumor and patient heterogeneity, and difficulties in assessing tumor response, the real place of these treatments is difficult to evaluate. A review of the literature suggests that embolization with Gelfoam, even when given without chemotherapy, has an effect on response rate and on survival, and could be considered, at the present time, as the most attractive treatment in non-operable HCC. Chemotherapy seems effective only if combined with embolization. When administered alone by the systemic or the intra-arterial hepatic route, no clinically significant activity can be found. Unexpectedly, Lipiodol by itself seems inactive, and the co-administration of chemotherapy does not improve activity. Other approaches such as intratumoral injection of alcohol, immunotherapy, hormonotherapy, and radioimmunotherapy are still experimental, and well-designed studies are needed to identify their role.

Radioimmunotherapy: clinical results and dosimetric considerations

Radiolabeled antibodies for cancer therapy are being investigated in clinical trials in more than 30 centers. 131Iodine-labeled antibody (Ab) therapy of solid tumors has produced few responses when given alone. When given in conjunction with chemotherapy and external beam therapy in hepatoma patients, objective responses have occurred. Because of the short range of 131I, 90Y and 186Re are being studied and objective responses have occurred in patients without the addition of other therapies. 131I-labeled Ab therapy of lymphoma, a radioresponsive tumor, has produced a much higher objective response rate than in other solid tumors. Regional RIT has not been shown to offer a definite advantage over the intravenous route. Tumor doses have generally been less than 2000 cGy per treatment with some tumors receiving higher doses. The bone marrow is the dose-limiting organ for RIT and marrow cryopreservation with subsequent reinfusion may prove useful.

Liver transplantation for hepatocellular carcinoma: clinical results and future aspects

The treatment of unresectable hepatocellular carcinoma (HCC) by liver transplantation remains controversial. In our series, the 5-year survival value for 87 patients who underwent transplantations between 1972 and 1990 was 19.6%. There was no difference in the long-term survival of patients who had underlying cirrhosis and those who did not. In patients with early-stage tumors the long-term prognosis was improved, the 5-year survival in stage II disease being 55.6% according to UICC criteria. Even in some cases of more advanced tumour stage, good long-term results were obtained. In a review of the recent literature, we evaluated prognostic factors to work out criteria for a more differentiated indication for liver transplantation. Resection of increased radicality--which will keep its place as the therapy of choice--and transplantation should be performed complementarily. Further developments will reveal the value of multimodal therapeutic strategies, including chemo-embolisation, chemotherapy and immunotherapy.

Therapeutic aspects of radio-isotopes in hepatobiliary malignancy

Liver tumours frequently present at a late stage and only a minority of patients are likely to benefit from resection or transplantation. Inoperable tumours carry a grave prognosis. External beam irradiation of the liver is dose-limited by the radiosensitivity of hepatocytes, particularly in the presence of cirrhosis, but internal radiation using radio-isotope sources can achieve more selective irradiation of the chosen field. Sealed sources are dose-limited by their effects on surrounding tissues, whereas with unsealed sources the dose of radio-isotope administered is limited by bone marrow suppression. Iridium-192 wires are most frequently employed as a sealed intracavitary source. They may be inserted surgically, transhepatically or endoscopically. Doses of up to 60 Gy can be delivered to a malignant biliary stricture without damage to the surrounding parenchyma. The incidence of cholangitis is low if treatment is administered after insertion of an endoprosthesis. Unsealed radio-isotope sources may be injected directly into the tumour, administered embolically via the hepatic artery in the form of microspheres or lipid droplets, or given via parenteral infusion attached to tumour-specific antibodies. Of these vehicles, the lipid agent Lipiodol appears to be the most effective and can deliver a potentially lethal dose of radiation to small tumours. Host reaction to the injected antibody remains a major drawback to the use of monoclonal antibodies as targeting agents. Iodine-131 is a beta- and gamma-emitter, producing a local tumoricidal effect and allowing accurate dosimetry by means of external scintigraphy. Yttrium-90 is a pure beta-emitter with a greater maximum beta energy and cytotoxic range; however, it is retained in bony tissues, resulting in a dose-related risk of marrow suppression. Bone absorption cannot be measured by external imaging owing to the absence of gamma emission. This lack of accurate dosimetry, coupled with the toxic side-effects of yttrium treatment, make iodine-131 the current isotope of choice.

Haemodynamic and transport barriers to the treatment of solid tumours

The efficacy in cancer treatment of novel therapeutic agents such as monoclonal antibodies, cytokines and effector cells has been limited by their inability to reach their target in vivo in adequate quantities. Molecular and cellular biology of neoplastic cells alone has failed to explain the nonuniform uptake of these agents. This is not surprising since a solid tumour in vivo is not just a collection of cancer cells. In fact, it consists of two extracellular compartments: vascular and interstitial. Since no blood-borne molecule or cell can reach cancer cells without passing through these compartments, the vascular and interstitial physiology of tumours has received considerable attention in recent years. Three physiological factors responsible for the poor localization of macromolecules in tumours have been identified: (i) heterogeneous blood supply, (ii) elevated interstitial pressure, and (iii) large transport distances in the interstitium. The first factor limits the delivery of blood-borne agents to well-perfused regions of a tumour; the second factor reduces extravasation of fluid and macromolecules in the high interstitial pressure regions and also leads to an experimentally verifiable, radially outward convection in the tumour periphery which opposes the inward diffusion; and the third factor increases the time required for slowly moving macromolecules to reach distal regions of a tumour. Binding of the molecule to an antigen further lowers the effective diffusion rate by reducing the amount of mobile molecule. Although the effector cells are capable of active migration, peculiarities of the tumour vasculature and interstitium may also be responsible for poor delivery of lymphokine activated killer cells and tumour infiltrating lymphocytes in solid tumours. Due to micro- and macroscopic heterogeneities in tumours, the relative magnitude of each of these physiological barriers would vary from one location to another and from one day to the next in the same tumour, and from one tumour to another. If the genetically engineered macromolecules and effector cells, as well as low molecular weight cytotoxic agents, are to fulfill their clinical promise, strategies must be developed to overcome or exploit these barriers. Some of these strategies are discussed, and situations wherein these barriers may not be a problem are outlined. Finally, some therapies where the tumour vasculature of the interstitium may be a target are pointed out.

A randomized prospective trial comparing full dose chemotherapy to 131I antiferritin: an RTOG study

A previously reported Phase I/II multimodality program for non-resectable hepatocellular cancer began with external beam-radiation and chemotherapy, followed by administration of 131I antiferritin-specific radioimmunoglobulin and led to a 48% remission (7% complete remission and 41% partial remission). Survival and response depended on alpha fetoprotein status. AFP+ patients had a median survival of 5 months; AFP- patients had a median survival of 10.5 months. No acute effects occurred relative to treatment with radiolabeled antibody. A randomized prospective study was designed to compare full dose chemotherapy consisting of 60 mg/m2, doxorubicin and 500 mg/m2 of 5-fluorouracil administered every 3 weeks, to 131I antiferritin administration every 8 weeks and allowed for crossover treatment if tumor progression occurred. Overall, radiolabeled antibody administration and full dose chemotherapy led to equivalent partial remission rates (22-30% vs 23-25%) and survival rates compared to chemotherapy (6 month median; AFP+ 5 months; AFP- 10 months). The most important new observations were the response in AFP- patients who, following chemotherapy failure, achieved remission using 131I radiolabeled antibody (7/11) and a subset of patients (7%) who were treated with radiolabeled antibody and converted from non-resectable to resectable status followed by surgical excision.

Cytoreduction and sequential resection: a hope for unresectable primary liver cancer

For decades, unresectable primary liver cancer (PLC) determined by operation was incurable. However, a retrospective study of 24 years' materials with unresectable PLC indicated that 5-year survival of unresectable PLC has increased from 0% in 1966-1977 (n = 137) to 16.9% in 1978-1989 (n = 345). This encouraging improvement was mainly a result of cytoreduction therapy followed by sequential resection. Multimodality combination treatment with hepatic artery ligation, plus hepatic artery infusion with chemotherapy, plus radioimmunotherapy (or radiotherapy) yielded the highest sequential resection rate (30.6%) and 5-year survival (28.0%) as compared with double combination and single modality treatment. The 5-year survival of 33 patients receiving sequential resection after cytoreduction therapy was 63.2%. It is suggested that cytoreduction and sequential resection might offer a hope for surgically verified unresectable PLC.

Vascular and interstitial barriers to delivery of therapeutic agents in tumors

The efficacy in cancer treatment of novel therapeutic agents such as monoclonal antibodies, cytokines and effector cells has been limited by their inability to reach their target in vivo in adequate quantities. Molecular and cellular biology of neoplastic cells alone has failed to explain the nonuniform uptake of these agents. This is not surprising since a solid tumor in vivo is not just a collection of cancer cells. In fact, it consists of two extracellular compartments: vascular and interstitial. Since no blood-borne molecule or cell can reach cancer cells without passing through these compartments, the vascular and interstitial physiology of tumors has received considerable attention in recent years. Three physiological factors responsible for the poor localization of macromolecules in tumors have been identified: (i) heterogeneous blood supply, (ii) elevated interstitial pressure, and (iii) large transport distances in the interstitium. The first factor limits the delivery of blood-borne agents to well-perfused regions of a tumor; the second factor reduces extravasation of fluid and macromolecules in the high interstitial pressure regions and also leads to an experimentally verifiable, radially outward convection in the tumor periphery which opposes the inward diffusion; and the third factor increases the time required for slowly moving macromolecules to reach distal regions of a tumor. Binding of the molecule to an antigen further lowers the effective diffusion rate by reducing the amount of mobile molecule. Although the effector cells are capable of active migration, peculiarities of the tumor vasculature and interstitium may be also responsible for poor delivery of lymphokine activated killer cells and tumor infiltrating lymphocytes in solid tumors. Due to micro- and macroscopic heterogeneities in tumors, the relative magnitude of each of these physiological barriers would vary from one location to another and from one day to the next in the same tumor, and from one tumor to another. If the genetically engineered macromolecules and effector cells, as well as low molecular weight cytotoxic agents, are to fulfill their clinical promise, strategies must be developed to overcome or exploit these barriers. Some of these strategies are discussed, and situations wherein these barriers may not be a problem are outlined. Finally, some therapies where the tumor vasculature or the interstitium may be a target are pointed out.

Radiobiological aspects of low dose rates in radioimmunotherapy

It is assumed that initial dose rates of 10-20 cGy/hour and total doses of 1500-2000 cGy, delivered with effective half-lives of a few days, are reasonable starting points for assessing the radiobiological effects of such low and declining dose rates. Such doses might kill 2 or 3 logs of cells out of the 9 or 10 required for tumor eradication; this is well known. The emphasis in this paper is on the change of effectiveness (per Gy) with change in dose rate. Biological effectiveness, in terms of log cell kill per Gy, will be less than that of higher dose rates because there is more time for repair of sublethal radiation injury. This loss in Relative Effectiveness, RE, is unlikely to exceed 20% in most types of tumor cell, compared with conventional external beam radiation schedules. Therefore, a tumor or metastatic deposit that would require 60-70 Gy to sterilize it using conventional radiotherapy with 2 Gy fractions (or traditional radioactive implants at 50 cGy/hr) would require 70-84 Gy at the lower dose rates available from radioimmunotherapy. This is the major dose rate effect and so far we have ignored proliferation. In the dose-rate range of 10-300 cGy/hr in vitro, highly variable depending on type of cell, division might be prevented but not progression through the cell cycle. Additional cell kill is observed because cells accumulate in the radiosensitive G2 phase; this is the inverse dose-rate effect. However, that range of dose rates comes from in vitro experiments where cells are doubling in number every 0.5 to 1 day. In vivo they double more slowly so it is possible that the unpredictable benefit of G2 accumulation, or partial synchrony, could occur at lower dose rates than 10 cGy/hr in human tumors. The dose rates necessary to kill cells at exactly the rate they are proliferating (which of course would not alone eradicate tumors or metastases) can be calculated, if values are assumed for intrinsic radiosensitivity and doubling rate of cells. In median ranges, dose rates of 2-3 cGy/hr should just counteract proliferation. Higher dose rates, maintained for a few days, could cause 2 or 3 logs of cell kill which would be observed as partial regression, as has been reported clinically and in animal experiments.

Systemic radiotherapy--the new frontier

The present day use of systemically administered isotopes and conjugated isotopic combinations are reviewed. Administration of 131Iodine in thyroid cancer led to a 97% local control and 50% complete remission of pulmonary metastases. Specificity directed isotopic therapy (metabolic, hormonal, and antibody) is discussed and includes factors such as tumor physiology and isotopic linkage. The clinical results and new knowledge being gained in Hodgkin's disease, non-Hodgkin's, colorectal, hepatoma, intrahepatic biliary and gliomatous cancers are reviewed. The dose response relationship to tumor remission is demonstrated in Hodgkin's treated with 131I antiferritin (40% partial remission) and more recently 90Yttrium antiferritin (50% complete response). Varied routes of administration, the problem of anti-antibody and bone marrow transplantation are discussed. Finally, the challenge to radiobiologists, physicists, chemists, immunologists, nuclear radiologists, and radiation oncologists is emphasized by definition of the new laboratory and clinical approaches being developed in systemic radiation therapy.

Radioimmunotherapy in the multimodality treatment of hepatocellular carcinoma with reference to second-look resection

Experimental study using nude mice human hepatocellular carcinoma (HCC) xenograft indicated that the combination treatment with iodine 131 (131I)-anti-human HCC isoferritin (131I-isoFtAb), cisplatin, and mixed bacterial vaccine (MBV) yielded better inhibition rate as compared with double combination or 131I-isoFtAb alone. Based on these findings, 25 patients with surgically proven nonresectable and pathologically proven HCC have been treated by radioimmunotherapy using 131I-isoFtAb intrahepatic arterial infusion as a part of multimodality treatment. Of the 25 patients, seven (28.0%) received second-look resection after marked shrinkage of tumor. The 1-year survival was 52.5% (12/23) and 2-year survival 27.7% (five of 18) in the entire series. Of the five patients with 2-year survival, four were in the second-look resection group. Patients with tumor less than or equal to 8 cm showed higher second-look resection rate (62.5% versus 11.8%) and 1-year survival (85.7% versus 37.5%) as compared with tumor greater than 8 cm. Mixed bacterial vaccine as adjuvant immunotherapy seemed effective to prolong survival. The 2-year survival was higher in patients with second-look resection as compared with those without (75.0% versus 14.3%). Thus, radioimmunotherapy using 131I-isoFtAb might be one of the modalities of choice, particularly in the conversion of nonresectable to resectable HCC in a well-designed multimodality treatment regimen.

The theoretical implications and experimental and clinical results of radiolabeled antiferritin

Ferritin is produced in malignant and normal tissues. It acts both as an immunosuppressant and as an iron storage protein. As a tumor associated protein, it is related to virally induced tumors, and selective tumor targeting by radiolabeled antiferritin antibodies has led to its use in clinical trials. In patients with advanced Hodgkin's disease who have failed conventional therapy, 131I antiferritin produced partial remissions, while 90Y antiferritin led to complete remissions and a demonstrable dose-response relationship. Combining the variable low-dose radiation patterns produced by radiolabeled antibody therapy with chemotherapy in the treatment of hepatocellular cancer has led to enhanced tumor cytotoxicity and, in some cases, the conversion of non-resectable hepatoma to resectable. Further, the potential for clinical and laboratory investigation of radiolabeled antibody therapy is discussed in light of new findings.

Hepatocellular carcinoma: some aspects to improve long-term survival

Sixty-six patients surviving over 5 years after resection of hepatocellular carcinoma (HCC) are investigated. Of them, subclinical stage amounted to 56.1% (37/66) and moderate stage to 43.9% (29/66). There were 35 cases with small HCC (less than or equal to 5 cm). Cirrhosis was present in 81.1% (54/66). Radical resection was performed in 98.5% (65/66) and palliative resection in 1.5% (1/66). Reoperation for subclinical recurrence and solitary pulmonary metastasis was done in 14 patients, and sequential resection of huge tumors, in three patients. By the end of June 1988, follow-up varied from 60 to 319 months (mean, 115 months); 80.3% of the patients (53/66) are still alive and free of disease; 19.7% (13/66) died with disease. The majority of long-term survivors have returned to their original work; some young patients got married after resection of small HCC 10 years ago, and some can even play football again. Some aspects to improve long-term survival are discussed.

Immunoradiotherapy for primary nonresectable hepatocellular carcinoma

The ability to convert a nonrectable lesion into a resectable one offers significant palliation and possible cure for patients with hepatoma. With increasing effectiveness of radiolabeled immunoglobulin and multimodality treatment, more patients are expected to become candidates for definitive resection after presenting with unresectable disease.

The role of liver transplantation in hepatobiliary malignancy. A retrospective analysis of 95 patients with particular regard to tumor stage and recurrence

The role of hepatic transplantation in patients with nonresectable liver or bile duct cancer remains a controversial issue. An analysis of 95 consecutive cases was undertaken to evaluate retrospectively the pathological tumor stage--in accordance with the TNM system--and outcome after transplantation. Included were patients with the following diagnoses: hepatocellular carcinoma (n = 52), cholangiocellular carcinoma (n = 10), hepatoblastoma (n = 2), hemangiosarcoma (n = 2), bile duct carcinoma (n = 20), and liver metastases from different primary tumors (n = 9). The overall actuarial survival rate at 5 years was 20.4%. Median survival improved significantly within the last 4 years as compared to the preceding era (18.06 vs. 4.0 months). Currently 27 patients are alive, with the longest follow-up more than 12 years. The incidences of residual or recurrent tumor were 27 and 28, respectively. Particularly in patients who underwent transplantation for hepatocellular or bile duct carcinoma without extra-hepatic tumor spread, the results were significantly better; median survival time achieved for these two groups were 120 (p less than 0.01) and 35 months (p less than 0.05). Prolonged survival without tumor recurrence was not seen in patients with cholangiocellular carcinoma or liver metastases. These results demonstrate clearly that liver transplantation for hepatobiliary malignancy is still justified on the premises of careful patient selection by adequate tumor staging.

Distribution of injected monoclonal antibody in lymphoma-infiltrated spleen

Specific and non-specific antibody was injected into mice with lymphoma-infiltrated spleens in order to assess the distribution with both time and with extent of tumour infiltration. The specific antibody (MRC OX7) bound to the Thy 1.1 antigen on the lymphoma cells (A120). There was evidence that the diffusion of MRC OX7 deeply into the tumour was hindered by competitive binding to the tumour cells immediately surrounding the supplying blood vessels. In some circumstances this situation persisted to 24 h, after which time the antibodies were being cleared from the host in significant amounts.