Isolated limb perfusion for extremity soft-tissue sarcomas, in-transit metastases, and other unresectable tumors: credits, debits, and future perspectives

Technical considerations for isolated limb perfusion: A consensus paper

BACKGROUND

Isolated limb perfusion (ILP) is a well-established surgical procedure for the administration of high dose chemotherapy to a limb for the treatment of advanced extremity malignancy. Although the technique of ILP was first described over 60 years ago, ILP is utilised in relatively few specialist centres, co-located with tertiary or quaternary cancer centres. The combination of high dose cytotoxic chemotherapy and the cytokine tumour necrosis factor alpha (TNFα), mandates leakage monitoring to prevent potentially serious systemic toxicity. Since the procedure is performed at relatively few specialist centres, an ILP working group was formed with the aim of producing technical consensus guidelines for the procedure to streamline practice and to provide guidance for new centres commencing the technique.

METHODS

Between October 2021 and October 2023 a series of face to face online and hybrid meetings were held in which a modified Delphi process was used to develop a unified consensus document. After each meeting the document was modified and recirculated and then rediscussed at subsequent meeting until a greater than 90% consensus was achieved in all recommendations.

RESULTS

The completed consensus document comprised 23 topics in which greater than 90% consensus was achieved, with 83% of recommendations having 100% consensus across all members of the working group. The consensus recommendations covered all areas of the surgical procedure including pre-operative assessment, drug dosing and administration, perfusion parameters, hyperthermia, leakage monitoring and theatre logistics, practical surgical strategies and also post-operative care, response evaluation and staff training.

CONCLUSION

We present the first joint expert-based consensus statement with respect to the technical aspects of ILP that can serve as a reference point for both existing and new centres in providing ILP.

Isolated limb perfusion for soft tissue sarcoma: Current practices and future directions. A survey of experts and a review of literature

Soft tissue sarcomas constitute 1% of adult malignant tumors. They are a heterogeneous group of more than 50 different histologic types. Isolated limb perfusion is an established treatment strategy for locally advanced sarcomas. Since its adoption for sarcomas in 1992, after the addition of TNFα, few modifications have been done and although indications for the procedure are essentially the same across centers, technical details vary widely. The procedures mainly involves a 60 min perfusion with melphalan and TNFα under mild hyperthermia, achieving a limb preservation rate of 72-96%; with an overall response rates from 72 to 82.5% and an acceptable toxicity according to the Wieberdink scale. The local failure rate is 27% after a median follow up of 14-31 months compared to 40% of distant recurrences after a follow up of 12-22 months. Currently there is no consensus regarding the benefit of ILP per histotype, and the value of addition of radiotherapy or systemic treatment. Further developments towards individualized treatments will provide a better understanding of the population that can derive maximum benefit of ILP with the least morbidity.

Cellular demolition: Proteins as molecular players of programmed cell death

Apoptosis, a well-characterized and regulated cell death programme in eukaryotes plays a fundamental role in developing or later-life periods to dispose of unwanted cells to maintain typical tissue architecture, homeostasis in a spatiotemporal manner. This silent cellular death occurs without affecting any neighboring cells/tissue and avoids triggering of immunological response. Furthermore, diminished forms of apoptosis result in cancer and autoimmune diseases, whereas unregulated apoptosis may also lead to the development of a myriad of neurodegenerative diseases. Unraveling the mechanistic events in depth will provide new insights into understanding physiological control of apoptosis, pathological consequences of abnormal apoptosis and development of novel therapeutics for diseases. Here we provide a brief overview of molecular players of programmed cell death with discussion on the role of caspases, modifications, ubiquitylation in apoptosis, removal of the apoptotic body and its relevance to diseases.

Soft tissue sarcomas of the upper extremities: Maximizing treatment opportunities and outcomes

Soft tissue sarcomas (STS) are rare tumors; they do not even equate to 1% of all malignant tumor cases. One-fifth of all STS occur in the upper extremities, where epithelioid sarcoma, synovial sarcoma, clear cell sarcoma and malignant fibrohistiocytoma are the most frequent subtypes. Surgical resection is the cornerstone of treatment. However, accomplishment of optimal oncological and functional results of STS of the upper extremities may represent a challenge for hand surgeons, due to the complex anatomy. In several cases, preoperative therapies are needed to facilitate tumor resection and improve the oncological outcome. Oligometastatic disease may also be a challenging scenario as curative strategies can be applied. Radiotherapy and chemotherapy are commonly used for this purpose albeit with conflicting evidence. Novel drug combinations have also been approved in the metastatic setting, further improving the quality of life and survival of eligible patients. Thus, prior to any approach, every case should be individually discussed in sarcoma centers with specialized multidisciplinary tumor boards. The aim of the present review was to gather the multidisciplinary experiences of the available therapeutic strategies for STS of the upper extremities.

In Vivo Bioorthogonal Chemistry Enables Local Hydrogel and Systemic Pro-Drug To Treat Soft Tissue Sarcoma

The ability to activate drugs only at desired locations avoiding systemic immunosuppression and other dose limiting toxicities is highly desirable. Here we present a new approach, named local drug activation, that uses bioorthogonal chemistry to concentrate and activate systemic small molecules at a location of choice. This method is independent of endogenous cellular or environmental markers and only depends on the presence of a preimplanted biomaterial near a desired site (e.g., tumor). We demonstrate the clear therapeutic benefit with minimal side effects of this approach in mice over systemic therapy using a doxorubicin pro-drug against xenograft tumors of a type of soft tissue sarcoma (HT1080).

Hepatic arterial infusion with tumor necrosis factor-α induces early hepatic hyperperfusion

BACKGROUND

Hepatic arterial infusion (HAI) has been developed for high-dose regional chemotherapy of unresectable liver metastases or primary liver malignancies. While it is well known that high concentrations of tumor necrosis factor (TNF)-α damage tumor blood perfusion, there is no information on whether autochthonous liver perfusion is affected by HAI with TNF-α. Therefore, we investigated the effects of HAI with TNF-α on hepatic macro- and microvascular perfusion.

METHODS

Swabian Hall pigs were randomized into three groups. HAI was performed with either 20 or 40 µg/kg body weight TNF-α (n = 6 each group). Saline-treated animals served as controls (n = 6). Analyses during a 2-hour post-HAI observation period included systemic hemodynamics, portal venous and hepatic arterial blood flow, portal venous pressure, and the blood flow in the hepatic microcirculation.

RESULTS

HAI with TNF-α caused a slight decrease of mean arterial blood pressure (p < 0.001), which was compensated by a moderate increase of heart rate (p < 0.001). No further systemic side effects of TNF-α were observed. HAI with TNF-α further caused a slight but not significant decrease of portal venous blood flow (p = 0.737) in both experimental groups, paralleled by an increase of hepatic arterial blood flow (p = 0.023, 20 µg/kg; p = 0.034, 40 µg/kg) resulting in an overall hepatic hyperperfusion. The hepatic hyperperfusion after HAI with 20 µg/kg TNF-α was more pronounced and associated with a 40% decrease of the blood flow in the hepatic microcirculation (p = 0.009). HAI with 40 µg/kg TNF-α was only associated with a temporary and moderate total hepatic hyperperfusion and did not affect the blood flow in the hepatic microcirculation.

CONCLUSION

HAI with TNF-α causes a decrease of portal venous flow; however, this is overcompensated by an increased hepatic arterial blood flow, resulting in a total hepatic hyperperfusion. Moderate total hepatic hyperperfusion does not affect the blood flow in the hepatic microcirculation, while a persistent and more pronounced hyperperfusion may cause hepatic microcirculatory disturbances.

[Tumor necrosis factor α and melfalan-based hyperthermic isolated limb perfusion in locally advanced extremity soft tissue sarcomas and melanomas]

INTRODUCTION

The aim of the study is to evaluate the limb salvage rate achieved by treating locally advanced extremity sarcoma and melanoma by hyperthermic isolated limb perfusion with melphalan and TNF-α (ILP-MT).

MATERIAL AND METHODS

A retrospective study was conducted on patients suffering from locally advanced soft tissue sarcoma and melanoma of the limb and treated by means of ILP-MT between November 2001 and February 2010. The response rate, toxicity, complications, disease free intervals, overall survival and limb salvage rate were evaluated.

RESULTS

A total of 30 patients (19 females and 11 males) with a median age of 60 years (14-82) were treated by this technique. The overall response rate was 93.4% (complete, 46.7%; partial 46.7%); the mean follow-up was 23 months. The median duration of response was 5 months (0-62), The median overall survival was 13.5 months (range 1 - 62). Limb salvage rate was 86.7%. Eleven patients are currently alive (5 without disease, 2 with residual disease on treatment, 2 with local progression and 2 with systemic progression).

CONCLUSION

With the use of ILP-MT we have avoided the amputation of 26 limbs affected by locally advanced sarcoma or melanoma. ILP-MT is feasible and safe in a multidisciplinary environment.

Crosstalk between TNF and glucocorticoid receptor signaling pathways

TNF is a Janus-faced protein. It possesses impressive anti-tumor activities, but it is also one of the strongest known pro-inflammatory cytokines, which hampers its use as a systemic anti-cancer agent. TNF has been shown to play a detrimental role in inflammatory diseases such as rheumatoid arthritis and inflammatory bowel disease. Glucocorticoids are strongly anti-inflammatory and exert their therapeutic effects through binding to their receptor, the glucocorticoid receptor. Therefore, glucocorticoids have been used for over half a century for the treatment of inflammatory diseases. However, many patients are or become resistant to the therapeutic effects of glucocorticoids. Inflammatory cytokines have been suggested to play an important role in this steroid insensitivity or glucocorticoid resistance. This review aims to highlight the mechanisms of mutual inhibition between TNF and GR signaling pathways.

Developments in the Management of Extremity Soft Tissue Sarcomas

Soft tissue sarcomas, a rare and extremely low prevalence tumor, has no uniform treatment recommendation because there have been few randomized prospective trials to guide management. Recently, there have been surgical, medical, biologic, and genetic advances toward improved treatment. A multidisciplinary approach at specialized treatment centers should be sought because the skill set necessary to implement these advances can be provided and outcomes improved. Centralized care will be crucial to improving survival and functional outcome because it will allow for patients to be effectively entered into prospective randomized trials and create regional and national tissue banks to generate meaningful data.

Death receptors as targets for anti-cancer therapy

Human tumour cells are characterized by their ability to avoid the normal regulatory mechanisms of cell growth, division and death. The classical chemotherapy aims to kill tumour cells by causing DNA damage-induced apoptosis. However, as many tumour cells possess mutations in intracellular apoptosis-sensing molecules like p53, they are not capable of inducing apoptosis on their own and are therefore resistant to chemotherapy. With the discovery of the death receptors the opportunity arose to directly trigger apoptosis from the outside of tumour cells, thereby circumventing chemotherapeutic resistance. Death receptors belong to the tumour necrosis factor receptor superfamily, with tumour necrosis factor (TNF) receptor-1, CD95 and TNF-related apoptosis-inducing ligand-R1 and -R2 being the most prominent members. This review covers the current knowledge about these four death receptors, summarizes pre-clinical approaches engaging these death receptors in anti-cancer therapy and also gives an overview about their application in clinical trials conducted to date.

Tumoricidal activity of high-dose tumor necrosis factor-alpha is mediated by macrophage-derived nitric oxide burst and permanent blood flow shutdown

This study investigates the role of tumor nitric oxide (NO) and vascular regulation in tumor ulceration following high-dose tumor necrosis factor-alpha (TNF) treatment. Using TNF-responsive (MethA) and nonresponsive (LL2) mouse tumors, tumor NO concentration was measured with an electrochemical sensor and tumor blood flow by Doppler ultrasound. Mice were also pretreated with a selective inducible nitric oxide synthase (iNOS) inhibitor, 1400 W. Tumors harvested from TNF-treated mice were cryosectioned and immunostained for murine macrophages, or/and iNOS. MethA tumor-bearing mice were depleted of macrophages. Pre- and post-TNF tumor NO levels were measured continuously, and mice were followed for gross tumor response. In MethA tumors, TNF caused a 96% response rate, and tumor NO concentration doubled. Tumor blood flow decreased to 3% of baseline by 4 hr and was sustained at 24 hr and 10 days post-TNF. Selective NO inhibition with 1400 W blocked NO rise and decreased response rate to 38%. MethA tumors showed tumor infiltration by macrophages post-TNF and the pattern of macrophage immunostaining overlapped with iNOS immunostaining. Depletion of macrophages inhibited tumor NO increase and response to TNF. LL2 tumors had a 0% response rate to TNF and exhibited no change in NO concentration. Blood flow decreased to 2% of baseline by 4 hr, recovered to 56% by 24 hr and increased to 232% by 10 days. LL2 tumors showed no infiltration by macrophages post-TNF. We conclude that TNF causes tumor infiltrating, macrophage-derived iNOS-mediated tumor NO rise and sustained tumor blood flow shutdown, resulting in tumor ulceration in the responsive tumor.

Cutting-Edge Apoptosis-Based Therapeutics

Defects in programmed cell death or apoptosis are major hallmarks of cancer contributing to tumorigenesis, tumor progression, and therapy resistance. In the past decade, many of the pathways leading to apoptosis, as well as the molecular mechanisms blocking the death of tumor cells, have been elucidated. This detailed knowledge of the core apoptosis machinery is now being exploited for translation into novel cancer therapies in order to restore apoptosis induction in tumor cells. Strategies include activation of proapoptotic mediators such as death receptors, tumor protein p53, and second mitochondria-derived activator of caspases (SMAC)/DIABLO as well as inhibition of endogenous apoptosis inhibitors such as IAPs (inhibitor of apoptosis proteins) and BCL-2 (B-cell chronic lymphoid leukemia/lymphoma) proteins. Several approaches employing gene therapy and antisense strategies, recombinant biologics, or classic organic and combinatorial chemistry, have advanced into clinical trials or are already approved. This review looks at recent developments in apoptosis-based cancer therapies and highlights some very promising advances in drug design.

Target-selective activation of a TNF prodrug by urokinase-type plasminogen activator (uPA) mediated proteolytic processing at the cell surface

We have previously developed TNF prodrugs comprised of a N-terminal scFv targeting, a TNF effector and a C-terminal TNFR1-derived inhibitor module linked to TNF via a MMP-2 motif containing peptide, allowing activation by MMP-2-expressing tumor cells. To overcome the known heterogeneity of matrix metalloprotease expression, we developed TNF prodrugs that become processed by other tumor and/or stroma-associated proteases. These TNF prodrugs comprise either an uPA-selective or a dual uPA-MMP-2-specific linker which displayed efficient, target-dependent and cleavage sequence-specific activation by the corresponding tumor cell-expressed proteases. Selective pharmacologic inhibition of endogenous uPA and MMP-2 confirm independent prodrug processing by these two model proteases and indicate the functional superiority of a prodrug containing a multi-specific protease linker. Processing optimised TNF prodrugs should increase the proportion of active therapeutic within the targeted tissue and thus potentially enhance tumor response rate.

Locally advanced and metastatic sarcoma (adult type) including gastrointestinal stromal tumors

STS belong to the most challenging diseases in oncology that demand all resources of modern clinical oncology. With the improvement of surgical techniques and radiation therapy the majority of patients with localized disease can be cured. However, for patients with locally advanced or metastatic disease chemotherapeutic treatments have not greatly changed the poor outcome of the disease. The introduction of combined chemoradiotherapy as well as isolated limb-perfusion has improved the limb-salvage rate in locally advanced disease but the impact of systemic chemotherapy on overall survival remains a subject of dispute. For patients with metastatic sarcoma long-term survival can only be achieved in a small number of patients with mostly resectable disease. The list of effective drugs for palliative treatment in general still remains short and the duration of remissions usually does not exceed several months. The lack of alternative chemotherapeutic drugs imposes a considerable challenge in daily clinical practice with many young patients exhibiting a good performance status but progressive disease after standard treatment. A variety of new drugs or drug combinations seem to exhibit considerable activity in certain histological sarcoma subtypes, which may soon broaden the armamentarium of drugs for a subset of patients. However, with the vastly improved understanding of the biology and pathology of soft tissue sarcoma an era of opportunities seems to have begun and the recent success in the treatment of gastrointestinal stromal tumors impressively shows how fast a gain in the understanding of oncogenic mechanisms may translate into a highly efficient, clinically useful treatment.

Structure-activity profiles of Ab-derived TNF fusion proteins

TNF application in humans is limited by severe side effects, including life-threatening symptoms of shock. Therefore, TNF can be successfully applied as a tumor therapeutic reagent only under conditions that prevent its systemic action. To overcome this limitation, genetic fusion of TNF to tumor-selective Abs is a favored strategy to increase site-specific cytokine targeting. Because wild-type TNF displays its bioactivity as noncovalently linked homotrimer, the challenge is to define structural requirements for a TNF-based immunokine format with optimized structure-activity profile. We compared toxicity and efficacy of a dimerized CH2/CH3 truncated IgG1-TNF fusion protein and a single-chain variable fragment-coupled TNF monomer recognizing fibroblast-activating protein. The former construct preserves its dimeric structure stabilized by the natural disulfide bond IgG1 hinge region, while the latter trimerizes under native conditions. Analysis of complex formation of wild-type TNF and of both fusion proteins with TNFR type 1 (TNF-R1) using surface plasmon resonance correlated well with in vitro and in vivo toxicity data. There is strong evidence that TNF subunits in a trimeric state display similar toxicity profiles despite genetic fusion to single-chain variable fragment domains. However, LD(50) of either immunodeficient BALB/c nu/nu or immunocompetent BALB/c mice was significantly decreased following administration of TNF in the formation of IgG1-derived dimeric fusion protein. Reduction of unspecific peripheral complexation of TNF-R1 resulted in higher anticancer potency by immunotargeting of fibroblast-activating protein-expressing xenografts. The broader therapeutic window of the IgG1-derived TNF fusion protein favors the dimeric TNF-immunokine format for systemic TNF-based tumor immunotherapy.

Apoptosis-based therapies and drug targets

The pathogenesis of many diseases is most closely connected with aberrantly regulated apoptotic cell death. The past 15 years have witnessed an explosion in the basic knowledge of mechanisms that regulate apoptosis and the mediators that either trigger or inhibit cell death. Consequently, great interest has emerged in devising therapeutic strategies for modulating the key molecules of life-and-death decisions. Numerous novel approaches are currently being followed employing gene therapy and antisense strategies, recombinant biologics or classical organic and combinatorial chemistry in order to target specific apoptotic regulators. Although drug development is still in its infancy, several therapeutics have progressed to clinical testing or have even been approved in record time. This review outlines the recent advances in the field of apoptosis-based therapies and explores some highlights of a very active field of drug development.

New approaches and therapeutics targeting apoptosis in disease

Apoptosis, the major form of cellular suicide, is central to various physiological processes and the maintenance of homeostasis in multicellular organisms. Presumably, even more important is a causative or contributing role of apoptosis to various human diseases. These include situations with unwanted cell accumulation (cancer) and failure to eradicate aberrant cells (autoimmune diseases) or disorders with an inappropriate loss of cells (heart failure, stroke, AIDS, neurodegenerative diseases, and liver injury). The past decade has witnessed a tremendous progress in the knowledge of the molecular mechanisms that regulate apoptosis and the mediators that either prevent or trigger cell death. Consequently, apoptosis regulators have emerged as key targets for the design of therapeutic strategies aimed at modulating cellular life-and-death decisions. Numerous novel approaches are currently being followed employing gene therapy and antisense strategies, recombinant biologics, or classical organic and combinatorial chemistry to target specific apoptotic regulators. Convincing proof-of-principle evidence obtained in several animal models confirms the validity of strategies targeting apoptosis and revealed an enormous potential for therapeutic intervention in a variety of illnesses. Although numerous apoptotic drugs are currently being developed, several therapeutics have progressed to clinical testing or are already approved and marketed. Here we review the recent progress of apoptosis-based therapies and survey some highlights in a very promising field of drug development.

Restoration of membrane TNF-like activity by cell surface targeting and matrix metalloproteinase-mediated processing of a TNF prodrug

Tumor necrosis factor (TNF) prodrugs are fusion proteins comprised of an N-terminal single-chain antibody variable fragment (scFv) targeting a TNF effector and a C-terminal TNF receptor (TNFR)1-derived inhibitor module. Introduction of matrix metalloproteinase (MMP)-2 recognition motifs between TNF and the TNFR1 fragment allowed activation by recombinant MMP-2 and MMP-expressing HT1080 cells. Processing by endogeneous MMPs required specific membrane binding of the TNF prodrug via the targeting scFv, ensuring strictly antigen-dependent activation. Interestingly, TNF bioactivity of the processed prodrug was approximately 1000-fold higher upon scFv-mediated targeting, and signaled juxtatropic cell death also to antigen-negative cells. Microscopical analyses of TNFR2 clustering and TNF receptor-associated factor 2 recruitment at contact sites to adjacent cells revealed the formation of stable TNFR complexes by target-bound, processed prodrug, resembling the increased signal capacity of natural, membrane-expressed TNF. MMP-2-sensitive TNF prodrugs represent novel cytokine-based reagents for targeted cancer therapy, which should be exploitable for MMP-overexpressing tumors.

Histamine combined with melphalan in isolated limb perfusion for the treatment of locally advanced soft tissue sarcomas: preclinical studies in rats

PURPOSE

To evaluate the potential benefit of histamine combined with melphalan in the isolated limb perfusion (ILP) as an alternative to TNF-alfa and melphalan combination, for the treatment of irresectable soft tissue sarcomas of the limbs in Brown Norway (BN) rats.

METHODS

20 BN rats had small fragments of syngeneic BN-175 fibrosarcoma inserted on the right hind limb. In 7-10 days the tumor reached a median diameter of 12-15 mm and they were randomly divided in four groups (sham, melphalan, histamine and escalating doses of histamine combined to melphalan) being submitted to experimental ILP for 30 minutes. Tumors were measured daily with a caliper and the volume was calculated.

RESULTS

Response curves showed a significant effect of the combination of histamine 200 mg/mL with melphalan, with 66% overall response, including 33% complete responses (p< 0.01). There were no systemic collateral effects and locally only mild temporary edema was observed for some animals treated with histamine.

CONCLUSION

Histamine combined with melphalan had a promising effect in the ILP warranting future studies to better explore the mechanism of action as well as its potential use in organ perfusion.

Doppler US with perfusion software and contrast medium injection in the early evaluation of isolated limb perfusion of limb sarcomas: prospective study of 49 cases

BACKGROUND

The aim of this study was to prospectively evaluate the use of Doppler ultrasonography with perfusion software and contrast agent injection (DUPC) during isolated limb perfusion (ILP) with high-dose chemotherapy and TNF-alpha(biochemotherapy) in patients with locally advanced extremity soft tissue sarcoma (STS).

PATIENTS AND METHODS

Fifty-two patients were prospectively included in this monocentric imaging trial. Three were excluded because the study was incomplete in two patients and one tumour did not exhibit any contrast uptake. DUPC was performed before ILP and on days 1, 7, 15, 30 and 60 after ILP. A total of 292 DUPC were performed on 55 target lesions in 49 evaluable patients. The percentage of contrast uptake was evaluated at each tumour site by two radiologists. The criterion tested was a decrease of more than 50% in intra-tumour contrast uptake compared to the pre-ILP examination. Results were compared with both MRI and histological analysis after resection of residual disease.

RESULTS

According to MRI and the histological analysis, 25 (51%) patients were good responders (no difference between the four treatment arms) with tumour necrosis exceeding 90% and 24 (49%) were poor responders. As of day +1, the accuracy of DUPC in predicting tumour response was 82% (18/25 good responders and 22/24 poor responders) increasing to 91% at day +7, 95% at day +15 and 96% at day +30. At day +15, DUPC was predictive of a good response in 100% of the cases.

CONCLUSION

DUPC is a simple technique, allowing early prediction of tumour response after ILP. A new treatment planning scheme can be proposed based on the results of this study.

Hyperthermic Isolated Perfusion With Low-Dose Tumor Necrosis Factor α and Doxorubicin for the Treatment of Limb-Threatening Soft Tissue Sarcomas

BACKGROUND

Tumor necrosis factor (TNF)-alpha-based hyperthermic isolated limb perfusion (HILP) is one of the most active available approaches for locally advanced soft tissue sarcomas (STS) of the limbs. The aim of this study was to investigate the anticancer activity of a novel drug regimen including doxorubicin (DXR) and low-dose TNF-alpha.

METHODS

HILP with low-dose TNF-alpha (1 mg) and DXR (8.5 mg/L of limb volume) was given to 21 patients with limb-threatening STS: 14 had primary and 7 had recurrent STS, most of which were high grade (grade 1, n = 3; grade 2, n = 6; grade 3, n = 12). Resection of the tumor remnant was performed 6 to 8 weeks after HILP. TNF-alpha concentrations in plasma and perfusate were measured throughout perfusion.

RESULTS

A major tumor response was observed at histology and clinical evaluation in 90% and 62% of patients, respectively. After a median follow-up of 30 months, limb salvage and local disease control were achieved in 71% and 81% of cases, respectively. Fourteen patients had moderate regional toxicity, which was resolved in all cases. One patient had severe limb toxicity, which did not require amputation. Systemic side effects were minimal, and there were no postoperative deaths. The perfusate/plasma area under the curve ratio for TNF-alpha was 56.

CONCLUSIONS

HILP with low-dose TNF-alpha and DXR seems to be an active neoadjuvant drug regimen against limb-threatening STS. This therapeutic approach can achieve high limb-sparing surgery rates with acceptable local and negligible systemic toxicity.

Emerging treatments for soft tissue sarcoma of adults

Soft tissue sarcomas are a heterogeneous group of malignancies arising from mesenchymal tissues. Patients can present with a localised tumour (primary or local recurrence) at different sites (e.g., extremity, abdomen) or metastatic disease, which may require different treatment strategies. Is the surgical resection of a localised sarcoma enough or is it better to give an additional treatment like adjuvant and/or preoperative radiotherapy and/or chemotherapy? Which chemotherapy should be selected in the first or second line situation? Do new treatment options exist, such as targeted therapies? This review provides answers to some of these questions. To decide on consecutive treatment steps, it is important to know as many relevant factors as possible at first presentation. Therefore, the first part of this review discusses the specific characteristics and prognostic factors of importance for treatment planning. A short summary of current therapy strategies and existing standards is then given. The main body of the review summarises information on new and emerging clinical compounds for patients with soft tissue sarcoma of adults, including recent developments of targeted therapy.

Dynamic contrast-enhanced MRI using macromolecular contrast media for monitoring the response to isolated limb perfusion in experimental soft-tissue sarcomas

The objective of this study was to evaluate the potential of dynamic contrast-enhanced MRI for quantitative characterization of tumor microvessels and to assess the microvascular changes in response to isolated limb perfusion with TNF-alpha and melphalan. Dynamic contrast-enhanced MRI was performed in an experimental cancer model, using a macromolecular contrast medium, albumin-(Gd-DTPA)45. Small fragments of BN 175, a soft-tissue sarcoma, were implanted in 11 brown Norway (BN) rats. Animals were assigned randomly to a control (Haemaccel) or drug-treated group (TNF-alpha/melphalan). MRI was performed at baseline and 24 h after ILP. The transendothelial permeability (K(PS)) and the fractional plasma volume (fPV) were estimated from the kinetic analysis of MR data using a two-compartment bi-directional model. K(PS) and fPV decreased significantly in the drug-treated group compared to baseline (p<0.05). In addition, K(PS) post therapy was significantly lower (p<0.05) in the drug-treated group than in the control group. There was no significant difference in fPV between the drug-treated and the control group after therapy. Tumor microvascular changes in response to isolated limb perfusion can be determined after 24 h by dynamic contrast-enhanced MRI. The data obtained in this experimental model suggest possible applications in the clinical setting, using the appropriate MR contrast agents.

Melanoma - what is new in sentinel node biopsy and locoregional treatments in 2003? Report of a workshop at the Third Research Meeting on Melanoma, Milan, Italy, May 2003

This paper reports on the scientific session on sentinel node biopsy, surgery and locoregional treatments that took place during the Third Research Meeting on Melanoma, Milan, Italy, held in May 2003. It provides an overview of contributions presented at the meeting grouped according to subject - ultrasound scanning, sentinel node biopsy, mini-invasive surgery and stop-flow limb perfusion. The main comments made by the respective rapporteurs are also summarized.

A bispecific antibody to enhance radiotherapy by tumor necrosis factor-alpha in human CEA-expressing digestive tumors

Tumor necrosis factor-alpha (TNF-alpha) enhances X-ray killing of human tumor cells in vitro and enhances tumor control when combined with radiotherapy (RT) in animal tumor models. In multiple Phase I studies, intravenous injection of TNF-alpha appeared to have severe systemic side effects. To overcome these limitations, we used a bispecific antibody (BAb) directed against carcinoembryonic antigen and human TNF-alpha to target this cytokine in human digestive carcinoma treated with simultaneous RT. We used human digestive carcinoma cell lines (colon cancer, LS174T, and pancreatic cancer, BxPC-3) to determine the interaction of TNF-alpha and RT on clonogenic cytotoxicity. Isobolograms were established to confirm additive or supra-additive effects between both treatments. LS174T and BxPC-3 cells were grafted subcutaneously at Day 0 into female nude mice (7-8 weeks old). When the tumors reached a volume of about 80 mm(3), the mice were randomly assigned to treatment: Group 1, normal saline i.v. injection (control group); Group 2, TNF-alpha at 1 microg/i.v. injection; Group 3, BAb at 25 microg/i.v. injection; Group 4, BAb plus TNF-alpha (ratio 25 microg to 1 microg) i.v. injection; Group 5, local RT plus normal saline (0.5 Gy. min(-1)) at a total dose of 30 Gy delivered in five fractions; Group 6, local RT plus TNF-alpha injections 3 h before RT; Group 7, local RT plus BAb plus TNF-alpha co-injected 24 h before RT. Tumor growth delay was used as the end point for all groups. In the LS174T experiments, TNF-alpha added 12 h before RT showed a statistically significant decrease in the survival fraction at 2 Gy compared with RT alone (0.23 vs. 0.42 Gy, p = 0.0017). These results were largely confirmed with the BxPC-3 cell lines (0.29 vs. 0.72, p <0.00001). Isobolograms confirmed the additivity between TNF-alpha and RT in both cell lines. At 50% survival, the data points were within the envelope of additivity. In the LS174T and BxPC-3 xenografts, RT as a single agent (Group 5) slowed tumor progression compared with Group 1 (p <0.027 and p = 0.00001, respectively). TNF-alpha alone, BAb alone, or BAb plus TNF-alpha (Groups 2, 3, and 4) had no effect. In the LS174T model, TNF-alpha plus RT enhanced the delay to reach 2000 mm(3) compared with RT alone but without statistical significance. This delay was significantly longer when BAb was added (p = 0.0033, for Group 6 vs. Group 7). In the BxPC-3 experiments, the median delay to reach 2000 mm(3) was similar between the RT and TNF-alpha plus RT groups (93 days). The use of our BAb in combination with TNF-alpha and RT dramatically enhanced this median delay (177 days, p = 0.0013). No body weight loss was observed in any group. Our data could be used as a solid preclinical rationale on which to base a clinical study of locally advanced pancreatic or rectal cancers in the near future.

Isolated limb perfusion with tumor necrosis factor-? and melphalan for patients with unresectable soft tissue sarcoma of the extremities

BACKGROUND

Since 1992, isolated limb perfusion (ILP) with tumor necrosis factor-alpha (TNFalpha) and melphalan has been used for the treatment of patients with unresectable soft tissue sarcomas of the extremities. The authors retrospectively studied the results of limb salvage surgery using TNFalpha-ILP at their institution.

METHODS

From 1992 to 2001, 49 patients (mean age, 51 years; range, 14-85 years) underwent ILP for unresectable soft tissue sarcomas of the extremities. All patients received melphalan and TNFalpha (four patients also received interferon-gamma). The median follow-up was 26 months (range, from 2 days to 103 months).

RESULTS

In 1 patient (2%) who died 2 days after undergoing ILP, response and acute limb toxicity could not be assessed. One patient (2%) attained a clinical complete response (2%), 23 patients (47%) attained a clinical partial response, 17 patients (35%) demonstrated no change, and 7 patients (14%) had tumor progression. Thirty-one patients (63%) underwent tumor resection. Histologic material also was available from eight amputations and three punctures/biopsies. Pathologic response was complete in 4 patients (8%), partial in 14 patients (29%), and no change was observed in 24 patients (49%). Final response, based on both clinical and pathologic assessment in which pathology was decisive, was complete in 4 patients (8%) and partial in 27 patients (55%), resulting in a final overall response rate of 63%. Local control with preservation of the limb was attained in 28 patients (57%). Four of 32 patients (13%) who had been rendered tumor free by ILP with or without undergoing resection and radiation therapy, developed a local recurrence. The 5-year disease specific survival rate was 48% for the 49 patients. Acute limb toxicity after ILP was a mild Grade 1-2 reaction in 35 patients (71%) patients, a Grade 3 reaction in 12 patients (25%), and a Grade 4 reaction in 1 patient (2%). Three major ILP-related complications were encountered, including arterial thrombosis in two patients and a fulminant Clostridial infection leading to death in one patient. There were no severe cardiovascular reactions after ILP.

CONCLUSIONS

In patients with unresectable soft tissue sarcomas of the limbs who underwent ILP with TNFalpha and melphalan followed by resection of the tumor remnant when possible, a 63% overall tumor response rate and a 57% local control rate with limb preservation was achieved.

Clinical aspects of a phase I trial of 5,6-dimethylxanthenone-4-acetic acid (DMXAA), a novel antivascular agent

The antitumour action of 5,6-dimethylxanthenone-4-acetic acid (DMXAA) is mediated through tumour-selective antivascular effects and cytokine induction. This clinical phase I trial was conducted to examine its toxicity, maximum tolerated dose, pharmacokinetics (PK) and pharmacodynamics (PD). A secondary objective was to assess its antitumour efficacy. DMXAA was administered every 3 weeks as a 20-min i.v. infusion. Dose escalation initially followed a modified Fibonacci schema but was also guided by PK and toxicity. A total of 63 patients received 161 courses of DMXAA over 19 dose levels ranging from 6 to 4900 mg m(-2). DMXAA was well tolerated at lower doses and no drug-related myelosuppression was seen. Rapidly reversible dose-limiting toxicities were observed at 4900 mg m(-2), including confusion, tremor, slurred speech, visual disturbance, anxiety, urinary incontinence and possible left ventricular failure. Transient prolongation of the corrected cardiac QT interval was seen in 13 patients evaluated at doses of 2000 mg m(-2) and above. A patient with metastatic cervical carcinoma achieved an unconfirmed partial response at 1100 mg m(-2), progressing after eight courses. The results of PK and PD studies are reported separately. DMXAA has antitumour activity at well-tolerated doses.

Isolated limb perfusion with melphalan in the treatment of malignant melanoma of the extremities: a systematic review of randomised controlled trials

Isolated limb perfusion is a surgical procedure for delivering a high dose of chemotherapeutic or immunochemotherapeutic agent to a localised area, thus avoiding the severity of side-effects caused by systemic administration. This technique is generally used for treatment of patients with tumours of the limbs and extremities. We have done a systematic review of randomised controlled trials assessing the effectiveness of this treatment in patients with melanoma of the extremities. Four trials of 1038 patients met our inclusion criteria and were analysed. Although our analysis confirmed the reported increase in survival in two of the trials, neither had sufficient power to detect significant benefit for perfusion. Results from the trials showed that prophylactic perfusion has an equivocal effect on survival in patients with limb melanoma. Therefore, current evidence suggests that prophylactic isolated limb perfusion cannot be recommended as a routine adjunct to standard surgery in patients with high-risk primary limb melanoma, but only as a treatment for local disease control if other forms of locoregional therapy are not available.

Amputation for soft-tissue sarcoma

Soft-tissue sarcomas are a group of rare malignant tumours, many of which arise in the limbs. Most are treated with a combination of wide local excision and radiotherapy, but a small number--including proximal, large, high-grade, or recurrent tumours, or those involving major neurovascular structures--necessitate major amputation including forequarter or hindquarter amputation. These uncommon operations should remain in the surgical armamentarium for carefully selected patients. Those being considered for amputation should be referred to a tertiary sarcoma unit for examination of all other options, such as limb-salvage surgery, tumour downstaging with chemotherapy or radiotherapy (perhaps with subsequent limb-salvage surgery), or novel techniques such as isolated limb perfusion. Only after careful assessment should amputation be carried out. Outcomes after major amputation are highly variable, but such procedures can confer useful palliation to patients with distressing symptoms (pain, bleeding, fungation), long-term disease-free survival with reasonable function in carefully selected patients, and cure in some.

Tumor necrosis factor signaling

A single mouse click on the topic tumor necrosis factor (TNF) in PubMed reveals about 50,000 articles providing one or the other information about this pleiotropic cytokine or its relatives. This demonstrates the enormous scientific and clinical interest in elucidating the biology of a molecule (or rather a large family of molecules), which began now almost 30 years ago with the description of a cytokine able to exert antitumoral effects in mouse models. Although our understanding of the multiple functions of TNF in vivo and of the respective underlying mechanisms at a cellular and molecular level has made enormous progress since then, new aspects are steadily uncovered and it appears that still much needs to be learned before we can conclude that we have a full comprehension of TNF biology. This review shortly covers some general aspects of this fascinating molecule and then concentrates on the molecular mechanisms of TNF signal transduction. In particular, the multiple facets of crosstalk between the various signalling pathways engaged by TNF will be addressed.

Isolated limb perfusion in locally advanced cutaneous melanoma

Isolated limb perfusion (ILP) is a well-established locoregional procedure to deliver high doses of cytostatics to an extremity with multiple in-transit lesions from cutaneous melanoma, with minimal systemic and mild local toxicity. This approach is quite sophisticated and requires accurate monitoring of systemic leakage and of the temperature of the affected limb in order to avoid major systemic and local side effects. Mephalan (L-PAM) is considered the reference drug, although complete responses are reported in only about 50% of patients. Since the early 1990s, tumor necrosis factor-alpha (TNF-alpha) was administered with melphalan in ILP aiming to improve the therapeutic index of this procedure. However, despite the impressive results reported, its role still remains controversial, seemingly confined to large tumor bulk. Fotemustine ILP was proposed as a less toxic alternative to L-PAM, after the results of a pilot experience claiming similar response rates with less local toxicity. A formal phase 1-2 study is now underway to confirm these findings. More straightforward procedures, such as isolated limb infusion, are appealing, as they seem capable of achieving good response rates, are easily repeatable, and are less costly. Larger series are required to validate such results. As potential agents to be delivered through ILP, new vasoactive drugs and agents with new mechanisms of action that interplay with chemotherapy, as well as virus-mediated gene therapy, are being developed.

European approach to adjuvant treatment of intermediate- and high-risk malignant melanoma

Adjuvant therapies for patients with melanoma at high risk of relapse whether local, such as excision margins, elective regional lymph node dissection (ELND), and prophylactic isolated limb perfusion (ILP), or systemic, such as chemotherapy, immunotherapy, immunochemotherapy, or vaccination therapy, have little or no impact on survival when evaluated in randomized trials. The European approach to the treatment of each stage of malignant melanoma is characterized by thoughtful caution with particular attention being paid to the avoidance of unwarranted mutilation or toxicity because phase 3 studies have failed to demonstrate unequivocal benefits for a more aggressive approach. In Europe, there is no standard adjuvant systemic therapy; high-dose interferon (IFN) is used sporadically in individual patients by some physicians, but there is little enthusiasm for adopting this regimen as the standard of care because of its high toxicity profile and the lack of a clear beneficial impact on long-term survival. Less toxic lower-dose maintenance IFN regimens, antiangiogenic agents, and vaccine therapies are currently being explored.

TNF-Selectokine: a novel prodrug generated for tumor targeting and site-specific activation of tumor necrosis factor

We describe a TNF fusion protein designated TNF-Selectokine, which is a homo-trimeric molecule comprised of a single chain antibody (scFv) targeting module, a trimerization domain and TNF. TNF-Selectokine exerts high bioactivity towards the targeted and adjacent, antigen negative cells. Membrane targeting dependent immobilization of the TNF-Selectokine induced cell death in TNFR1 and TNFR2 dependent manner, thus cell bound TNF-Selectokine mimicks membrane TNF. To restrict TNF activity to the tumor, a prototype of a TNF-Selectokine prodrug was constructed by insertion of a TNFR1 fragment, separated from TNF by a protease-sensitive linker. The prodrug exerts minimal TNF activity, but can be activated in vitro several thousand-fold by proteolytic digest, showing the principal feasibility of this approach. Choice of cleavage site(s) recognized by protease(s) typically associated with a given carcinoma should allow high dose systemic application of the respective TNF prodrug that unveils its specific bioactivity only in targeted tissues.

European approach to the treatment of malignant melanoma

The European approach to the treatment of each stage of malignant melanoma can be characterized as cautious, avoiding unwarranted mutilation or toxicity, because phase III trials have demonstrated that an aggressive approach in surgical management, adjuvant therapy, and treatment of stage IV disease has met with little success. Phase III trials have demonstrated that wide margins, elective lymph node dissections, and prophylactic isolated limb perfusions bring no survival benefit. Primary melanoma is excised with a margin of 1 cm to maximally 2 cm and primary closure as a rule. There is no standard adjuvant therapy. High-dose interferon treatment is practiced only sporadically in Europe because its high toxicity profile and an unclear long-term impact on survival are not popular. Long-term nontoxic lower-dose interferon regimens and vaccines are currently being explored. Phase III trials have shown that highly toxic polychemotherapy or biochemotherapy has not produced a survival benefit over simple treatment with dacarbazide alone. In Europe biochemotherapy is being abandoned and various less toxic or nontoxic approaches with vaccines and antiangiogenic agents are under study.

Manipulation of the tumour-associated vasculature to improve tumour therapy

Inhibition of tumour vascular growth, destruction of the tumour associated vasculature (TAV), and manipulation of the endothelial lining of the TAV provide powerful tools for anti-tumour therapy. We previously demonstrated that addition of TNF to chemotherapy improved tumour response. The major effect of TNF is an increased permeability of the tumour vascular bed resulting in augmented accumulation of co-administered drug in the tumour. As the TAV is recognised as a major candidate in tumour therapy it is becoming important to understand anti-vascular effects better. In our laboratory we examine the effect of immunotherapy on the TAV, and the effect of anti tumour-vascular therapy on tumours. This is studied in animal models, which exhibit similarities with the clinical setting, such as tumour perfusion treatment.