Effects of oxygenation and pH on tumor cell response to alkylating chemotherapy

Molecular Aspects of the Isolated Limb Infusion Procedure

For decades, isolated limb infusion (ILI) and hyperthermic isolated limb perfusion (HILP) have been used to treat melanoma in-transit metastases and unresectable sarcoma confined to the limb utilizing the effect of loco-regional high-dose chemotherapy to the isolated limb. Both procedures are able to provide high response rates in patients with numerous or bulky lesions in whom other loco-regional treatments are becoming ineffective. In comparison to systemic therapies, on the other hand, ILI and HILP have the advantage of not being associated with systemic side-effects. Although in principle ILI and HILP are similar procedures, ILI is technically simpler to perform and differs from HILP in that it takes advantage of the hypoxic and acidotic environment that develops in the isolated limb, potentiating anti-tumour activity of the cytotoxic agents melphalan +/− actinomycin-D. Due to its simplicity, ILI can be used in both preclinical and clinical studies to test new cytotoxic regimens and combinations with the aim to overcome tumour resistance. In the future, administration of cytotoxic agents by ILI, in combination with systemic treatments such as BRAF/MEK/KIT inhibitors, immunotherapy (CTLA-4 blockade), and/or programmed death (PD-1) pathway inhibitors, has the potential to improve responses further by inducing increased tumour cell death while limiting the ability of the tumour to suppress the immune response.

A history of exploring cancer in context

The concept that progression of cancer is regulated by interactions of cancer cells with their microenvironment was postulated by Stephen Paget over a century ago. Contemporary tumour microenvironment (TME) research focuses on the identification of tumour-interacting microenvironmental constituents, such as resident or infiltrating non-tumour cells, soluble factors and extracellular matrix components, and the large variety of mechanisms by which these constituents regulate and shape the malignant phenotype of tumour cells. In this Timeline article, we review the developmental phases of the TME paradigm since its initial description. While illuminating controversies, we discuss the importance of interactions between various microenvironmental components and tumour cells and provide an overview and assessment of therapeutic opportunities and modalities by which the TME can be targeted.

Isolated Limb Perfusion and Infusion for Extremity Soft Tissue Sarcoma: A Contemporary Systematic Review and Meta-Analysis

BACKGROUND

Isolated limb perfusion (ILP) and isolated limb infusion (ILI) have been variably used in recent years for the treatment of locally advanced or marginally resectable extremity soft tissue sarcomas (STSs). We performed a systematic review and meta-analysis of contemporary studies to further characterize treatment patterns and outcomes.

METHODS

PubMed was queried for articles published in or after the year 2000, in the English language, with > 10 patients, and with adequate outcome data following ILP/ILI. Descriptive aggregate statistics were performed.

RESULTS

Nineteen studies that met the inclusion criteria were identified, with a total of 1288 patients. Weighted mean patient age was 55.9 years and 52% were male. The majority underwent ILP (88%) versus 12% for ILI, and chemotherapeutic regimens used were as follows: (1) melphalan with tumor necrosis factor (TNF)-α (78%), (2) melphalan ± actinomycin (10%), and (3) other regimens (12%). Most common histologies treated were malignant fibrous histiocytoma (21%), liposarcoma (16%), synovial (11%) and leiomyosarcoma (7%). Aggregate overall response rate (ORR) post-procedure was 73.3%, with 25.8% demonstrating a complete response (CR). Similar unadjusted ORRs were noted in the melphalan treatment groups with and without TNFα (72.0 and 67.0%, respectively; p = 0.27). Grade III toxicity was observed in 15.4% of patients, and grade IV/V toxicity was observed in 6.0% of patients. Overall limb salvage rate was 73.8% and median time to local (in-field) progression ranged from 4 to 28 months (weighted median 22.1 months).

CONCLUSION

ILP and ILI for extremity STS can be safely performed with appreciable response rates and significant limb salvage rates. Further study is needed to identify optimal treatment regimens by histology.

Laparoscopic hyperthermic isolated limb perfusion a new minimally invasive approach for HILP

BACKGROUND

Hyperthermic isolated limb perfusion (HILP) represents a limb-sparing treatment for unresectable soft tissue sarcoma (STS) of the extremities with substantial complete response rates. HILP often provides good functional limb preservation, hence a significant improvement also in terms of quality of life of the patient. Notwithstanding these clear advantages, the traditional technique is still hindered by relatively high post-operative morbidity.

METHOD

We treated a 78-year-old female with unresectable angiosarcoma of the left leg using a new surgical approach: an entirely laparoscopic HILP.

RESULTS

No conversion from laparoscopic to "open" surgery was necessary. Since no abdominal muscle section was performed, post-operative pain was low and easily manageable; early mobilisation and early discharge were achieved. Patient developed moderate toxicity, which resolved spontaneously within 3-4 weeks, with complete return to normal daily activities after 30 d. Complete clinical response with preservation of leg function was obtained.

CONCLUSIONS

We describe for the first time an entirely laparoscopic HILP. Demonstration of this technique's efficacy and safety on a large series of patients is clearly necessary but its therapeutic efficacy appears to be comparable to the standard technique. Furthermore, laparoscopic HILP has shown low post-operative morbidity: no wound complications, mild and easily manageable post-operative pain and early discharge from the hospital and early resuming of daily activities.

Therapeutic implications of tumor interstitial acidification

Interstitial acidification is a hallmark of solid tumor tissues resulting from the combination of different factors, including cellular buffering systems, defective tissue perfusion and high rates of cellular metabolism. Besides contributing to tumor pathogenesis and promoting tumor progression, tumor acidosis constitutes an important intrinsic and extrinsic mechanism modulating therapy sensitivity and drug resistance. In fact, pharmacological properties of anticancer drugs can be affected not only by tissue structure and organization but also by the distribution of the interstitial tumor pH. The acidic tumor environment is believed to create a chemical barrier that limits the effects and activity of many anticancer drugs. In this review article we will discuss the general protumorigenic effects of acidosis, the role of tumor acidosis in the modulation of therapeutic efficacy and potential strategies to overcome pH-dependent therapy-resistance.

Diagnosis and treatment of in-transit melanoma metastases

In transit metastases (ITM) from extremity or trunk melanomas are subcutaneous or cutaneous lymphatic deposits of melanoma cells, distant from the primary site but not reaching the draining nodal basin. Superficial ITM metastases develop in 5-10% of melanoma patients and are thought to be caused by cells spreading along lymphatics; ITM appear biologically different from distant cutaneous metastases, these probably due to a haematogenous dissemination. The diagnosis is usually clinical and by patients, but patients need to be adequately educated in the recognition of this clinical situation. Ultrasound or more sophisticated instrumental devices may be required if the disease develops more deeply in the soft tissues. According to AJCC 2009 staging classification, ITM are included in stages IIIb and IIIc, which are considered local advanced disease with quite poor 5-year survival rates and outcomes of 24-54% at 5 years.² Loco-regional recurrence is in fact an important risk factor for distant metastatic disease, either synchronous or metachronous. Therapy for this pattern of recurrence is less standardised then in most other clinical situations and options vary based on the volume and site of the disease. Definitive surgical resection remains the preferred therapeutic approach. However, when surgery cannot be performed with a reasonable cosmetic and functional outcome, other options must be utilized.^3-6 Treatment options are classified as local, regional or systemic. The choice of therapy depends on the number of lesions, their anatomic location, whether or not these are dermal or subcutaneous, the size and the presence or absence of extra-regional disease.

Microenvironment acidity as a major determinant of tumor chemoresistance: Proton pump inhibitors (PPIs) as a novel therapeutic approach

Despite the major progresses in biomedical research and the development of novel therapeutics and treatment strategies, cancer is still among the dominant causes of death worldwide. One of the crucial challenges in the clinical management of cancer is primary (intrinsic) and secondary (acquired) resistance to both conventional and targeted chemotherapeutics. Multiple mechanisms have been identifiedthat underlie intrinsic and acquired chemoresistance: these include impaired drug uptake, increased drug efflux, deletion of receptors, altered drug metabolism, quantitative and qualitative alterations in drug targets, increased DNA damage repair and various mechanisms of anti-apoptosis. The fast efflux of anticancer drugs mediated by multidrug efflux pumps and the partial or complete reversibility of chemoresistance combined with the absence of genetic mutations suggests a multifactorial process. However, a growing body of recent evidence suggests that chemoresistance is often triggered by the highly acidic microenvironment of tumors. The vast majority of drugs, including conventional chemotherapeutics and more recent biological agents, are weak bases that are quickly protonated and neutralized in acidic environments, such as the extracellular microenvironment and the acidic organelles of tumor cells. It is therefore essential to develop new strategies to overcome the entrapment and neutralization of weak base drugs. One such strategy is the use of proton pump inhibitors which can enhance tumor chemosensitivity by increasing the pH of the tumor microenvironment. Recent clinical trials in animals with spontaneous tumors have indicated that patient alkalization is capable of reversing acquired chemoresistance in a large percentage of tumors that are refractory to chemotherapy. Of particular interest was the benefit of alkalization for patients undergoing metronomic regimens which are becoming more widely used in veterinary medicine. Overall, these results provide substantial new evidence that altering the acidic tumor microenvironment is an effective, well tolerated and low cost strategy for the overcoming of anticancer drug resistance.

Regional therapies for in-transit disease

In-transit melanoma is an uncommon pattern of recurrence, but presents unique management challenges and opportunities for treatment. The clinical presentation usually involves from 1 to more than 100 small subcutaneous or cutaneous nodules, ranging from submillimeter to multiple centimeters in diameter. Regional chemotherapy techniques are a mainstay of treatment of patients without systemic disease spread. Future applications of regional therapy are likely to involve combination therapy with cytotoxic agents and novel immune modulators. Regional therapy provides distinct opportunities for the treatment of unresectable disease, and offers a unique platform for investigation of novel therapeutics in early-stage clinical trials.

Immunotherapy following regional chemotherapy treatment of advanced extremity melanoma

PURPOSE

Following regional chemotherapy (RC) for melanoma, approximately 75 % of patients will progress. The role of immunotherapy after RC has not been well established.

METHODS

A prospective, single-institution database of 243 patients with in-transit melanoma (1995-2013) was queried for patients who had progression of disease after RC with melphalan and subsequently received systemic immunotherapy. Fifteen patients received IL-2 only, 12 received ipilimumab only, and 6 received IL-2 followed by ipilimumab. Fisher's exact test was used to determine if there was a difference in number of complete responders after immunotherapy.

RESULTS

With IL-2 alone, all patients progressed. After ipilimumab alone, three patients had a complete response and nine had progressive disease. Six additional patients received IL-2 first then ipilimumab. All six progressed on IL-2 but three went on to have a complete response to ipilimumab while three progressed. The use of ipilimumab at any time in patients who progressed after RC was associated with higher rate of complete response compared to use of IL-2 alone (33 vs. 0 %; p = 0.021).

CONCLUSIONS

Patients with progression after regional therapy for melanoma may benefit from immunologic therapy. In this group of patients, immune checkpoint blockade with ipilimumab has a higher complete response rate than T cell stimulation with IL-2, with no complete responders in the IL-2 only group. Furthermore, the complete response rate for ipilimumab in our cohort is higher than reported response rates in the literature for ipilimumab alone, suggesting that the effects of immunotherapy may be bolstered by previous regional treatment.

Australian multi-center experience outside of the Sydney Melanoma Unit of isolated limb infusion chemotherapy for melanoma

INTRODUCTION

Isolated limb infusion (ILI) is a minimally invasive alternative to isolated limb perfusion (ILP) for delivering high-dose regional chemotherapy to treat locally advanced limb melanoma. The current study aimed to evaluate the applicability of ILI in four Australian tertiary referral centers outside of its originating institution, the Sydney Melanoma Unit (SMU; currently known as the Melanoma Institute Australia).

METHODS

Data of 131 patients, treated between 1992 and 2008 were collectively analyzed. The ILI procedures were based on the Sydney Melanoma Unit protocol using melphalan. Response was determined using the WHO criteria and toxicity was assessed using the Wieberdink scale.

RESULTS

The median patient age was 74 years (range 28-100). Fifty-six percent were female. Overall response (OR) rate to ILI was 63% (CR 27%; PR 36%). Wieberdink toxicity grade III or higher was seen in 13%. No toxicity-related amputations occurred. Median follow-up was 24 months; median survival was 58 months. In patients with a complete response (CR), median survival was 101 months; in patients with a partial response (PR) this was 41 months (P = 0.026). On univariate analysis a younger age, lower-limb procedures and a lower Breslow thickness of the primary melanoma were associated with a favorable response. On multivariate analysis Breslow thickness and lower-limb ILI remained significant predictors for response.

CONCLUSION

In this, to date, largest multi-center study of ILI for melanoma the results are comparable to other reports and demonstrate that ILI can be widely implemented and safely applied across tertiary referral centers.

Isolated limb infusion: technical aspects

OBJECTIVE

To describe the technique of isolated limb infusion (ILI) for regional high dose chemotherapy in patients with advanced malignancies confined to a limb, as currently practiced at Melanoma Institute Australia (MIA).

BACKGROUND

ILI is progressively being used around the world but to date the reported response rates are generally lower than those reported by MIA.

DISCUSSION

This description of the ILI protocol at MIA provides details that may allow other surgeons to improve results.

Isolated limb infusion as a model to test new agents to treat metastatic melanoma

The limb model of in-transit disease can expand our understanding of treating melanoma because of the ease of obtaining tissue biopsies for correlative studies and the availability of preclinical animal models that allow validation of novel therapeutic strategies. This review will focus on regional therapy for in-transit melanoma as a platform to investigate novel therapeutic approaches to improve regional disease control, and help us develop insights to more rationally design systemic therapy trials.

Hypoxia in melanoma: using optical spectroscopy and EF5 to assess tumor oxygenation before and during regional chemotherapy for melanoma

BACKGROUND

There is increasing evidence that tumor hypoxia plays a significant role in the chemoresistance of melanoma, but to our knowledge, real-time tumor oxygenation during isolated limb infusion (ILI) has not been studied. We sought to demonstrate the feasibility of measuring real-time alterations in tissue oxygenation.

METHODS

Consecutive patients with histologically confirmed in-transit melanoma were enrolled onto a prospective single-arm pilot study and administered the hypoxia marker drug EF5. All patients were treated with ILI. Optical spectroscopy readings were obtained at three locations: two discrete target lesions and one normal skin control. Measurements were taken at 11 predefined time points during ILI.

RESULTS

A total of six patients were enrolled onto this pilot study. Intratumor and normal skin optical spectroscopy readings were found to have discrete inflection points throughout the duration of therapy, corresponding with established time points. Baseline hypoxia as measured by both optical spectroscopy and EF5 immunofluorescence was variable, but on the basis of optical spectra, tumors appeared to become more hypoxic compared to normal skin after tourniquet application. The optical hypoxia signature was variable between patients while hemoglobin absorption increased.

CONCLUSIONS

To our knowledge, this is the first use of real-time optical spectroscopy to evaluate oxygenation and perfusion within melanoma lesions during regional chemotherapy. We report our development of this new noninvasive means of assessing tumor vascular function, which has the potential to be a powerful tool for noninvasive examination of the melanoma tumor microenvironment.

Influence of extracellular pH on the cytotoxicity, cellular accumulation, and DNA interaction of novel pH-sensitive 2-aminoalcoholatoplatinum(II) complexes

Extracellular acidity is a frequent pathophysiological condition of solid tumors offering possibilities for improving the tumor selectivity of molecular therapy. This might be accomplished by prodrugs with low systemic toxicity, attaining their full antitumor potency only under acidic conditions, such as bis(2-aminoalcoholato-κ(2)N,O)platinum(II) complexes that are activated by protonation of alcoholato oxygen, resulting in cleavage of platinum-oxygen bonds. In this work, we examined whether the pH dependency of such compounds is reflected in differential biological activity in vitro. In particular, the pH dependence of cytotoxicity, cellular accumulation, DNA platination, GMP binding, effects on DNA secondary structure, cell cycle alterations, and induction of apoptosis was investigated. Enhanced cytotoxicity of five of these complexes in non-small-cell lung cancer (A549) and colon carcinoma (HT-29) cells at pH 6.0 in comparison with pH 7.4 was confirmed: 50 % growth inhibition concentrations ranged from 42 to 214 μM in A549 cells and from 35 to 87 μM in HT-29 cells at pH 7.4 and decreased at pH 6.0 to 11-50 and 7.3-25 μM, respectively. The effects induced by all five pH-sensitive compounds involve increased 5'-GMP binding, cellular accumulation, and DNA platination as well as stronger effects on DNA secondary structure at pH 6.0 than at pH 7.4. As exemplified by treatment of A549 cells with a 2-amino-4-methyl-1-pentanolato complex, induction of apoptosis is enhanced at pH 6.5. These results confirm the increased reactivity and in vitro activity of these compounds under slightly acidic conditions, encouraging further evaluation of ring-closed aminoalcoholatoplatinum(II) derivatives in solid tumors in vivo.

Preliminary studies with a new hypoxia-selective cytotoxin, KS119W, in vitro and in vivo

Agents with selective toxicity to hypoxic cells have shown promise as adjuncts to radiotherapy. Our previous studies showed that the bioreductive alkylating agent KS119 had an extremely large differential toxicity to severely hypoxic and aerobic cells in cell culture, and was effective in killing the hypoxic cells of EMT6 mouse mammary tumors in vivo. However, the limited solubility of that compound precluded its development as an anticancer drug. Here we report our initial studies with KS119W, a water-soluble analog of KS119. The cytotoxicity of KS119W to EMT6 cells in vitro was similar to that of KS119, with both agents producing only minimal cytotoxicity to aerobic cells even after intensive treatments, while producing pronounced cytotoxicity to oxygen-deficient cells. This resulted in large differentials in the toxicities to hypoxic and aerobic cells (>1,000-fold at 10 μM). Low pH had only minimal effects on the cytotoxicity of KS119W. Under hypoxic conditions, EMT6 cells transfected to express high levels of either human or mouse versions of the repair protein O(6)-alkylguanine-DNA alkyltransferase, which is also known as O(6)-methylguanine DNA-methyltransferase, were much more resistant to KS119W than parental EMT6 cells lacking O(6)-alkylguanine-DNA alkyltransferase, confirming the importance of DNA O-6-alkylation to the cytotoxicity of this agent. Studies with EMT6 tumors in BALB/c Rw mice using both tumor cell survival and tumor growth delay assays showed that KS119W was effective as an adjunct to irradiation for the treatment of solid tumors in vivo, producing additive or supra-additive effects in most combination regimens for which the interactions could be evaluated. Our findings encourage additional preclinical studies to examine further the antineoplastic effects of KS119W alone and in combination with radiation, and to examine the pharmacology and toxicology of this new bioreductive alkylating agent so that its potential for clinical use as an adjuvant to radiotherapy can be evaluated.

Minimally invasive intra-arterial regional therapy for metastatic melanoma: isolated limb infusion and percutaneous hepatic perfusion

INTRODUCTION

In-transit melanoma or melanoma presenting as unresectable liver metastases are clinical situations with limited therapeutic options. Regional intra-arterial therapies provide efficacious treatment alternatives for these patients. Through surgical techniques of vascular isolation, regional therapies deliver high-dose chemotherapy to tumor cells while minimizing systemic exposure. However, percutaneous techniques such as isolated limb infusion (ILI) and percutaneous hepatic perfusion (PHP) have been developed, which provide a minimally invasive means of obtaining vascular isolation of target organs.

AREAS COVERED

Areas covered in this review include the techniques of ILI and PHP, the chemotherapeutic agents utilized during these regional therapies and the clinical responses seen after ILI and PHP. The pharmacokinetics of regional chemotherapy utilized during ILI and PHP is also reviewed with an additional focus on novel ways to optimize drug delivery to improve response rates and attempts to define the potential systemic manifestations of regional therapeutics.

EXPERT OPINION

Unresectable hepatic and limb in-transit metastases from melanoma are very difficult to treat. Systemic chemotherapy has largely been ineffective. Both the minimally invasive, percutaneous techniques of ILI and PHP are excellent methods used to deliver extremely high-dose chemotherapy regionally to patients harboring metastatic melanoma confined to an extremity or liver, respectively. Studies, from prospectively maintained databases as well as Phase II and III trials, have shown the great efficacy of these techniques.

Drug resistance and cellular adaptation to tumor acidic pH microenvironment

Despite advances in developing novel therapeutic strategies, a major factor underlying cancer related death remains resistance to therapy. In addition to biochemical resistance, mediated by xenobiotic transporters or binding site mutations, resistance can be physiological, emerging as a consequence of the tumor's physical microenvironment. This review focuses on extracellular acidosis, an end result of high glycolytic flux and poor vascular perfusion. Low extracellular pH, pHe, forms a physiological drug barrier described by an "ion trapping" phenomenon. We describe how the acid-outside plasmalemmal pH gradient negatively impacts drug efficacy of weak base chemotherapies but is better suited for weakly acidic therapeutics. We will also explore the physiologic changes tumor cells undergo in response to extracellular acidosis which contribute to drug resistance including reduced apoptotic potential, genetic alterations, and elevated activity of a multidrug transporter, p-glycoprotein, pGP. Since low pHe is a hallmark of solid tumors, therapeutic strategies designed to overcome or exploit this condition can be developed.

Treatment of locally advanced melanoma by isolated limb infusion with cytotoxic drugs

Since its introduction in the late 1950s, isolated limb perfusion (ILP) has been the preferred treatment option for locally advanced melanoma and sarcoma confined to a limb. This treatment results in high response rates with a satisfying duration of response in both tumor types. A drawback of ILP, however, is the invasive and complex character of the procedure. Isolated limb infusion (ILI) has been designed in the early 1990s as a minimally invasive alternative to ILP. Results of this simple procedure, reported by various centers around the world, show comparable response rates for melanoma and sarcoma when compared to ILP. Due to its minimally invasive character, ILI may replace ILP in the future as the preferred treatment for these locally advanced limb tumors.

Isolated limb infusion with melphalan and actinomycin D in melanoma patients: factors predictive of acute regional toxicity

IMPORTANCE OF THE FIELD

Isolated limb infusion (ILI) is a simple, minimally invasive technique of delivering high concentrations of cytotoxic drugs to a diseased limb for achieving disease control in that limb. Recent studies have suggested that mild hyperthermic (38 degrees C) ILI might be the best initial treatment for extensively recurrent limb melanoma given its simplicity, low morbidity and a complete response rate of 30 - 40%.

AREAS COVERED IN THIS REVIEW

Since 1994 when ILI was first described by Thompson et al., the procedure has been adopted by several centres around the world; research and improvements in the technique have resulted in reduction in limb toxicity without reducing its clinical efficacy. The pharmacokinetics of melphalan and the clinical efficacy and adverse effects of ILI from various centres are summarised. Minor but possibly important differences in the ILI techniques used in different institutions may be important in improving its efficacy and reducing the toxic effects.

WHAT THE READER WILL GAIN

An understanding of the efficacy and toxicity associated with ILI with cytotoxic drugs in melanoma patients and of methods to optimise regional therapy for malignant disease in a limb.

TAKE HOME MESSAGE

ILI with mild hyperthermia (38 degrees C) is well tolerated with tumour remission rates in melanoma patients similar to those achieved by isolated limb perfusion. Mild (grade I - II) and moderate/severe (grade > or = III) limb toxicities occur in 58 - 68% and 32 - 41% of patients, respectively, but long-term morbidity is rare. A high peak and high final melphalan concentration in the infusate, the AUC of melphalan concentration in the infusate and an increased postoperative serum creatine phosphokinase concentration are factors predictive of acute regional toxicity. Drug dose adjusted for ideal body weight and gender may reduce acute toxicity following ILI. It has been suggested that the use of papaverine prior to the infusion of melphalan might increase its efficacy, but it may also increase toxicity. Large prospective studies are needed to more accurately define the perioperative factors that influence acute regional toxicity after ILI and to establish strategies to optimise clinical outcome.

Optimizing regional infusion treatment strategies for melanoma of the extremities

The incidence of malignant melanoma is increasing faster than any other cancer. In cases of recurrent melanoma confined to the extremities, hyperthermic isolated limb perfusion and isolated limb infusion provide a way to isolate the extremity and deliver a dose of chemotherapy several orders of magnitude higher than would be tolerated systemically. Although complete response rates of up to 80% for hyperthermic isolated limb perfusion and 44% for isolated limb infusion have been observed, there is still room for improvement and standardization in these two procedures in an attempt to optimize response while minimizing toxicity. Currently, new chemotherapy agents and small-molecule inhibitors are being investigated as a means of overcoming chemoresistance and improving response rates. In patients with advanced cutaneous disease confined to the extremities, evaluation of these new therapies can be very informative, as tissue acquisition at multiple treatment time points is easy owing to the superficial and multifocal nature of the disease. Through studying the biomolecular and genetic alterations in tumor tissue in response to these new therapies, genetically customized treatment regimens in which tumor resistance and sensitivity is predicted and treatment strategy is optimized before treatment begins may soon be available. Progress in regional therapy will prove not only beneficial for patients with disease confined to an extremity, but may also provide insight into developing novel treatment strategies for patients with systemic disease for whom current disease management options are poor.

Isolated limb infusion with cytotoxic agents: a simplified approach for venous access

BACKGROUND

Isolated limb infusion (ILI) of cytotoxic agents is a regional therapy for cutaneous malignancies in a single extremity. Conventional ILI technique requires retrograde catheterization of the contralateral femoral vein. A novel modified ILI technique uses an ipsilateral popliteal venous approach. The purpose of this study was to compare the performance of ILI using the 2 different approaches.

METHODS

Data from patients who underwent lower-extremity ILI at the authors' institution between October 2005 and June 2008 were retrospectively reviewed. The authors compared the 2 ILI approaches with regard to overall procedure time, fluoroscopy time, and the number of callbacks to the operating room (OR) for flow-related issues. The Student t test and Fisher exact test were used. Adverse events, including deep venous thrombosis (DVT) in the treated limb, were recorded.

RESULTS

Between October 2005 and June 2008, 67 lower-extremity ILI procedures (15 using a contralateral venous access approach and 52 using an ipsilateral venous access approach) were performed in 62 patients (28 men and 34 women aged 31-82 years). The mean fluoroscopy times for the contralateral and ipsilateral groups were 17.9 and 8.3 minutes, respectively (P = .0019). No significant difference in the overall procedure time and number of callbacks to the OR for flow-related issues between the 2 groups was identified.

CONCLUSIONS

The ipsilateral popliteal venous approach is a simplified and safe ILI technique with significantly lower overall fluoroscopy procedure times required for catheter placement and no difference in catheter-related adverse events, when compared with the conventional contralateral approach.

Isolated limb infusion: a review

Isolated limb perfusion is the preferred treatment option for locally advanced melanoma and sarcoma confined to a limb. This treatment results in high response rates with a satisfying duration of response in both tumours. A drawback of isolated limb perfusion, however, is the invasive and complex character of the procedure.Isolated limb infusion has been designed as a minimally invasive alternative to isolated limb perfusion. Treatment results of this simple technique, reported by various centres worldwide, show comparable response rates for melanoma and sarcoma. Therefore isolated limb infusion may replace isolated limb perfusion in the future as the preferred treatment option for these locally advanced limb tumours.

Isolated limb infusion for advanced soft tissue sarcoma of the extremity

BACKGROUND

Isolated limb infusion (ILI) is a minimally invasive technique for delivering high-dose regional chemotherapy. We report our experience with ILI for the treatment of soft tissue sarcoma (STS).

METHODS

From our prospective database, 21 patients with STS of the limb treated with ILI between 1994 and 2007 were identified. In all patients, a high-dose cytotoxic drug combination was used.

RESULTS

There were 14 men, and the median age was 60 years (range, 18-85 years). Eighteen patients (86%) had lower limb tumors. All patients had advanced local disease. The procedure was well tolerated. Fourteen patients (67%) received ILI before definitive surgery. The overall response rate was 90% (complete response [CR] rate 57%, partial response rate 33%). The disease-specific overall survival was 61.9% (median follow-up, 28 months). Only American Joint Committee on Cancer stage was associated with overall survival. The local recurrence rate was 42%. CR and malignant fibrous histiocytoma tumor subtype were associated with a lower local recurrence rate. A lower initial skin temperature (median 35.8 degrees C) was associated with a CR (P = .033). Patients who had a steep increase in intramuscular temperature during the procedure were more likely to have a CR (P = .055). Classification tree analysis identified patients with an initial PaO(2) of >/=194 mmHg as being more likely to have a CR. Ultimately, the overall limb salvage rate was 76%.

CONCLUSION

The outcomes after ILI are comparable to those achieved by conventional isolated limb perfusion. ILI is a minimally invasive alternative to isolated limb perfusion for patients with advanced STS of the extremity.

Therapy for Unresectable Recurrent and In-Transit Extremity Melanoma

Background

Unresectable recurrent and in-transit extremity melanoma presents a dilemma for the treating physician. While the disease is confined to the involved limb, the survival mimics that of multiple nodal metastases, with a 10-year survival rate of approximately 40%. This represents late-stage disease for which curative treatment options are limited.

Methods

To review the current treatment strategies for stage IIIB (N2c) in-transit and recurrent melanoma focusing on the options for unresectable disease, MEDLINE was searched for studies of known and experimental treatments for in-transit and recurrent extremity melanoma. Further results were obtained after review of the initial citations.

Results

For unresectable recurrences and in-transit metastases, therapies are limited to palliative (radiation), local (intratumoral injection, laser ablation and electroporation), regional (isolated limb perfusion/infusion), and systemic (chemotherapy) when local or regional techniques are not feasible.

Conclusions

In this patient population, intratumoral techniques have a limited role with current treatment regimens, but with the development of new drugs, these techniques may have more utility. If not contraindicated, regional techniques provide the greatest control and have minimal operative morbidity. Until new regimens are available, systemic therapy continues to be associated with considerable toxicity and only marginal response rates.

Isolated limb infusion for in-transit malignant melanoma of the extremity: a well-tolerated but less effective alternative to hyperthermic isolated limb perfusion

BACKGROUND

Isolated limb infusion (ILI) is a recently described minimally invasive technique developed in Australia for delivering regional chemotherapy. This study examined the efficacy and toxicity of ILI, compared to hyperthermic isolated limb perfusion (HILP), in treating extremity in-transit melanoma.

METHODS

Variables from a prospective single institution database of 120 regionally treated melanoma patients (1995-2007) were compared using chi-square analysis. This included 61 consecutive ILI treatments in 58 patients and 59 HILP treatments in 54 patients. Response was defined at 3 months using the response evaluation criteria in solid tumors (RECIST). ILI was performed using melphalan (LPAM) and dactinomycin for 30 min after limb temperature reached 37 degrees C. HILP was performed using LPAM for 60 min after limb temperature reached 38.5 degrees C.

RESULTS

For ILI (n = 61), the complete response (CR) rate was 30%, the partial response (PR) rate was 14%, and there was no response (NR) in 56% of patients. The median duration of CR was 12 months and 18% of patients experienced (grade >or=3) toxicity. HILP (n = 59) was associated with a better (P < 0.001) response rate (CR 57%, PR 31%, and NR 12%) however, more patients (32%) experienced grade >or=3 toxicity (P = 0.037). The dose of LPAM was corrected for ideal body weight (IBW) in 40 out of 61 ILI procedures, and 13 of 59 HILP procedures. This dosing modification was associated with decreased toxicity (P = 0.024) without diminishing response.

CONCLUSION

ILI was found to be a well-tolerated alternative to HILP. While ILI does not appear to be as effective as HILP, it does seem to be associated with less morbidity.

Outcomes following isolated limb infusion for melanoma. A 14-year experience

BACKGROUND

Isolated limb infusion (ILI) is a minimally invasive technique for delivering regional chemotherapy in patients with advanced and metastatic melanoma confined to a limb. It is essentially a low-flow isolated limb perfusion (ILP) performed via percutaneous catheters without oxygenation.

METHODS

From our prospective database 185 patients with advanced metastatic melanoma of the limb treated with a single ILI between 1993 and 2007 were identified. In all patients a cytotoxic drug combination of melphalan and actinomycin-D was used. Drug circulation time was 20-30 min under mild hyperthermic conditions (38-39 degrees C).

RESULTS

The majority of patients (62%) were female. Their average age was 74 years (range 29-93 years). Most patients had MD Anderson stage III disease (134/185). The overall response rate was 84% [complete response (CR) rate 38%, partial response rate 46%]. Median response duration was 13 months (22 months for patients with CR; P = 0.01). Median follow-up was 20 months and median survival was 38 months. In those patients with a CR, the median survival was 53 months (P = 0.005). CR rate and survival time decreased with increasing stage of disease. On multivariate analysis significant factors for a favorable outcome were achievement of CR, stage of disease, thickness of primary melanoma, the CO(2 )level in the isolated circuit, and a Wieberdink limb toxicity score of III (considerable erythema and edema).

CONCLUSION

The response rates and duration of response after ILI are comparable to those achieved by conventional ILP. ILI is a minimally invasive alternative to the much more complex and morbid conventional ILP technique for patients with advanced metastatic melanoma confined to a limb.

Early destruction of tumor vasculature in tumor necrosis factor-alpha-based isolated limb perfusion is responsible for tumor response

Addition of high-dose tumor necrosis factor-alpha to melphalan-based isolated limb perfusion enhances anti-tumor effects impressively. Unfortunately, the mechanism of action of tumor necrosis factor-alpha is still not fully understood. Here, we investigated the effects of tumor necrosis factor-alpha on the tumor microenvironment and on secondary immunological events during and shortly after isolated limb perfusion in soft-tissue sarcoma-bearing rats. Already during isolated limb perfusion, softening of the tumor was observed. Co-administration of tumor necrosis factor-alpha in the isolated limb perfusion with melphalan induced a six-fold enhanced drug accumulation of melphalan in the tumor compared with isolated limb perfusion with melphalan alone. In addition, directly after perfusion with tumor necrosis factor-alpha plus melphalan, over a time-frame of 30 min, vascular destruction, erythrocyte extravasation and hemorrhage was detected. Interstitial fluid pressure and pH in the tumor, however, were not altered by tumor necrosis factor-alpha and no clear immune effects, cellular infiltration or cytokine expression were observed. Taken together, these results indicate that tumor necrosis factor-alpha induces rapid damage to the tumor vascular endothelial lining resulting in augmented drug accumulation. As other important parameters were not changed (e.g. interstitial fluid pressure and pH), we speculate that the tumor vascular changes, and concurrent hemorrhage and drug accumulation are the key explanations for the observed synergistic anti-tumor response.

Isolated limb infusion with cytotoxic agent for treatment of localized refractory cutaneous T-cell lymphoma

We described a 57-yr-old male diagnosed with cutaneous T-cell lymphoma that had failed multiple treatment options, as his disease was mainly confined to one limb. We attempted a novel approach in this condition using a technique of intra-arterial limb infusion with cytotoxic agent Melphalan (ILI) which has been proven beneficial in management of localised malignant melanoma. This treatment approach was well tolerated with mild myelosuppression and moderate limb toxicity. However, a significant improvement has been noted in the affected limb. This case demonstrated the successful use of isolated limb infusion with Melphalan in the management of localised cutaneous T-cell lymphoma. However, this result needs to be confirmed and further study is recommended. We are unaware there have been similar cases reported in the literature.

Evaluation of hydrogen ion concentrations in prostates from rats and dogs using fluorescent confocal microscopy

The knowledge of intracellular spatial distribution of pH in prostates in animal models reflective of human prostate may have implications for drug development upon pH dependent drug delivery and activity. Freshly dissected prostate tissues (in vitro) or the entire prostate gland (in vivo) were loaded with fluorescent dyes and viewed using confocal microscopy. Images were initially taken in tissues perfused with RPMI-1640 medium. Calibration in situ was performed with high potassium buffers of known pH containing nigericin. Acetoxymethyl ester carboxy-SNARF-1 was visible in epithelial cells (but not stroma) in rat and dog prostates. The pH of lysosomes in prostate epithelial cells was 5.2 as determined by fluorescence of Lyso Sensor Green DND-189. A method of in situ confirmation of tissue viability was developed by a secondary loading and visualization of the BCECF fluorescent dye. Besides the direct measurement of the pH in rat and dog tissues (pH approximately 7.0), a method of pH measurement in prostate tissue (rather than in cell culture) was developed.

Reduction of intracellular pH as a strategy to enhance the pH-dependent cytotoxic effects of melphalan for human breast cancer cells

The microenvironment within solid tumors is slightly acidic, and manipulation of this extracellular acidity to cause intracellular acidification might be used to increase selective antitumor effects of some anticancer drugs. Potential mechanisms include inhibition of repair of DNA damage and inhibition of repopulation of tumor cells between successive courses of chemotherapy. Here, we evaluate the influence of extracellular pH (pHe) and of two agents that lead to intracellular acidification (cariporide and S3705) on toxicity of melphalan for two human breast cancer cell lines (MDA-MB231 and MCF7). Both the total number and number of colony-forming cells were evaluated during and after three sequential weekly drug treatments. Our results indicate the following: (a) Slow or absent repopulation after the first course of treatment that is influenced minimally by pHe. (b) Rapid repopulation after the second course of treatment that may be inhibited at low pHe. (c) Effects of low pHe following treatment with melphalan to increase cell kill. (d) Small effects of incubation in cariporide and S3705 at low pHe to increase the net cell kill after treatment with melphalan. Although these results add to evidence that manipulation of intracellular pH within the acidic environment of solid tumors can influence the effects of chemotherapy, they are too small and inconsistent to warrant clinical evaluation.

Metaiodobenzylguanidine and hyperglycemia augment tumor response to isolated limb perfusion in a rodent model of human melanoma

BACKGROUND

Perfusate acidification with dilute hydrochloric acid augments tumor response rates in a rodent model of isolated limb perfusion (ILP). This study investigates the combination of metaiodobenzylguanidine (MIBG), a mitochondrial inhibitor, and systemic hyperglycemia as a strategy to selectively acidify tumors and thereby sensitize them to ILP.

METHODS

Human melanoma xenografts were implanted into the hind limbs of athymic rats. When tumors reached 12 to 15 mm in diameter, animals were randomized to ILP with or without melphalan, with or without systemic MIBG, and hyperglycemia of 485 +/- 35 mg/dL. Intratumoral pH was measured during MIBG and glucose treatment by using magnetic resonance spectroscopy.

RESULTS

MIBG at 30 mg/kg plus hyperglycemia decreased intracellular pH by.6 units and extracellular pH by.8 units. MIBG at 22.5 mg/kg plus hyperglycemia decreased intracellular and extracellular pH by.4 and.5 units, respectively. Tumor growth was unaffected by systemic MIBG and hyperglycemia alone. When MIBG at 30 mg/kg and hyperglycemia were combined with ILP, tumor growth was delayed for 33 days after control ILP and for 44 days after melphalan ILP. However, this dose of MIBG was complicated by a 40% mortality rate after ILP. MIBG at 22.5 mg/kg, in combination with MIBG in the perfusate, did not cause mortality and delayed tumor growth by 51 days after melphalan ILP.

CONCLUSIONS

MIBG and hyperglycemia improve tumor response rates after ILP in a rodent model of human melanoma. Selective tumor acidification with MIBG and hyperglycemia may offer added benefit to current regional perfusion strategies.

Acidosis plus melphalan induces nitric oxide-mediated tumor regression in an isolated limb perfusion human melanoma xenograft model

BACKGROUND

Isolated limb perfusion (ILP) with melphalan is an accepted treatment for intransit melanoma of the extremities. Using an ILP human melanoma xenograft model, we tested the hypothesis that acidosis augments the antitumor effect of melphalan and that nitric oxide (NO) induction mediates tumor regression.

METHODS

NIH1286 human melanoma tumor bearing athymic nude rats underwent a 10-minute ILP. Group C was perfused at physiologic pH without acid or melphalan, group M received melphalan at physiologic pH (7.2), group A received 0.2 N of HCl at pH 6.8, and group A/M received melphalan and HCl at pH 6.8. Groups 1400W + A and 1400W + A/M were injected with 1400W, a specific inhibitor of inducible NO synthase, 1 hour pre-ILP. Tumor response was followed for up to 60 days in all survival experiments. In 4 to 6 animals from groups C, M, A, and A/M, tumor NO was measured pre- and post-ILP, and tumor and thigh muscle from 2 additional animals in each group were collected at 20 minutes and 24 hours post-ILP and processed for terminal deoxynucleotidyl transferase dUTP nick end labeling staining.

RESULTS

Maximum mean reduction in tumor size after ILP in the different groups was as follows: C = 0%, M = 55%, A = 99.6% (3 of 4 complete responses), A/M = 100% (all complete responses), 1400W + A = 0%, and 1400W + A/M = 25%. Median tumor NO was 0.87 +/- 0.74 (SD) micromol/L before ILP and increased significantly (Mann-Whitney rank sum test, P <.001) after ILP (C = +6.9%, n = 4; M = +7.5%, n = 5; A = +66.0%, n = 6; A/M = +35.9%, n = 6). Also, minimal apoptotic cell death was seen in C and M, whereas A and A/M showed evidence of widespread apoptosis.

CONCLUSIONS

Acidosis enhances the antitumor effect of melphalan. NO induction appears to play a role in tumor regression.

Prognostic factors after isolated limb infusion with cytotoxic agents for melanoma

BACKGROUND

Isolated limb perfusion (ILP) with cytotoxic agents is a remarkably effective but complex technique used to treat locally recurrent and metastatic melanoma confined to a limb. Isolated limb infusion (ILI), essentially a low-flow ILP performed without oxygenation via percutaneous catheters, has been developed as a simpler alternative.

METHODS

The outcome in 135 patients treated by ILI was reviewed.

RESULTS

The overall response rate in the treated limb was 85% (complete response [CR] rate 41%, partial response rate 44%). Median response duration response was 16 months (24 months for patients with CR). Median patient survival was 34 months. In those with a CR, the median survival was 42 months. CR rate and survival time decreased with increasing disease stage. Patients aged >70 years had a better overall response than younger patients. On multivariate analysis, factors associated with an improved outcome were a lower stage of disease, a final limb temperature >37.8 degrees C, and a tourniquet time >40 minutes.

CONCLUSIONS

The frequency and duration of responses after ILI were comparable to those achieved by conventional ILP. The ILI technique is particularly useful for older patients who might not be considered suitable for conventional ILP.