31P magnetic resonance spectroscopy as predictor of clinical response in human extremity sarcomas treated by single dose TNF-alpha + melphalan isolated limb perfusion

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.

High-field MRS in clinical drug development

INTRODUCTION

Magnetic resonance spectroscopy (MRS) will continue to play an ever increasing role in drug discovery because MRS does readily define biomarkers for several hundreds of clinically distinct diseases. Published evidence based medicine (EBM) surveys, which generally conclude the opposite, are seriously flawed and do a disservice to the field of drug discovery.

AREAS COVERED

This article presents MRS and how it has guided several hundreds of practical human 'drug discovery' endeavors since its development. Specifically, the author looks at the process of 'reverse-translation' and its influence in the expansion of the number of preclinical drug discoveries from in vivo MRS. The author also provides a structured approach of eight criteria, including EBM acceptance, which could potentially re-open the field of MRS for productive exploration of existing and repurposed drugs and cost-effective drug-discovery.

EXPERT OPINION

MRS-guided drug discovery is poised for future expansion. The cost of clinical trials has escalated and the use of biomarkers has become increasingly useful in improving patient selection for drug trials. Clinical MRS has uncovered a treasure-trove of novel biomarkers and clinical MRS itself has become better standardized and more widely available on 'routine' clinical MRI scanners. When combined with available new MRI sequences, MRS can provide a 'one stop shop' with multiple potential outcome measures for the disease and the drug in question.

Isolated limb perfusion with TNF-alpha and melphalan in locally advanced soft tissue sarcomas of the extremities

Limb-sparing surgery has become all the more important in soft tissue sarcoma (STS) of the extremities since we learned that amputation does not improve survival of these patients. In bulky tumours, however, preoperative strategies to reduce tumour size are then required. Isolated limb perfusion (ILP) with tumour necrosis factor (TNF) has been developed as a biochemotherapeutic therapy to act both on the tumour-associated vasculature and on the tumour itself. It has shown to be a very potent treatment modality, as in early reports response rates were around 80%. Limb salvage could then be achieved in a quite similar percentage. Many confirmatory studies have been performed since, with consistent results even in patients with multiple tumours, after extensive radiotherapy or with metastatic disease, all at the cost of very limited toxicity. This chapter gives an overview of the ILP studies performed in patients with soft tissue limb sarcoma, discusses the mechanism of TNF-mediated vasculotoxic effects on tumour vasculature, and places TNF-based ILP in the multimodality treatment of these patients with extensive STS of the extremities.

Isolated limb perfusion with melphalan and TNF-alpha in the treatment of extremity sarcoma

Isolated limb perfusion (ILP) with chemotherapy alone has uniformly failed in the treatment of irresectable extremity soft tissue sarcomas. The addition of tumor necrosis factor-alpha (TNF-α) to this treatment approach contributed to a major step forward in the treatment of locally advanced extremity soft tissue sarcoma (STS). High response rates and limb salvage rates have been reported in multicenter trials, which combined ILP with TNF-α plus melphalan, which resulted in the approval of TNF-α for this indication in Europe in 1998. Subsequently a series of confirmatory single institution reports on the efficacy of the procedure have now been published. TNF-α has an early and a late effect; it enhances tumor-selective drug uptake during the perfusion and plays an essential role in the subsequent selective destruction of the tumor vasculature. These effects result in a high response rate in high-grade soft tissue sarcomas. This induction therapy thus allows for resection of tumor remnants some 3 months after ILP and thus avoidance of limb amputation. TNF-α-based ILP is a well-established treatment to avoid amputations. It represents an important example of tumor vasculatory-modulating combination therapy and should be offered in large volume tertiary referral centers.

Extracellular pH and P-31 magnetic resonance spectroscopic variables are related to outcome in canine soft tissue sarcomas treated with thermoradiotherapy

PURPOSE

The objective was to test whether tumor pH and (31)P magnetic resonance spectroscopic end points were related to treatment outcome in pet canine patients with spontaneous soft tissue sarcomas treated with thermoradiotherapy.

EXPERIMENTAL DESIGN

Forty-two dogs with evaluable (31)P magnetic resonance spectroscopic end points and pH data were included in this study. Tumor variables (grade and volume), extracellular pH (pHe), T(2) relaxation times, intracellular pH, and selected phosphometabolite ratios were examined for correlation with clinical outcome.

RESULTS

From 39 dogs, pHe was a predictor of metastasis-free survival (MFS), with hazard ratio (HR, 0.29; P = 0.005) and overall survival (OS) with (HR, 0.36; P = 0.013). Tumor volume (>19 cm(3)) was related to MFS (HR, 2.14; P = 0.04), time to local failure (HR, 3.4; P = 0.025), and OS (HR, 2.27; P = 0.03). There was no association between T(2) or intracellular pH and clinical outcome. Tumor grade (high versus low/intermediate) and phosphodiester/betaATP ratio were identified as significant predictors for MFS, with (HR, 2.66; P = 0.009) and (HR, 0.75; P = 0.027), respectively, and as predictors of OS with (HR, 2.66; P = 0.009) and (HR, 0.76; P = 0.03), respectively. The phosphodiester/phosphocreatinine ratio predicted time to local failure (HR, 1.24; P = 0.017).

CONCLUSIONS

pHe was predictive of metastasis and OS in canine spontaneous sarcomas. To our knowledge, this is the first time that pHe has been shown to be predictive of clinical outcome. The results suggest that additional studies should be considered evaluating the prognostic significance of this variable. Phospholipid resonances, related to membrane metabolism, were related to clinical outcome, confirming recent results reported in human patients with soft tissue sarcomas treated with thermoradiotherapy.

Technology insight: Utility of TNF-alpha-based isolated limb perfusion to avoid amputation of irresectable tumors of the extremities

Isolated limb perfusion (ILP) with melphalan is effective in the treatment of small multiple melanoma intransit metastases and is utilized widely for this indication. The treatment is much less effective against bulky melanoma metastases and has uniformly failed in the treatment of irresectable extremity soft tissue sarcomas. The addition of tumor-necrosis factor-alpha (TNF-alpha) to this treatment approach has changed the situation dramatically. High response rates and limb-salvage rates have been reported in multicenter trials that combined ILP with TNF-alpha plus melphalan; these trials resulted in the approval of TNF-alpha for bulky melanoma metastases and soft tissue sarcomas in Europe in 1998. Subsequently, many doctors working in European centers have been trained, and a series of confirmatory reports from single institutions have now been published regarding the efficacy of the procedure. TNF-alpha has an early and a late effect; it enhances tumor-selective drug uptake during the perfusion, and plays an essential role in the subsequent selective destruction of the tumor vasculature. These effects result in a high response rate in bulky tumors, soft tissue sarcomas, bulky melanomas, and various other tumor types. This induction therapy therefore allows tumor remnants to be resected some 3 months after ILP thus avoiding limb amputation. TNF-alpha-based ILP is a well-established treatment that aims to avoid amputations regardless of the tumor size and type. It represents an important example of combination therapy that modulates the tumor vasculature and should be offered in high-volume tertiary referral centers.

Metabolite changes in HT-29 xenograft tumors following HIF-1alpha inhibition with PX-478 as studied by MR spectroscopy in vivo and ex vivo

The hypoxia-inducible transcription factor (HIF-1alpha) plays a central role in tumor development. PX-478 is an experimental anti-cancer drug known to inhibit HIF-1alpha in experimental tumors. The purpose of this study was to identify MRS-visible metabolic biomarkers for PX-478 response prior to phase I/II clinical trials. Single-voxel in vivo localized (1)H spectra were obtained from HT-29 tumor xenografts prior and up to 24 h after treatment with a single dose of PX-478. Profiles of water-soluble and lipophilic metabolites were also examined ex vivo with both (1)H and (31)P spectroscopy for peak identification and to interrogate the underlying biochemistry of the response. The total choline (tCho) resonance was significantly decreased in vivo 12 and 24 h following treatment with PX-478 and this was confirmed with high-resolution (1)H and (31)P MRS. In non-aqueous extracts, significant reductions in cardiolipin, PtdEtn (phosphatidylethanolamine) and PtdI (phosphatidylinositol) were seen in response to PX-478. Although there were trends to a decrease in lactate (and lipid) resonances in vivo and ex vivo, these changes were not significant. This is in contrast to inhibition of in vitro glucose consumption and lactate production by PX-478 in HT-29 cells. The significant and robust change in tCho has identified this as a potential (1)H MRS-visible biomarker for drug response in vivo while high-resolution spectroscopy indicated that GPC, PC, myoI, PE, GPE, CL, PtdEtn and PtdI are potential ex vivo response biomarkers.

Imaging and Response in Soft Tissue Sarcomas

Conventional CT and MRI scans provide exquisite anatomic detail of soft tissue sarcomas but fall short of estimating the degree of tumor viability within a sarcomatous mass. Functional imaging methods that measure biologic properties within sarcomas may be better able to determine true tumor responses to chemotherapy or radiotherapy. Many different approaches to measure biologic processes have been taken and are discussed, but positron emission tomography (PET) is currently the most quantitative and developed. A response in tumor glucose uptake, determined by PET, has been shown to correlate with improved clinical outcomes in high-grade extremity soft tissue sarcomas and gastrointestinal stromal tumors. Functional imaging of soft tissue sarcomas may prove to be useful clinically, therefore further investigation is warranted.

Dynamic contrast-enhanced MR imaging in monitoring response to isolated limb perfusion in high-grade soft tissue sarcoma: initial results

The objective of this study was to evaluate whether dynamic contrast-enhanced MR imaging can determine tumor response and localize residual viable tumor after isolated limb perfusion (ILP) chemotherapy in soft tissue tumors. Twelve consecutive patients, with histologically proven high-grade soft tissue sarcoma, prospectively underwent non-enhanced MR and dynamic contrast-enhanced MR imaging before and after ILP. Tumor volume was measured on non-enhanced MR images. The temporal change of signal intensity in a region of interest on dynamic contrast-enhanced MR images was plotted against time. Start, pattern, and progression of enhancement were recorded. Histopathologic response was defined as complete response if no residual viable tumor was present, partial remission if <50% viable tumor was present, and no change if > or =50% viable tumor was present in the resection specimen. Resected specimens for correlation with histopathology were available for 10 patients; 5 patients had partial remission and 5 had no change. Volume measurements correctly predicted tumor response in 6 of 10 patients. Dynamic contrast-enhanced MR correctly predicted tumor response in 8 of 10 patients. Early rapidly progressive enhancement correlated histologically with residual viable tumor. Late and gradual, or absence of enhancement, was associated with necrosis, predominantly centrally located, or granulation tissue. These preliminary results show that dynamic contrast-enhanced MR imaging offers potential for non-invasive monitoring of response to isolated limb perfusion in soft tissue sarcomas due to identification of residual areas of viable tumor and subsequently may provide clinically useful information with regards to timing and planning of additional surgery. Further prospective studies in a larger patient population is warranted.

Current uses of isolated limb perfusion in the clinic and a model system for new strategies

Isolated limb perfusion with melphalan is the treatment of choice for multiple (small) melanoma-in-transit metastases. The use of tumour necrosis factor alpha (TNFalpha) in isolated limb perfusion is successful for treatment of locally advanced limb soft-tissue sarcomas and other large tumours; this approach can avoid the need for amputation. TNFalpha was approved in Europe after a multicentre trial in patients with locally advanced soft-tissue sarcomas, deemed unresectable by an independent review committee; the response rate to isolated limb perfusion with TNFalpha plus melphalan was 76% and the limb was saved in 71% of patients. Moreover, the trial showed the efficacy of isolated limb perfusion of TNFalpha and melphalan against various other limb-threatening tumours such as skin cancers and drug-resistant bony sarcomas. Laboratory models of isolated limb perfusion have helped to elucidate mechanisms of action and to develop new treatment modalities. They have identified TNFalpha-mediated vasculotoxic effects on the tumour vasculature and have shown that addition of TNFalpha to the perfusate results in an increase of three to six times in uptake of melphalan or doxorubicin by tumours. New vasoactive drugs and new mechanisms of action are being discovered. Moreover, isolated limb perfusion is an effective modality for gene therapy mediated by an adenoviral vector. Various clinical phase I-II studies can be expected in the next few years.

Isolated limb perfusion in the management of locally advanced extremity soft tissue sarcoma

In conclusion, ILP is an interesting and important treatment option in the management of locally advanced extremity soft tissue sarcomas. Large medical centers, dealing with referrals and an important caseload of STS patients, should develop this treatment option and have it readily available to offer patients the best chances for limb salvage. In Europe, the success of TNF-based ILP has lead to the training, accreditation, and activation of TNF-based ILP programs in over 30 cancer centers since the approval of TNF for this indication in 1999. Thus, country by country centers for referral programs are established to deal with those categories of patients that can greatly benefit from the availability and integration of this treatment option in the STS treatment programs.

31Phosphorus-magnetic resonance spectroscopy to assess histologic tumor response noninvasively after isolated limb perfusion for soft tissue tumors

BACKGROUND

In patients with unresectable soft tissue sarcoma of the extremities, isolated limb perfusion (ILP) has been reported to result in significant tumor regression enabling limb-sparing resection in the majority of patients. However, clinical tumor response as evaluated by imaging and histopathology (extent of tumor necrosis) often differ significantly. The current study was initiated to evaluate prospectively the role of 31phosphorus-magnetic resonance spectroscopy (31P-MRS) in the noninvasive assessment of histologic response in patients treated with ILP.

METHODS

Thirty-two patients with locally advanced and unresectable soft tissue tumors (sarcoma in 28 patients and bulky melanoma in 4 patients) were treated by ILP with recombinant human tumor necrosis factor-alpha and melphalan or with cytostatics. 31P-MRS was performed prior to treatment and at regular intervals after ILP until definite tumor resection. Clinical response parameters according to the World Health Organization as well as the histopathologic necrosis rate of the resection specimen were correlated with changes in the energy-rich phosphorous metabolites phosphocreatine (PCR); alpha-, beta-, gamma-adenosine triphosphate (ATP); phosphomonoesters (PME); and inorganic phosphate (Pi).

RESULTS

Clinically, 15 of 32 patients (response rate [RR] of 47%) demonstrated a partial response (PR). The ratios of PME/PCR and PME/beta-ATP decreased significantly after ILP in comparison with preoperative values (P < 0.001). The changes in the PME/beta-ATP ratio were significantly different between clinical responders and nonresponders (P < 0.02) in contrast with the PME/PCR ratios (P < 0.09). Histologic necrosis of > 90% (pathologic (p) PR) was present in 17 resection specimens, 7 of which demonstrated no clinical response. Seven tumors demonstrated a pathologic complete response (pCR). When combining PR, pPR, and pCR (RR of 68%), 31P-MRS was able to predict response with a specificity of 94% and a sensitivity of 68% (P < 0.006, by the chi-square test).

CONCLUSIONS

The considerable difference between clinical and pathologic RR after ILP underlines the shortcomings of established response criteria. Utilizing changes in PME/beta-ATP ratios, 31P-MRS is a highly specific tool with which to predict histologic response in this setting. This finding may be of major value in those patients in whom the decision to perform a major resection or amputation must be made for local tumor control.

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

Isolated limb perfusion (ILP) with melphalan is effective against melanoma in-transit metastases but has failed in the treatment of limb-threatening extremity sarcomas. Tumor necrosis factor-alpha (TNF) has changed this situation completely. Now, ILP with TNF + melphalan is a very successful treatment to prevent amputation. In a multicenter European trial, ILP with TNF + melphalan resulted in a 76% response rate and a 71% limb salvage rate in patients with limb-threatening soft-tissue sarcomas, deemed unresectable by independent review committees, leading to approval of TNF in Europe. We have also reported on the success of this regimen against bulky melanomas, multifocal skin cancers, and drug-resistant bony sarcomas. High-dose TNF destructs tumor vasculature, and, most importantly, it enhances tumor-selective drug uptake (ie, melphalan and doxorubicin) by threefold to sixfold. Similar synergy is observed in well-vascularized liver metastases after isolated hepatic perfusion with TNF and melphalan. New (vasoactive) drugs and mechanisms of action and interaction with chemotherapy are in development. ILP is also a promising treatment modality for adenoviral vector-mediated gene therapy. Many clinical phase I/II evaluations in ILP are now underway.

Molecular aspects of magnetic resonance imaging and spectroscopy

Magnetic resonance imaging (MRI) is a well known diagnostic tool in radiology that produces unsurpassed images of the human body, in particular of soft tissue. However, the medical community is often not aware that MRI is an important yet limited segment of magnetic resonance (MR) or nuclear magnetic resonance (NMR) as this method is called in basic science. The tremendous morphological information of MR images sometimes conceal the fact that MR signals in general contain much more information, especially on processes on the molecular level. NMR is successfully used in physics, chemistry, and biology to explore and characterize chemical reactions, molecular conformations, biochemical pathways, solid state material, and many other applications that elucidate invisible characteristics of matter and tissue. In medical applications, knowledge of the molecular background of MRI and in particular MR spectroscopy (MRS) is an inevitable basis to understand molecular phenomenon leading to macroscopic effects visible in diagnostic images or spectra. This review shall provide the necessary background to comprehend molecular aspects of magnetic resonance applications in medicine. An introduction into the physical basics aims at an understanding of some of the molecular mechanisms without extended mathematical treatment. The MR typical terminology is explained such that reading of original MR publications could be facilitated for non-MR experts. Applications in MRI and MRS are intended to illustrate the consequences of molecular effects on images and spectra.

Measurements of human breast cancer using magnetic resonance spectroscopy: a review of clinical measurements and a report of localized 31P measurements of response to treatment

A review of the literature has shown that in human breast tumours, large signals from phosphomonoesters (PME) and phosphodiesters (PDE) are evident. In serial measurements in 19 patients with breast cancer, a decrease in PME was significantly associated with a stable or responding disease (p = 0.017), and an increase in PME was associated with disease progression. Extract studies have shown PME to comprise of phosphoethanolamine (PEth) and phosphocholine (PCho), with the PEth to PCho ratio ranging from 1.3 to 12. The PCho content of high grade tumours was found to be higher than low grade tumours. In some animal models, changes in PCho have been shown to correlate with indices of cellular proliferation, and spheroid studies have shown a decrease in PCho content in spheroids with smaller growth fractions. A serial study of 25 patients with advanced primary breast tumours undergoing hormone, chemotherapy or radiotherapy treatments, showed that in this heterogenous group there were significant changes in metabolites that were seen during the first 3 weeks (range 2-4 weeks) of treatment, that correlated with volume change over this period, employed here as a measure of response. Changes in PME (p = 0.003), total phosphate (TP) (p = 0.008) and total nucleoside tri-phosphate (TNTP) (p = 0.02) over 3 (+/-1) weeks were significantly associated with response, as were the levels of PME (p<0.001), PDE (p = 0.01), TP (p = 0.001) and TNTP (p = 0.007) at week 3 (+/-1). PME at week 3 (+/-1) was also significantly associated with the best volume response to treatment (p = 0.03). A reproducibility analysis of results from the observation of normal breast metabolism in four volunteers showed a mean coefficient of variation of 25%, after correcting for changes resulting from the menstrual cycle. Reproducibility studies in four patients with breast cancer showed a mean coefficient of variation of 33%, with the reproducibility being better in patients measured on different days (difference in TP was -6%) compared with those measured on the same day (difference in TP was -29%).

Phosphorus MR spectroscopy in the treatment of human extremity sarcomas

The application of 31P MR spectroscopy in the characterization and treatment of malignant human extremity tumors is reviewed and placed in the perspective of results obtained in murine sarcomas. Despite the now widespread acquisition of gradient localized spectral maps, the low spatial resolution that can be achieved at 1.5 or 2 T with 31P MRS, greatly limits its use in the study of tumor heterogeneity. The potential of 31P MRS is in the evaluation and monitoring of large inoperable extremity tumors. There are early spectral changes in human extremity sarcomas monitored after therapy, and recent studies have shown that the 31P MR spectra measured before treatment, and the changes in phosphate metabolites measured shortly thereafter, correlate with the clinical response after 2 or 3 months. Larger clinical studies are needed to confirm whether correlations of, for instance, pretreatment tumor pH with necrosis at resection and Pi decrease with tumor regression, can be used as a predictive test for clinical response.

Isolated limb perfusion in primary and recurrent melanoma: indications and results

In advanced melanoma of the limbs with in-transit metastasis, melphalan with isolated limb perfusion (M-ILP) produces around 50% complete remissions (CR). The combination of melphalan with tumour necrosis factor-alpha (TNFalpha) and interferon-gamma (IFNgamma) in isolated limb perfusion (TIM-ILP) gives around 80% CR. A prospective randomised phase II study compared 32 patients who received TIM-ILP with 32 patients who received TM-ILP (without IFNgamma). The overall remission rate (ORR) and the CR rate were superior with TIM-ILP as compared to TM-ILP, 100% vs. 91% and 78% vs. 69% respectively, but the differences are not significant. Given the efficacy of M-ILP on in-transit metastasis, the procedure was tested as an adjunct to surgery in high-risk (Breslow > or = 1.5 mm) primary melanoma of the limbs. Through the combined effort of the melanoma groups of the European Organization for Research and Treatment of Cancer (EORTC), the World Health Organization (WHO), and the North American Perfusion Group, 832 evaluable patients from 16 centres were entered in a phase III study. Median followup is 6.4 years. There was a trend for a longer disease-free interval after M-ILP. The difference is significant if the patients without elective lymph node dissection (ELND) are separately analysed, with a high significance in the 1.5 to 3 mm thickness subgroup. The occurrence of in-transit metastases was reduced from 6.6% to 3.3% by M-ILP. There was, however, no benefit of M-ILP in terms of survival. Prophylactic M-ILP cannot be recommended as a standard adjunct to surgery in high-risk primary limb melanoma. TIM-ILP or TM-ILP is a regional therapy with a very high regional response rate on melanoma in-transit metastasis.

Tumor necrosis factor-alpha in isolated perfusion systems in the treatment of cancer: the Rotterdam preclinical-clinical program

The clinical success of the application of tumor necrosis factor-alpha (TNFalpha) in isolated limb perfusions in patients with advanced sarcomas, melanomas and other tumors has renewed the interest in this agent as an anticancer drug. At the Rotterdam Cancer Center, we have developed an interactive preclinical-clinical TNFalpha program that explores new methods to use TNFalpha in various settings. Regional organ perfusion models were developed and the effectivity of targeting of TNFalpha to the tumor by means of systemic administration of liposomes are tested. Furthermore various drugs and mechanisms that may enhance the activity of TNFalpha are under investigation. A summary of this comprehensive program is presented here.

Tumour oxygenation assessed by polarographic needle electrodes and bioenergetic status measured by 31P magnetic resonance spectroscopy in human soft tissue tumours

The purpose of this study was to evaluate the feasibility of polarographic oxygen electrode measurements and phosphorus magnetic resonance spectroscopy (31P-MRS) in extravisceral soft tissue tumours, designated to receive preoperative radiotherapy. Pretreatment tumour oxygenation was determined in 41 cases and 31P-MRS was amenable to lesions in 34 patients. Biopsies were characterized histopathologically as 25 primary soft tissue sarcomas (STS), 2 recurrent STS, 9 benign and 5 other malignancies. Evaluation of phosphorus (31P) spectra was possible in 11 cases. The oxygenation status of normal tissue was higher than that of tumours, whereas no difference was found between oxygenation status of benign lesions and that of STS. There was substantial variation between tumours in the median pO2 and the bioenergetic status (beta-NTP/Pi). No correlation was found between tumour pO2 and volume (n = 25). Moreover, there was no correlation between beta-NTP/Pi and the median tumour pO2, the fraction of pO2 values < or =2.5 mmHg or tumour volume (n = 10), respectively. In conclusion, oxygen electrode assessment was found to be a clinically applicable and feasible technique for measuring tumour oxygenation status, whereas the success of 31P-MRS in human neoplasms was limited by a very poor resolution in the phosphorus signal that allowed analysis of 31P spectra in 11 tumours out of 34 cases.

Phosphorus-31 chemical shift imaging of metastatic tumors located in the spine region

RATIONALE AND OBJECTIVES

Phosphorus-31 magnetic resonance spectroscopy was used in 14 cases to examine metastases of known malignant tumors located in the spine region. The purpose was to test the hypothesis that tumor phosphomonoester (PME) is elevated.

METHODS

Two-dimensional chemical shift imaging was used in combination with a slice-select gradient in the third dimension to obtain true three-dimensional localization.

RESULTS

The spectral maps revealed PME signals increased up to 10 times in voxels containing contrast-enhancing metastatic spine lesions compared with adjacent areas and peripheral muscle voxels. Phosphomonoester increase was significant for all tumors combined (8.6 +/- 5.3 arbitrary units versus 2.4 +/- 0.5 and 2.2 +/- 0.8 arbitrary units in unaffected myelum and corpora; P < 0.001), though smaller than 2 standard deviations in 5 of 14 cases. The latter shared high proportions of phosphocreatine, phosphocreatine > 30% of total phosphate, indicating substantial amounts of muscle tissue included in the tumor voxels (partial volume effect).

CONCLUSIONS

Phosphorus-31 MR spectroscopy can be of value in the recognition of malignant vertebral column abnormalities. Malignant tumor is marked by drastic PME increases-fourfold to tenfold, provided that partial volume effects are small.

In vitro cytotoxic effects of tumor necrosis factor-alpha in human breast cancer cells may be associated with increased glucose consumption

Tumor necrosis factor-alpha inhibited growth of cultured MCF-7 human breast cancer cells in a dose dependent manner. Tumor necrosis factor-alpha also markedly increased glucose consumption, and its cytotoxicity was modified by glucose concentrations in the growth medium; higher glucose levels were associated with increased cell survival. However, when the cells were perfused in physiological conditions, very high levels of tumor necrosis factor-alpha (200 ng/ml) in the perfusion solution had no inhibitory effects. Moreover, tumor necrosis factor-alpha had no effects on 31P nuclear magnetic resonance spectra of the perfused cells. In the traditional growth inhibition assays, cells are incubated for several days with a drug, a situation where their metabolism is altered due to the depletion of nutrients, the accumulation of toxic waste materials and pH changes. Perfusion experiments are more relevant to in vivo conditions, and may be used for studying metabolic processes and the mechanisms of action of therapeutic agents.

Isolated limb perfusion with tumor necrosis factor and melphalan for limb salvage in 186 patients with locally advanced soft tissue extremity sarcomas. The cumulative multicenter European experience

OBJECTIVE

The objective of the study was to achieve limb salvage in patients with locally advanced soft tissue sarcomas that can only be treated by amputation or functionally mutilating surgery by performing an isolated limb perfusion (ILP) with tumor necrosis factor (TNF) + melphalan (M) as induction biochemotherapy to obtain local control and make limb-sparing surgery possible.

SUMMARY BACKGROUND DATA

To increase the number of limb-sparing resections in the treatment of locally advanced extremity soft tissue sarcoma, preoperative radiation therapy or chemotherapy or a combination of the two often are applied. The ILP with cytostatic agents alone is another option but rarely is used because of rather poor results. The efficacy of the application of TNF in ILP markedly has changed this situation.

METHODS

In 8 cancer centers, 186 patients were treated over a period of almost 4.5 years. There were 107 (57%) primary and 79 (43%) recurrent sarcomas, mostly high grade (110 grade III; 51 grade II; and 25 very large, recurrent, or multiple grade I sarcomas). The composition of this series of patients is unusual: 42 patients (23%) had multifocal primary or multiple recurrent tumors; median tumor size was very large (16 cm); 25 patients (13%) had known systemic metastases at the time of the ILP. Patients underwent a 90-minute ILP at 39 to 40 C with TNF + melphalan. The first 55 patients also received interferon-tau. A delayed marginal resection of the tumor remnant was done 2 to 4 months after ILP.

RESULTS

A major tumor response was seen in 82% of the patients rendering these large sarcomas resectable in most cases. Clinical response rates were: 33 complete response (CR) (18%), 106 partial response (PR) (57%), 42 no change (NC) (22%), and 5 progressive disease (PD) (3%). Final outcome was defined by clinical and pathologic response: 54 CR (29%), 99 PR (53%), 29 NC (16%), and 4 PD (2%). At a median follow-up of almost 2 years (22 months; range, 6-58 months), limb salvage was achieved in 82%. Regional toxicity was limited and systemic toxicity minimal to moderate, easily managed, with no toxic deaths.

CONCLUSIONS

In the setting of isolated limb perfusion, TNF is an active anticancer drug in patients. The ILP with TNF + melphalan can be performed safely in many centers and is an effective induction treatment with a high response rate that can achieve limb salvage in patients with locally advanced extremity soft tissue sarcoma.