31P NMR spectra of extremity sarcomas: diversity of metabolic profiles and changes in response to chemotherapy

Glycerophosphocholine and Glycerophosphoethanolamine Are Not the Main Sources of the In Vivo (31)P MRS Phosphodiester Signals from Healthy Fibroglandular Breast Tissue at 7 T

PURPOSE

The identification of the phosphodiester (PDE) (31)P MR signals in the healthy human breast at ultra-high field.

METHODS

In vivo (31)P MRS measurements at 7 T of the PDE signals in the breast were performed investigating the chemical shifts, the transverse- and the longitudinal relaxation times. Chemical shifts and transverse relaxation times were compared with non-ambiguous PDE signals from the liver.

RESULTS

The chemical shifts of the PDE signals are shifted -0.5 ppm with respect to glycerophosphocholine (GPC) and glycerophosphoethanolamine (GPE), and the transverse and longitudinal relaxation times for these signals are a factor 3 to 4 shorter than expected for aqueous GPC and GPE.

CONCLUSION

The available experimental evidence suggests that GPC and GPE are not the main source of the PDE signals measured in fibroglandular breast tissue at 7 T. These signals may predominantly originate from mobile phospholipids.

Childhood extracranial neoplasms: the role of imaging in drug development and clinical trials

Cancer is the leading cause of death in children older than 1 year of age and new drugs are necessary to improve outcomes. Imaging is crucial to the drug development process and assessment of therapeutic response. In adults, tumours are often assessed with CT using size criteria. Unfortunately, techniques established in adults are not necessarily applicable in children due to differing pathophysiology, ability to cooperate and increased susceptibility to ionising radiation. MRI, in particular quantitative MRI, has to date not been fully utilised in children with extracranial neoplasms. The specific challenges of imaging in children, the potential for functional imaging techniques to inform upon and their inclusion in clinical trials are discussed.

Molecular magnetic resonance imaging in cancer

The ability to identify key biomolecules and molecular changes associated with cancer malignancy and the capacity to monitor the therapeutic outcome against these targets is critically important for cancer treatment. Recent developments in molecular imaging based on magnetic resonance (MR) techniques have provided researchers and clinicians with new tools to improve most facets of cancer care. Molecular imaging is broadly described as imaging techniques used to detect molecular signature at the cellular and gene expression levels. This article reviews both established and emerging molecular MR techniques in oncology and discusses the potential of these techniques in improving the clinical cancer care. It also discusses how molecular MR, in conjunction with other structural and functional MR imaging techniques, paves the way for developing tailored treatment strategies to enhance cancer care.

Using magnetic resonance imaging and spectroscopy in cancer diagnostics and monitoring: preclinical and clinical approaches

Nuclear Magnetic Resonance (MR) based imaging has become an integrated domain in today's oncology research and clinical management of cancer patients. MR is a unique imaging modality among numerous other imaging modalities by providing access to anatomical, physiological, biochemical and molecular details of tumour with excellent spatial and temporal resolutions. In this review we will cover established and investigational MR imaging (MRI) and MR spectroscopy (MRS) techniques used for cancer imaging and demonstrate wealth of information on tumour biology and clinical applications MR techniques offer for oncology research both in preclinical and clinical settings. Emphasis is given not only to the variety of information which may be obtained but also the complementary nature of the techniques. This ability to determine tumour type, grade, invasiveness, degree of hypoxia, microvacular characteristics, and metabolite phenotype, has already profoundly transformed oncology research and patient management. It is evident from the data reviewed that MR techniques will play a key role in uncovering molecular fingerprints of cancer, developing targeted treatment strategies and assessing responsiveness to treatment for personalized patient management, thereby allowing rapid translation of imaging research conclusions into the benefit of clinical oncology.

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.

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.

Correlation of proton MR spectroscopic imaging with gleason score based on step-section pathologic analysis after radical prostatectomy

PURPOSE

To determine whether hydrogen 1 magnetic resonance (MR) spectroscopic imaging can be used to predict aggressiveness of prostate cancer.

MATERIALS AND METHODS

All patients gave informed consent according to an institutionally approved research protocol. A total of 123 patients (median age, 58 years; age range, 40-74 years) who underwent endorectal MR imaging and MR spectroscopic imaging between January 2000 and December 2002 were included. MR imaging and spectroscopy were performed by using combined pelvic phased-array and endorectal probe. Water and lipids were suppressed, and phase-encoded data were acquired with 6.2-mm resolution. Voxels in the peripheral zone were considered suspicious for cancer if (Cho + Cr)/Cit was at least two standard deviations above the normal level, where Cho represents choline-containing compounds, Cr represents creatine and phosphocreatine, and Cit represents citrate. Correlation between metabolite ratio and four Gleason score groups identified at step-section pathologic evaluation (3 + 3, 3 + 4, 4 + 3, and > or =4 + 4) was assessed with generalized estimating equations.

RESULTS

Data from 94 patients were included. Pathologic evaluation was used to identify 239 lesions. Overall sensitivity of MR spectroscopic imaging was 56% for tumor detection, increasing from 44% in lesions with Gleason score of 3 + 3 to 89% in lesions with Gleason score greater than or equal to 4 + 4. There was a trend toward increasing (Cho + Cr)/Cit with increasing Gleason score in lesions identified correctly with MR spectroscopic imaging. Tumor volume assessed with MR spectroscopic imaging increased with increasing Gleason score.

CONCLUSION

MR spectroscopic imaging measurement of prostate tumor (Cho + Cr)/Cit and tumor volume correlate with pathologic Gleason score. There is overlap between MR spectroscopic imaging parameters at various Gleason score levels, which may reflect methodologic and physiologic variations. MR spectroscopic imaging has potential in noninvasive assessment of prostate cancer aggressiveness.

Phosphorous-31 Magnetic Resonance Spectroscopy of Cervical Cancer Using Transvaginal Surface Coil

We developed a new transvaginal coil tuned for phosphorous-31 and measured its magnetic resonance spectroscopy ((31)P MRS) of uterine cervical cancer. In a 50-year-old woman with uterine cervical cancer (International Federation of Gynecology and Obstetrics [FIGO] stage IIIb), (31)P MRS with the new coil clearly differentiated the low intensity of phosphocreatinine (PCr) and high intensity of phosphomonoester (PME) in tumor from those in muscle. Results suggests that this method will be useful for assessing uterine cervical cancer.

Transition zone prostate cancer: metabolic characteristics at 1H MR spectroscopic imaging--initial results

PURPOSE

To determine whether cancers of the prostate transition zone (TZ) possess a unique metabolic pattern by which they may be identified at proton magnetic resonance (MR) spectroscopic imaging.

MATERIALS AND METHODS

Findings in 40 patients who underwent combined endorectal MR imaging and hydrogen 1 MR spectroscopic imaging before radical prostatectomy and who had TZ tumor identified subsequently at step-section pathologic analysis were retrospectively reviewed. Within this population, a subset of 16 patients whose TZ tumor had a largest diameter of 1 cm or greater and was included in the MR spectroscopic imaging excitation volume was identified. In these 16 patients, the ratios of choline-containing compounds (Cho) and creatine/phosphocreatine (Cr) to citrate (Cit) (ie, [Cho + Cr]/Cit), Cho/Cr, and Cho/Cit were compared in tumor and control tissues. The presence of only Cho and the absence of all metabolites were also assessed.

RESULTS

The mean values of (Cho + Cr)/Cit, Cho/Cr, and Cho/Cit were different between TZ cancer and control tissues (P =.001, P =.003, and P =.001, respectively; Wilcoxon signed rank test). Nine (56%) of 16 patients had at least one tumor voxel in which Cho comprised the only detectable peak, while no control voxels showed only Cho (P =.008, McNemar test). The percentage of voxels in which no metabolites were detected did not differ between tumor and control tissues (P =.134, McNemar test).

CONCLUSION

TZ cancer has a metabolic profile that is different from that of benign TZ tissue; however, the broad range of metabolite ratios observed in TZ cancer precludes the use of a single ratio to differentiate TZ cancer from benign TZ tissue.

Potential role of magnetic resonance spectroscopy in assessment of tumour response in childhood cancer

This brief review considers to what extent Magnetic Resonance Spectroscopy (MRS) can play a role in monitoring early tumour response with examples of preclinical studies and selected clinical studies in tumours of children and young adults. An early non-invasive indicator of tumour response to therapy would provide useful information regarding the effectiveness of therapy. This might be a relevant prognostic factor in new patients and in phase II studies could facilitate recommendations at an early stage as to whether to continue treatment. This review suggests that several markers and ratios are emerging as potential prognostic markers, but larger prospective studies are needed before translating this into clinical practice.

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.

Treatment planning for prostate implants using magnetic-resonance spectroscopy imaging

PURPOSE

Recent studies have demonstrated that magnetic-resonance spectroscopic imaging (MRSI) of the prostate may effectively distinguish between regions of cancer and normal prostatic epithelium. This diagnostic imaging tool takes advantage of the increased choline plus creatine versus citrate ratio found in malignant compared to normal prostate tissue. The purpose of this study is to describe a novel brachytherapy treatment-planning optimization module using an integer programming technique that will utilize biologic-based optimization. A method is described that registers MRSI to intraoperative-obtained ultrasound images and incorporates this information into a treatment-planning system to achieve dose escalation to intraprostatic tumor deposits.

METHODS

MRSI was obtained for a patient with Gleason 7 clinically localized prostate cancer. The ratios of choline plus creatine to citrate for the prostate were analyzed, and regions of high risk for malignant cells were identified. The ratios representing peaks on the MR spectrum were calculated on a spatial grid covering the prostate tissue. A procedure for mapping points of interest from the MRSI to the ultrasound images is described. An integer-programming technique is described as an optimization module to determine optimal seed distribution for permanent interstitial implantation. MRSI data are incorporated into the treatment-planning system to test the feasibility of dose escalation to positive voxels with relative sparing of surrounding normal tissues. The resultant tumor control probability (TCP) is estimated and compared to TCP for standard brachytherapy-planned implantation.

RESULTS

The proposed brachytherapy treatment-planning system is able to achieve a minimum dose of 120% of the 144 Gy prescription to the MRS positive voxels using (125)I seeds. The preset dose bounds of 100-150% to the prostate and 100-120% to the urethra were maintained. When compared to a standard plan without MRS-guided optimization, the estimated TCP for the MRS-optimized plan is superior. The enhanced TCP was more pronounced for smaller volumes of intraprostatic tumor deposits compared to estimated TCP values for larger lesions.

CONCLUSIONS

Using this brachytherapy-optimization system, we could demonstrate the feasibility of MRS-optimized dose distributions for (125)I permanent prostate implants. Based on probability estimates of anticipated improved TCP, this approach may have an impact on the ability to safely escalate dose and potentially improve outcome for patients with organ-confined but aggressive prostatic cancers. The magnitude of the TCP enhancement, and therefore the risks of ignoring the MR data, appear to be more substantial when the tumor is well localized; however, the gain achievable in TCP may depend quite considerably on the MRS tumor-detection efficiency.

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.

Correlation of lipid content and composition with liposarcoma histology and grade

BACKGROUND

The determination of sarcoma grade, histologic type, and differentiation is often pathologist dependent and requires considerable expertise.

METHODS

Lipid content and composition was analyzed in ex vivo fat, lipoma, and liposarcoma tissue samples using proton-decoupled 13C nuclear magnetic resonance (13C-NMR) spectroscopy and correlated with the histologic type and grade of liposarcoma.

RESULTS

The well-differentiated liposarcomas were found to have threefold increases in fatty acyl chain content compared with benign lipomas. The fatty acyl chain content of the dedifferentiated and pleomorphic liposarcomas was 1% of that found in lipoma and < 0.2% of that found in well-differentiated liposarcoma. The 2.1- to 2.8-fold increase in the degree of polyunsaturation in the dedifferentiated and pleomorphic liposarcomas compared with well-differentiated liposarcoma could largely be accounted for by the 2.3-fold increase in the percentage of fatty acyl chains of lipid containing linoleic acid. The dedifferentiated and pleomorphic liposarcomas contained both free fatty acids and phospholipids that were not NMR detectable in normal fat, lipoma, and well-differentiated liposarcoma.

CONCLUSION

Ex vivo 13C-NMR spectroscopy may be used to distinguish lipoma from well-differentiated, dedifferentiated, and pleomorphic liposarcoma based on changes in lipid and phospholipid metabolite profiles and may serve as adjunct to conventional light microscopy for the determination of liposarcoma histologic type and thus grade.

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.

Quantification of phosphorus metabolites in human calf muscle and soft-tissue tumours from localized MR spectra acquired using surface coils

Metabolite concentrations determined from MR spectra provide more specific information than peak area ratios. This paper presents a method of quantification that allows metabolite concentrations to be determined from in vivo 31P MR spectra acquired using a surface coil and ISIS localization. Corrections for the effects of B1 field inhomogeneity produced by surface coils are based on a measured and calibrated spatial sensitivity field map for the coil. Account is taken of imperfections in pulse performance, coil loading effects and relaxation effects, the latter making use of published metabolite relaxation times. The technique is demonstrated on model solutions. The concentrations of the main 31P metabolites in normal human calf muscle measured using this method are [PCr] = 26.9 +/- 4.1 mM; [Pi] = 3.6 +/- 1.2 mM; [NTP] = 6.8 +/- 1.8 mM. Quantification of spectra acquired from soft-tissue tumours in patients both pre- and post-treatment showed that changes in metabolite concentrations are more sensitive to metabolic changes than changes in peak area ratios.

Treatment-induced changes in 31P-MRS (magnetic resonance spectroscopy) spectra of sera from patients with acute leukemia

31P-nuclear magnetic resonance (NMR) spectra were obtained in vitro from sera of 40 healthy volunteers and 30 patients with acute leukemia (AL) at the time of diagnosis and repeated up to 2-13 times during therapy. All spectra consisted of inorganic phosphate (Pi) peak (used as a reference peak) and two peaks from phospholipids (PL): one peak due to phosphatidylethanolamine and sphingomyelin (PE + SM) and second peak due to phosphatidylcholine (PC). Prior to initiation of therapy 31P spectra of sera of patients with acute leukemia differed from spectra of sera of normal individuals. Peak intensities of the PL were low in relation to Pi. During therapy leading to remission, resonance from PL progressively increased approximately to the spectral pattern in normal sera. Contrary to that, in non-responders the intensities of the phospholipids peaks remained unchanged. Long-term follow-up 31P-MRS studies showed not only a good correlation between this 31P-MRS evolution of sera and the response to the therapy but also showed changes in phospholipids' levels in the following days during and after therapy. Moreover, correlations were found between high-density lipoprotein (HDL), cholesterol (CHOL) and low-density lipoprotein (LDL) concentrations measured by conventional techniques and peak intensities of PC and of PE + SM acquired by 31P-MRS.

In vivo 31P NMR spectroscopy of human musculoskeletal tumors as a measure of response to chemotherapy

The value of in vivo 31P NMR spectroscopy to provide indicators of response to cytostatic chemotherapy was studied in patients with malignant musculoskeletal tumors. Characteristics of untreated cancers were strong signals of PME and PDE, moderately increased Pi and low PCr. The intracellular pH was slightly alkaline. The intracellular concentration of free magnesium was 70% of that in muscle. Spectroscopic findings at different times of therapy were compared with the percentage of tumor necrosis after surgical resection in 28 patients. In follow-up studies, energy-rich phosphates declined in nonresponders, while PME, Pi and frequently PDE increased. Treatment response appeared to involve the reversal of these trends. In five responders, a biphasic pattern was observed, i.e. initially the spectrum changed into that of severely ischemic cell injury followed by a successive phase of apparent 'tumor activation'. Pretreatment levels of (PCr+Pi)/total phosphate > or = 0.35 and PCr/ alpha-NTP > or = 1.5, an accelerated increase in total low-energy phosphates/total high-energy phosphates (> or = 3.0%/day) after the initial drug application, and a long-term decrease (< or = -0.4%/day) during later therapy were highly indicative of tumor response to chemotherapy. Such spectroscopic predictors for treatment response proved to be superior to currently used indices such as tumor size.

Early detection of treatment response by diffusion-weighted 1H-NMR spectroscopy in a murine tumour in vivo

Nuclear magnetic resonance (NMR) non-invasively measures the apparent diffusion coefficient (ADC) of water, which is sensitive to the biophysical characteristics of tissue. Because anti-cancer treatment alters tumour pathophysiology, tumour ADC may be altered by treatment. In order to test this hypothesis, ADC was measured in s.c. implanted murine RIF-1 tumours before and up to 9 days after treatment with cyclophosphamide. A dose-dependent, reversible increase in tumour ADC was observed after cyclophosphamide treatment, which is consistent with an increase in the fraction of interstitial water due to treatment-induced cell death. Because tumour water ADC is increased substantially at a time when there is no change in tumour volume for a dose which produces minimal cell kill, its measurement could provide a novel means for early detection of response to anti-cancer therapy. If the changes in ADC observed in the present study are evident for commonly used anti-cancer therapies in different tumour types and specific to a therapeutic response, the approach could be broadly applicable as a response predictor since magnetic resonance imaging can be used to measure ADC in human tumours.

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

Irresectable extremity sarcomas are large (grade II/III) tumors requiring amputation of the limb for local control. Limb salvage can be achieved by isolated limb perfusion (ILP) with tumor necrosis factor alpha (TNF-alpha), interferon-gamma and melphalan. To obtain insight into the effects of single dose ILP on extremity tumors, phosphate metabolism was monitored by 31P magnetic resonance spectroscopy (MRS) using the chemical shift imaging (CSI) technique. 2D CSI was used in combination with a slice select gradient in the third dimension to obtain true 3D localization. Spectral maps obtained prior to ILP revealed reductions in phosphocreatine (PCr) level and increases in phosphomonoester (PME) and phosphodiester (PDE) in tumor compared with muscle tissue. ILP treated tumors showed highly divergent changes in Pi while PME decreased in all cases (n = 11). Tumor volume, unchanged on day 8 after ILP, was decreased by 58 +/- 29% (mean +/- SD) at 2 months. Linear regression analysis revealed correlation between the changes in tumor metabolites measured on day 8, with percent volume decrease (Pi: r = -0.88, p < 0.001) and percent necrosis at resection (PME: r = -0.79, p -0.01). Correlation between pretreatment spectra and effectiveness of ILP treatment was not found. It is concluded that a single ILP with TNF-alpha + melphalan induced changes in tumor metabolite levels (measured on day 8) that reflect treatment efficacy. 31P MRS can thus provide information facilitating the decision as to when to remove tumor (residue) and, in the case where tumor remains inoperable, whether or not to apply additional therapy.

Chemotherapy-associated changes in 31P MRS spectra of sera from patients with multiple myeloma

31P NMR spectra were obtained from sera of 22 healthy volunteers and 20 patients with multiple myeloma at the time of diagnosis and repeated up to five times during therapy. All spectra consisted of a Pi peak (used as a reference peak) and two peaks from phospholipids (PL): one peak due to phosphatidylethanolamine and sphingomyelin (PE + SM) and a second peak due to phosphatidylcholine (PC). Prior to therapy, peak intensities of the phospholipids were low relative to Pi. During therapy leading to remission, the resonance from PL progressively increased to approximate the spectral pattern seen in normal sera. By contrast, in non-responders an opposite trend was noted: the intensities of the phospholipid peaks became progressively reduced or remained unchanged. Long-term follow-up studies showed a good correlation between this 31P MRS evaluation of sera and the response of the disease to the therapy. In addition to the correlation with tumor response, our studies also show significant correlations between area, intensities of peaks of PE + SM, PC, and the concentrations of high-density lipoprotein (HDL) (correlation coefficients 0.46, 0.43, 0.59, respectively; p < 0.001). We found that the concentration of HDL in serum of patients with multiple myeloma was significantly reduced. In individuals responding to therapy HDL levels increased to the point where there were no statistically significant differences between them and healthy volunteers. In patients not responding to therapy, HDL concentration did not increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical applicability of human in vivo localized phosphorus-31 magnetic resonance spectroscopy of bone and soft tissue tumors

BACKGROUND

Magnetic resonance imaging (MRI) is of restricted value for the in vivo characterization of tumor types. The applicability of phosphorus-31 (31P) magnetic resonance spectroscopy (MRS) in the diagnosis of bone and soft tissue tumors is unknown.

METHODS

A total of 191 consecutive patients (85 females and 106 males; mean age 41 years, range 1-80) with a well-defined bone or soft tissue tumor on MRI were analyzed for additional 31P spectroscopy. Histology and/or cytology was obtained from all tumors. Because of low sensitivity of the 31P nucleus and the contamination of surrounding tissue, only large, superficially located tumors accessible to the surface coil could be accepted for MRS.

RESULTS

Twenty-one patients (11%) could be included in the study. From this remaining group only 12 studies (57%) produced spectra with well resolved phosphorus peaks and an acceptable signal-to-noise ratio. However, these spectra did not allow differentiation between the benign and malignant nature of the lesions. The other 9 studies showed spectra with poor signal intensities and/or poorly defined peaks, making tumor differentiation impossible.

CONCLUSION

Only 6% of the bone and soft tissue tumors produced well defined spectra, which implies that localized 31P MRS cannot be considered as a routine technique in the diagnostic and treatment evaluation of bone and soft tissue tumors.

Diagnostic procedures and pretreatment evaluation of soft tissue sarcomas

The diagnosis and preoperative evaluation of patients with a suspected soft tissue sarcoma involve several important considerations to ensure optimal treatment outcomes. Biopsy techniques must involve the retrieval of adequate tissue to establish the histologic diagnosis and grade of the tumor without compromising the subsequent definitive surgical resection. CT or MRI techniques represent the gold standard to evaluate the local extent of disease which is necessary to ascertain surgical resectability and/or the need for radiation therapy. CT scanning of the lungs is mandated for all patients with sarcomas to evaluate for metastatic disease and, for patients with abdominal or retroperitoneal tumors, scanning of the liver should also be included. Accurate staging of these patients will help define overall survival.

Preoperative and postoperative adjuvant combination chemotherapy for adults with high grade soft tissue sarcoma

BACKGROUND

Patients with high grade soft tissue sarcoma greater than or equal to 10 cm have a 3-year disease-free survival of approximately 30%. There is no convincing evidence, however, that postoperative adjuvant chemotherapy is beneficial. Preoperative chemotherapy has theoretical advantages over postoperative chemotherapy.

METHODS

Twenty-nine evaluable patients with primary or recurrent high grade, nonmetastatic, soft tissue sarcoma were treated with two preoperative cycles of cyclophosphamide 500 mg/m2, doxorubicin 60 mg/m2, and DTIC 1000 mg/m2 before definitive surgery and radiation. Clinical and radiologic assessment of response to chemotherapy was performed preoperatively, and the resected specimen was examined for treatment effects. Patients who did not progress during preoperative therapy were eligible to receive four additional cycles of chemotherapy. Disease-free and overall survival rates of study patients were compared with two cohorts of historic controls.

RESULTS

Although subjective changes in the firmness of some tumors were observed, only one patient met the criteria for partial response (3%, 2-sided 95% confidence interval = < 1-17%). Intratumoral hemorrhage, cystic necrosis, and liquefaction were observed regularly, and three tumors were more than 90% necrotic. Toxicity of the chemotherapy was acceptable, but patients were reluctant to receive postoperative therapy. The median time free from distant metastasis was 28 months; median survival was 35 months. These results were not superior to the experience with no chemotherapy, or with postoperative doxorubicin.

CONCLUSIONS

Adjuvant chemotherapy for patients with soft tissue sarcoma remains investigational. There is a strong rationale, however, for continued investigation of preoperative chemotherapy for high risk patients using doxorubicin and ifosfamide with colony stimulating factor support. Development of sensitive and specific methods to assess response to preoperative chemotherapy is needed.

31P changes as a measure of therapy response in human osteosarcomas implanted into nude mice

Our objective was to determine whether changes in PME and PCr/Pi can be used to predict lack of tumor response to chemotherapy in a murine model of human osteosarcoma. A chemotherapy-sensitive human osteosarcoma cell line was implanted into the flank of 22 nude mice. Cisplatin was administered to 11 of the mice 9 days postimplantation. 31P MR spectroscopy was performed pre- and post-chemotherapy in both sets of mice. Statistically significant changes in PCr/Pi occur from post-chemotherapy in the treated mice, but not in the untreated mice during the same time. Change in PME parallels changes in tumor volume. Changes in PCr/Pi predict lack of chemotherapy treatment in human osteosarcoma implanted into nude mice with a specificity of 80% and a sensitivity of 63%. The change in PCr/Pi occurs prior to any changes in volume of the tumor [corrected].

In vivo 31P MRS of experimental tumours

More than 50% of cancers fail to respond to any individual treatment and tumour follow-up after treatment plays a major role in routine therapy planning and pharmacological research. Today, MRS is the only technological approach providing non-invasive access to tumour biochemistry. Ten years ago, expectations were raised concerning 31P MRS as an exciting and promising technical approach to the study of tumours. However the expectations have not always come to fruition. How close are we now to seeing routine 31P NMR in clinical oncology? This review of the 127 published papers shows spectroscopy results in more than 150 experimental animal tumour models. These tumour/host/treatment systems provide us with a useful basis to evaluate the current state of the art, summarize the basic knowledge presently available, determine the key points underlying the present disappointment of some clinical oncologists and stimulate new basic research. The information collected concerns the discussion of the reliability of experimental models in oncology, the technical improvement of magnetic resonance technology and the monitoring of bioenergetic status, pH regulation and phospholipid metabolism in treated and untreated tumours. Recent advances (two-thirds of the papers have been published in the last 5 years) seem to provide more optimistic perspectives than those generally accepted a few years ago, in the depressing period following early pioneering work.

Studies of human tumors by MRS: a review

The literature describing 31P, 1H, 13C, 23Na and 19F MRS in vivo in human cancers is reviewed. Cancers have typical metabolic characteristics in 31P and 1H MRS including high levels of phospholipid metabolites and a cellular pH more alkaline than normal. These alone are not specific for cancer but are diagnostic in appropriate clinical settings. Some metabolic characteristics appear to be prognostic indices and correlation with treatment response is emerging as an important potentially cost-effective use of MRS in oncology. 19F MRS examines pharmacokinetics of 5-fluorouracil and by demonstrating its retention predicts response of a cancer to treatment. Current needs include improvement of diagnostic specificity by use of techniques like multivoxel MRS, proton decoupling of 31P, short echo time and fat-suppressed 1H MRS, 13C MRS direct or via 1H-observe, and statistical analysis of multiple spectral features. Trials in large populations in well defined clinical settings are needed to determine if MRS can provide independent prognostic indices useful in cancer management.