FDG uptake, glucose transporter type 1, and Ki-67 expressions in non-small-cell lung cancer: correlations and prognostic values

The tumor microenvironment in non-small-cell lung cancer

The tumor microenvironment (TME) of NSCLC is heterogeneous with variable blood flow through leaky immature vessels resulting in regions of acidosis and hypoxia. Hypoxia has been documented in NSCLC directly by polarographic needle electrodes and indirectly by assessing tissue and plasma hypoxia markers. In general, elevated expression of these markers portends poorer outcomes in NSCLC. Impaired vascularity and hypoxia can lead to increased metastasis and treatment resistance. Compounds that directly target hypoxic cells such as tirapazamine have been tested in clinical trials for NSCLC with mixed results. Preclinical data, however, suggest other ways of exploiting the abnormal TME in NSCLC for therapeutic gain. The inhibition of hypoxia-inducible factor-1alpha or vascular endothelial growth factor may increase local control after radiation. Inhibitors of the epidermal growth factor receptor (EGFR)/phosphatidylinositol 3-kinase (PI3K)/Akt pathway, such as erlotinib or PI-103, may "normalize" tumor vessels, allowing for increased chemotherapy delivery or improved oxygenation and radiation response. To select patients who may respond to these therapies and to evaluate the effects of these agents, a noninvasive means of imaging the TME is critical. Presently, there are several promising modalities to image hypoxia and the tumor vasculature; these include dynamic perfusion imaging and positron emission tomography scanning with radiolabled nitroimidazoles.

Diverging prognostic impacts of hypoxic markers according to NSCLC histology

BACKGROUND

We aimed to explore the prognostic impact of the hypoxia induced factors (HIFαs) 1-2 and the metabolic HIF-regulated glucose transporter GLUT1, lactate dehydrogenase 5 (LDH5) and carbonic anhydrase IX (CAIX) in non-small cell lung cancer (NSCLC).

METHODS

Tumor and stroma tissue samples from 335 unselected patients with stage I-IIIA NSCLC were obtained and tissue microarrays constructed. Immunohistochemistry was used to evaluate expression.

RESULTS

For squamous cell carcinoma patients, high tumor cell expression of HIF1α and low stromal cell expression of HIF1α and HIF2α correlated significantly with a poor disease-specific survival (DSS) in both univariate (tumor HIF1α, P=0.001; stromal HIF1α, P=0.009; stromal HIF2α, P=0.005) and multivariate analyses (tumor HIF1α, HR=3.3, P=0.001; stromal HIF1α, HR=2.1, P=0.008; stromal HIF2α, HR 2.3, P=0.005). Among adenocarcinoma patients high tumor expression of GLUT1 and low stromal expression of LDH5 correlated significantly with a poor DSS in both univariate (GLUT1, P=0.01; LDH5, P=0.03) and multivariate analyses (GLUT1, HR=1.9, P=0.046; LDH5, HR=2.3, P=0.03).

CONCLUSION

These markers show highly diverging prognostic impacts between histological subgroups and between tumor and stromal compartments in NSCLC.

[What is the role of FDG-PET in thoracic oncology in 2010?]

18F-Fluorodeoxyglucose-Positron Emission Tomography (FGD-PET) has been considered to have a major impact on the management of lung malignancies since the beginning of this century. Its value has been demonstrated by many publications, meta-analysis and European/American/Japanese recommendations. PET combined with computed tomography has provided useful information regarding the diagnosis and staging of lung cancer and allows for the delivery of adaptive radiotherapy. In its more common uses, PET has been shown to be cost-effective. With the widespread use of new radiotracers, PET will play an increasing role in the evaluation of response to treatment.

Irradiation-dependent effects on tumor perfusion and endogenous and exogenous hypoxia markers in an A549 xenograft model

PURPOSE

Hypoxia is a major determinant of tumor radiosensitivity, and microenvironmental changes in response to ionizing radiation (IR) are often heterogenous. We analyzed IR-dependent changes in hypoxia and perfusion in A549 human lung adenocarcinoma xenografts.

MATERIALS AND METHODS

Immunohistological analysis of two exogenously added chemical hypoxic markers, pimonidazole and CCI-103F, and of the endogenous marker Glut-1 was performed time dependently after IR. Tumor vessels and apoptosis were analyzed using CD31 and caspase-3 antibodies. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and fluorescent beads (Hoechst 33342) were used to monitor vascular perfusion.

RESULTS

CCI-103F signals measuring the fraction of hypoxic areas after IR were significantly decreased by approximately 50% when compared with pimonidazole signals, representing the fraction of hypoxic areas from the same tumors before IR. Interestingly, Glut-1 signals were significantly decreased at early time point (6.5 h) after IR returning to the initial levels at 30.5 h. Vascular density showed no difference between irradiated and control groups, whereas apoptosis was significantly induced at 10.5 h post-IR. DCE-MRI indicated increased perfusion 1 h post-IR.

CONCLUSIONS

The discrepancy between the hypoxic fractions of CCI-103F and Glut-1 forces us to consider the possibility that both markers reflect different metabolic alterations of tumor microenvironment. The reliability of endogenous markers such as Glut-1 to measure reoxygenation in irradiated tumors needs further consideration. Monitoring tumor microvascular response to IR by DCE-MRI and measuring tumor volume alterations should be encouraged.

Predictive value of 18F-fluorodeoxyglucose uptake by positron emission tomography for non-small cell lung cancer patients treated with radical radiotherapy

The purpose of this study is to assess predictive value of the positron emission tomography (PET) with 18F-fluoro-deoxyglucose (FDG) for recurrence and survival after radiotherapy (RT) for non-small cell lung cancer (NSCLC). One hundred forty-nine patients underwent pretreatment PET (n = 67) or PET/computed tomography (CT) (n = 82) and definitive RT for NSCLC. We evaluated the relationship between the maximum-pixel standardized uptake value (SUV(max)) and clinical tumor features. Univariate Cox proportional hazard analysis (UVA) was used to quantify the risk for local-regional recurrence, distant metastases, and death. Multivariate Cox proportional hazard analysis (MVA) was used to assess the potential independent effect of SUV(max). In the PET group, T1 tumors showed significantly lower SUV(max) than T2, T3, and T4 tumors; in the PET/CT group, T1 tumors showed significantly lower SUV(max) than T3 and T4 tumors. A high SUV(max )was a negative factor for local-regional control (LRC) (p < 0.001), distant metastasis-free survival (DMFS) (p = 0.02), and overall survival (OS) (p = 0.001) on UVA in the PET group. However, the significance decreased to 0.05 for LRC, 0.04 for DMFS, and 0.04 for OS by MVA when tumor size was included in the analysis. A high SUV(max) was not a negative factor for LRC, DMFS, or OS on UVA and MVA in the PET/CT group. In conclusion, assessment of predictive value of SUV(max) for NSCLC requires consideration of primary tumor size, and the evidence is not sufficient to suggest that FDG uptake in a primary NSCLC provides prognostic information.

Tumor Burden Assessed by the Maximum Standardized Uptake Value and Greatest Diameter on FDG-PET Predicts Prognosis in Untreated Diffuse Large B-cell Lymphoma

PURPOSE

It is uncertain whether the tumor burden as assessed using FDG-PET has prognostic significance in newly diagnosed diffuse large B-cell lymphoma (DLBCL). The authors undertook this study to determine whether a parameter that reflects both FDG uptake magnitude and the greatest tumor diameter is a prognostic indicator in DLBCL.

MATERIALS AND METHODS

Forty-two DLBCL patients (age, 57.4 ± 15.5 years; male/female = 25/17; stage I/II/III/IV=5/17/10/10) who underwent FDG-PET before chemotherapy were enrolled. A lesion with the highest maximum standardized uptake value (MaxSUV) on the PET image was selected, and size-incorporated MaxSUV (SIMaxSUV) of mass was calculated as MaxSUV × greatest diameter (mm) on the transaxial PET image. Median follow-up duration was 20.0 months.

RESULTS

Twelve (28.6% = 12/42) patients experienced disease progression, and 10 (23.8% = 10/42) died during follow-up. Among six variables [Ann Arbor stage, %Ki-67 expression, International Prognostic Index (IPI), MaxSUV, greatest diameter, and SIMaxSUV] investigated, only SIMaxSUV was found to be a single determinant of progression-free and overall survivals by multivariate analyses (p < 0.05).

CONCLUSION

These results suggest that SIMaxSUV, a new FDG-PET parameter that incorporates FDG uptake magnitude and the greatest tumor diameter, may be a useful indicator of prognosis in untreated DLBCL.

Prognostic value of 18F-FDG uptake on positron emission tomography in patients with pathologic stage I non-small cell lung cancer

INTRODUCTION

The intensity of 18F-fluorodeoxyglucose (18F-FDG) uptake in positron emission tomography could be of prognostic significance for patients with non-small cell lung cancer (NSCLC). The aim of this retrospective study was to evaluate the prognostic value of the FDG uptake in patients with resected pathologic stage I NSCLC according to histologic types of the tumors.

METHODS

For each patient, a maximum standardized uptake value (SUVmax) and a partial volume corrected (PVC) SUVmax were calculated for the primary lesion on positron emission tomography. To find optimal cutoff values for cancer recurrences, receiver operating characteristic curves were used.

RESULTS

Among 145 study patients, the mean values of SUVmax were 7.7 in those with adenocarcinoma (n = 70) and 16.0 in those with other histologies (n = 75; p < 0.001). Furthermore, the optimal cutoff values of SUVmax to predict cancer recurrences were identified as 5.2 in patients with adenocarcinoma and 13.8 in those with other histologies. In whole patients with pathologic stage I NSCLC, SUVmax (p = 0.025), PVC SUVmax (p = 0.014), tumor size (p = 0.048), and weight loss (p = 0.041) were significantly associated with disease-free survival (DFS). Moreover, PVC SUVmax (p = 0.034) and SUVmax (p = 0.012) were significantly associated with DFS in the multivariate analyses.

CONCLUSIONS

The intensity of FDG uptake for the primary tumor was an independent prognostic factor for DFS in whole patients with pathologic stage I NSCLC. However, caution is needed for the interpretation of optimal cutoff values of SUVmax according to tumor histologies.

Imaging pharmacodynamics in oncology: the potential significance of "flares"

The clinical use of (18)F-fluorodeoxyglucose (FDG) positron emission tomography in monitoring anticancer treatment is expanding. At the same time a number of radiotracers aiming to image different aspects of tumour biology such as proliferation and apoptosis are being developed. However, the factors determining changes of radiotracer uptake parameters in response to treatment are not well understood. In many cases, cellularity may be the primary determinant of changes of FDG uptake and may confound the interpretation of metabolic changes. Early imaging assessments have in some cases showed transient increases of uptake parameters, commonly termed "flares", which are likely to be unaffected by cellularity and directly reflect pharmacodynamics at a cellular level. In this review a number of settings where molecular imaging "flares" have been described are discussed. Such changes may often be clinically informative and warrant careful study as potential predictive biomarkers.

18F-FDG uptake in lung, breast, and colon cancers: molecular biology correlates and disease characterization

It is hoped that in the not too distant future, noninvasive imaging-based molecular interrogation and characterization of tumors can improve our fundamental understanding of the dynamic biologic behavior of cancer. For example, the new dimension of diagnostic information that is provided by (18)F-FDG PET has led to improved clinical decision making and management changes in a substantial number of patients with cancer. In this context, the aim of this review is to bring together and summarize the current data on the correlation between the underlying molecular biology and the clinical observations of tumor (18)F-FDG accumulation in 3 major human cancers: lung, breast, and colon.

Association between 18F-fluoro-2-deoxy-D-glucose uptake values and tumor vitality: prognostic value of positron emission tomography in early-stage non-small cell lung cancer

INTRODUCTION

The prognostic value of quantitative 18F-fluoro-2-deoxy-D-glucose (FDG) uptake on positron emission tomography (PET) is controversial in unselected patients with non-small cell lung cancer (NSCLC). We assessed the in vivo FDG uptake, measured as maximum pixel standardized uptake value (SUVmax), in stages I and II NSCLC for its prognostic value and association with in vitro quantitative morphology of tumor vitality.

METHODS

Prospective FDG-PET data were available in 91 consecutive patients operated for pathologic stages I and II NSCLC. Quantitative morphology was performed of tumor architecture, tumor cell density and immunohistochemical biomarkers for apoptosis (caspase-3), cell proliferation (Ki-67), hypoxia (HIF-1alpha), cellular pH regulation (carbonic anhydrase IX [CAIX]), and microvessel density (CD31).

RESULTS

SUVmax >or= median and SUVmax partial volume corrected for lesion size (PVC SUVmax) >or= median were associated with an increased risk of death in univariable analysis. After correcting for stage, tumor size and age in multivariable analysis, only PVC SUVmax >or= median remained significant. The strong significant association between tumor size and SUVmax weakened after PVC, suggesting that an important amount of SUVmax can be simply explained by tumor size, which is less in case for PVC SUVmax that associates more to the tumor cell density. In multivariable logistic regression analysis, a PVC SUVmax >or= median could be explained by high Ki-67 and high-CAIX length density.

CONCLUSION

PVC SUVmax has a prognostic value in completely resected stages I and II NSCLC. A high-quantitative FDG uptake is associated with characteristics of tumor vitality such as high tumor cell density, high cell proliferation, and extracellular acidosis.

PET, CT, and MR Imaging for Assessment of Thoracic Malignancy: Structure Meets Function

Imaging of patients with thoracic malignancy usually requires a multimodality approach. Each of these modalities has its own strengths and weaknesses. CT remains central to the staging and restaging of thoracic malignancies, but has recently been complemented with [18F]-2-fluoro-2-deoxy-D-glucose(FDG)-positron emission tomography (PET) imaging to maximize its potential. Furthermore, because FDG-PET/CT is useful at all stages of the workup and treatment of these patients, this modality has taken hold in the clinical realm for evaluation of patients with thoracic malignancy and is rapidly replacing PET-only imaging. MR imaging is also occasionally used in some patients with thoracic malignancies to improve disease staging or lesion characterization. PET/MR imaging may come to be used to evaluate patients with thoracic malignancies as well.

Targeting the delivery of glycan-based paclitaxel prodrugs to cancer cells via glucose transporters

This report describes the synthesis of four novel paclitaxel based prodrugs with glycan conjugation (1-4). Glycans were conjugated using an ester or ether bond as the linker between 2'-paclitaxel and the 2'-glucose or glucuronic acid moiety. These prodrugs showed good water solubility and selective cytotoxicity against cancer cell lines, but showed reduced toxicity toward normal cell lines and cancer cell lines with low expression levels of GLUTs. The ester conjugated prodrug 1 showed the most cytotoxicity among the prodrugs examined and could be transported into cells via GLUTs. Fluorescent and confocal microscopy demonstrated that targeted cells exhibited morphological changes in tubulin and chromosomal alterations that were similar to those observed with paclitaxel treatment. Therefore, these glycan-based prodrugs may be good drug candidates for cancer therapy, and the glycan conjugation approach is an alternative method to enhance the targeted delivery of other drugs to cancer cells that overexpress GLUTs.

Clinical biomarkers for hypoxia targeting

Tumor hypoxia or a reduction of the tissue oxygen tension is a key microenvironmental factor for tumor progression and treatment resistance in solid tumors. Because hypoxic tumor cells have been demonstrated to be more resistant to ionizing radiation, hypoxia has been a focus of laboratory and clinical research in radiation therapy for many decades. It is believed that proper detection of hypoxic regions would guide treatment options and ultimately improve tumor response. To date, most clinical efforts in targeting tumor hypoxia have yielded equivocal results due to the lack of appropriate patient selection. However, with improved understanding of the molecular pathways regulated by hypoxia and the discovery of novel hypoxia markers, the prospect of targeting hypoxia has become more tangible. This chapter will focus on the development of clinical biomarkers for hypoxia targeting.

High correlations between primary tumours and loco-regional metastatic lymph nodes in non-small-cell lung cancer with respect to glucose transporter type 1-mediated 2-deoxy-2-F18-fluoro-D-glucose uptake

The purpose of the study was to investigate whether glucose transporter type 1 (Glut-1) mediated 2-deoxy-2-F18-fluoro-D-glucose (FDG) uptake of primary tumour is related to the likelihood of malignancy involvement in loco-regional lymph nodes (LNs) in 126 non-small-cell lung cancer (NSCLC) patients (M:F=103:23, age=65+/-9.7 years). Maximum standardised uptake values (maxSUV) and Glut-1 expression levels (determined by PET and immunostaining, respectively) of primary tumours and PET positive loco-regional LNs were compared. Significant correlations were found between malignant LNs and primary tumours with respect to maxSUV (r=0.6451, p<0.0001), %Glut-1 expression (r=0.8341, p<0.0001) and Glut-1 staining intensity (rho=0.827, p<0.0001). The area-under-curve value for LN differentiation using lymph node maxSUV was significantly higher in patients with a primary tumour maxSUV of >6 (AUC=0.775, p=0.0001). High correlations between the primary tumours and metastatic LNs in NSCLC with respect to the Glut-1 mediated FDG uptake may be useful for mediastinal LN discrimination by FDG-PET.

Correlation between FDG uptake and glucose transporter type 1 expression in neuroendocrine tumors of the lung

Neuroendocrine (NE) lung tumors are subdivided into the following types; typical (TC) and atypical carcinoids (AC), large cell neuroendocrine carcinoma (LCNEC), and small cell lung carcinoma (SCLC). Moreover, the determinants of the FDG uptakes of NE lung tumors have not been elucidated. Thus, the aim of the present study was to investigate the relationships between FDG uptake and glucose transporter type 1 (Glut-1) expression in these NE tumors. Tissue-proven NE lung tumor patients (n=32; age, mean+/-S.D.=67.8+/-10 years; male:female=28:4) who had undergone F-18 FDG-PET before treatment were enrolled in this study. There were 1 TC, 3 AC, 5 LCNEC, and 23 SCLC patients. FDG uptakes were quantified using maximum standardized uptake values (maxSUV). Paraffin sections of tumor tissues were immunostained using anti-Glut-1 antibody (Neomarkers, 1:50). Levels of Glut-1 expression are presented as percentages of tumor cells positively immunostained (%Glut-1). Relations between FDG uptakes and Glut-1 expression were assessed using Pearson correlation analysis. The maxSUVs of all NE lung tumors ranged from 0.6 to 29.5 (mean+/-S.D.=7.7+/-5.4) and %Glut-1 expression ranged from 0 to 100% (18+/-24%). The maxSUVs of all NE lung tumors were found to be significantly correlated with %Glut-1 expression (r=0.6471, p=0.0001). By subgroup analysis, maxSUV was also found to be significantly correlated with %Glut-1 expression in SCLC (n=23, r=0.6189, p=0.0016). FDG uptake was found to be highly correlated with Glut-1 expression in NE lung tumors. This result suggests that Glut-1 plays a crucial role in determining FDG uptake in these tumors.

Implications of standardized uptake value measurements of the primary lesions in proven cases of breast carcinoma with different degree of disease burden at diagnosis: does 2-deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography predict tumor biology?

OBJECTIVES

Tumor glycolytic activity as determined by 2-deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography (FDG-PET) imaging is an important marker of tumor biology and provides critical information about the behavior of most malignancies at different stages of the disease. This study was undertaken to determine whether the degree of FDG uptake differs between the primary breast lesions with varying disease burden at diagnosis in proven cases of breast carcinoma.

MATERIALS AND METHODS

Among 250 patients enrolled for this prospective study, 174 patients with newly diagnosed breast carcinoma at different disease stages who had undergone dual time point FDG-PET before any therapeutic or surgical interventions were considered for inclusion in this analysis. These patients prospectively underwent multimodality imaging techniques, such as magnetic resonance imaging (MRI), ultrasonography, digital mammography, computed tomography (CT), and dual time point FDG-PET, as a component of a National Institutes of Health-funded project for characterizing primary breast lesions and local-regional staging. The slice with maximum FDG uptake in the region of interest (ROI) was chosen for the first time point and the second time point images for quantitative measurement of the metabolic activity of the tracer (SUVmax1 and SUVmax2, respectively). Furthermore, the percent change in SUVmax (%DeltaSUVmax) between SUVmax1 and SUVmax2 was calculated.

RESULTS

The patient population (n=174) were divided into three groups for the purposes of this study. Sixty-four patients with primary and metastatic axillary lymphadenopathy (designated as group I) and 18 patients with both axillary and distant metastases (designated as group II) met the inclusion criteria for this analysis. The third group (group III) comprised of a population of 92 patients without any metastasis either at the lymph nodes or at distant sites. The mean SUVmax1, SUVmax2, and the %DeltaSUVmax in the early and delayed FDG-PET in group I (n=64) patients were as follows: primary lesion 4.8+/-3.9, 5.3+/-4.5, and 9.4+/-12.8%, respectively, and axillary lesions 3+/-2.6, 3+/-2.7, and 1.1+/-21.3%, respectively. Among the group II patients (n=18), the mean values of the primary lesion with regard to the SUVmax1, SUVmax2, and the %DeltaSUVmax were 7.7+/-6.2, 8.9+/-7.1, and 15.7+/-10.8%, respectively. The corresponding figures for the axillary lesions were 3.5+/-3.1, 3.7+/-3.1, and 6.3+/-20.9%, respectively, and those for the distant metastatic lesions were 3+/-1.4, 3.1+/-1.2, and 8.5+/-21.2%, respectively. The mean SUVmax1, SUVmax2, and the %DeltaSUVmax of the primary lesion of group III patients (n=92) without any metastasis were 2.9+/-2.7, 3.4+/-2.4, and 4.5+/-4.2%, respectively. Unifactorial ANOVA of the three parameters among the primary lesions of these three groups were statistically significant with regard to the mean SUVmax1 (p=0.01) and SUVmax2 (p=0.01). These values in the primary lesions were highest in group II (those with both axillary and distant metastases), followed by group I (those with only metastatic axillary adenopathy) and group III (patients without any metastasis), and could be related to the more aggressive tumor biology in group II.

CONCLUSION

The findings provide evidence that among the lesions with varying disease burden at diagnosis, the FDG uptake is highest in cases with both axillary and distant metastasis, followed by those with axillary metastasis and then by those with no metastatic disease. These provide in vivo insight into tumor biology as FDG uptake is regarded as a surrogate marker of the same.