Fluoro-deoxi-glucose uptake and angiogenesis are independent biological features in lung metastases

The prognostic value of positron emission tomography/computed tomography in pulmonary metastasectomy

Background

Although positron emission tomography/computed tomography (PET/CT) findings are prognostic in lung cancer patients, the prognostic value of PET/CT findings in patients with pulmonary metastases has neither been comprehensively investigated nor clarified. The aims of this retrospective study were to evaluate the value of PET/CT and identify novel prognostic indicators for pulmonary metastasectomy.

Methods

Between May 2004 and February 2017, 178 patients underwent PET/CT and resection of pulmonary metastases. After exclusion of patients who underwent biopsy only or duplicate cases, 142 patients were analyzed. Prognostic indicators, including PET/CT findings and outcomes were investigated.

Results

The median follow-up time was 42 months. The primary tumor site was colorectal in 76, kidney in 14, head and neck in 13, breast in 12, stomach in 8, urinary tract in 7, and other organs in 12 patients. The median maximal standardized uptake value (SUV_max) was 4.6. The optimal cut-off value, determined by receiver operating characteristic (ROC) analysis, identified the following cut-off values: disease-free interval (DFI) (12 months; SUV_max =4.5). Univariable analysis revealed that DFI ≤12 months, incomplete resection, and SUV_max ≥4.5 were significant for poor outcome. Multivariable analysis revealed incomplete resection and SUV_max ≥4.5 were significant for poor outcome. The 5-year survival rates of patients with SUV_max ≥4.5 and SUV_max <4.5 were 51.6% and 74.0%, respectively.

Conclusions

Analysis of patients undergoing pulmonary metastasectomy demonstrated that incomplete resection and an SUV_max ≥4.5 are significant prognostic indicators. PET/CT findings should be included in estimations of these patients' prognosis.

PET Scan Contribution in Chest Tumor Management: A Systematic Review for Thoracic Surgeons

Aims and background

In the 90s, the introduction of positron emission tomography (PET) represented a milestone in the staging of thoracic tumors. In the last 10 years, PET scan has been widely adopted in thoracic oncology, showing high accuracy in diagnosis and staging and with promising issues in defining prognosis. The aim of this systematic review was to focus on the results and pitfalls of PET scan use in the modern management of chest tumors.

Methods and study design.

The literature search was performed on May 2010 in PubMed, Embase, and Cochrane according to PRISMA protocol. The search was restricted to publications in English, using in the same string the word “PET” with 9 different chest tumors; results were then filtered by eliminating technical articles, focusing only on papers in which surgery was considered as a potential diagnostic or therapeutic tool. From 6600 papers initially selected, 99 manuscripts were fully analyzed.

Results

Glucose uptake is a metabolic marker useful in the diagnosis and staging of chest tumors. In lung cancer screening, standard uptake value is helpful in defining the risk of malignancy of isolated pulmonary nodules. The addition of PET scan to conventional staging increases detection of nodal and distant metastases in lung cancer, esophageal cancer and malignant mesothelioma. In thymoma, a close relationship between standard uptake value, histology, and Masaoka stage has been advocated. This link between glucose uptake and prognosis suggests that PET translates biological tumor behavior into clinically detectable findings.

Conclusions

PET scan has a crucial role in thoracic oncology due to its impact on diagnosis, staging and prognosis. PET scan expresses the biological behavior of tumors, opening interesting perspectives in chest tumor management and improving detection and stage grouping in lung cancer. It anticipates the diagnosis in long-incubating diseases such as mesothelioma and increases biological knowledge of rare diseases, such as thymoma and other mediastinal tumors.

Standardized Index of Shape (SIS): a quantitative DCE-MRI parameter to discriminate responders by non-responders after neoadjuvant therapy in LARC

OBJECTIVES

To investigate the potential of DCE-MRI to discriminate responders from non-responders after neoadjuvant chemo-radiotherapy (CRT) for locally advanced rectal cancer (LARC). We investigated several shape parameters for the time-intensity curve (TIC) in order to identify the best combination of parameters between two linear parameter classifiers.

METHODS

Seventy-four consecutive patients with LARC were enrolled in a prospective study approved by our ethics committee. Each patient gave written informed consent. After surgery, pathological TNM and tumour regression grade (TRG) were estimated. DCE-MRI semi-quantitative analysis (sqMRI) was performed to identify the best parameter or parameter combination to discriminate responders from non-responders in response monitoring to CRT. Percentage changes of TIC shape descriptors from the baseline to the presurgical scan were assessed and correlated with TRG. Receiver operating characteristic analysis and linear classifier were applied.

RESULTS

Forty-six patients (62.2%) were classified as responders, while 28 subjects (37.8%) were considered as non-responders. sqMRI reached a sensitivity of 93.5% and a specificity of 82.1% combining the percentage change in Maximum Signal Difference (ΔMSD) and Wash-out Slope (ΔWOS), the Standardized Index of Shape (SIS).

CONCLUSIONS

SIS obtains the best result in discriminating responders from non-responders after CRT in LARC, with a cut-off value of -3.0%.

KEY POINTS

• DCE-MRI shape descriptors are investigated to assess preoperative CRT response in LARC. • Identification of the best TIC shape descriptors combination through a linear classifier. • Identification of a single MRI index to predict neoadjuvant treatment response.

Non-small cell lung cancer evaluated with quantitative contrast-enhanced CT and PET-CT: net enhancement and standardized uptake values are related to tumour size and histology

Background

Personalized cancer therapy remains a challenge. In this context, we attempted to identify correlations between tumour angiogenesis, tumour metabolism and tumour cell type. To this aim, we used single=phase multidetector computed tomography (MDCT) and hybrid positron emission tomography-computed tomography (PET/CT) to determine whether net enhancement and standardized uptake value (SUVmax) were correlated with tumour size and cytology in patients affected by non-small cell lung cancer (NSCLC).

Material/Methods

Our study included 38 patients (30 men, 8 women, mean age 70) with a NSCLC measuring between 3 cm and 7 cm, using a 16-slice multidetector CT (Brilliance Philips) and with PET-CT (Biograph 16 Siemens Medical Solutions). The following lesion parameters were evaluated: maximum diameter, medium density before contrast injection (CT_pre), medium density after contrast injection (CT_{post average}), density in the most enhanced part of the lesion after contrast (CT_{post max}), net enhancement, SUVmax, age, and cytology. Correlation coefficient and p-value were computed for each pair of variables. In addition, correlations were computed for each pair of variables, and for all combinations of tumour types. We focused on subsets of data with more than 10 observations, and with correlation r>0.500 and p<0.05.

Results

A weak correlation (r=0.32; p=0.048) was found between SUVmax and tumour size; the correlation was stronger for masses larger than 31 mm (r=0.4515; p=0.0268). No other correlations were found among the variables examined.

Conclusions

Our data may have prognostic significance, and could lead to more appropriate surgical treatment and better treatment outcome.

Immunohistochemical overexpression of platelet-derived growth factor receptor-beta (PDGFR-β) is associated with PDGFRB gene copy number gain in sarcomatoid non-small-cell lung cancer

Sarcomatoid non-small cell lung cancer (NSCLC) is an uncommon histologic variant that has not been molecularly well-characterized. We conducted immunohistochemical and fluorescence in situ hybridization studies of PDGF-B/PDGFR-b on archived surgically resected specimens and showed high PDGFR-b IHC expression and gene copy number gain. Further studies are warranted to determine whether PDGFR-b is a feasible therapeutic target in this population.

INTRODUCTION

Sarcomatoid non-small cell lung cancer (NSCLC) is an uncommon histologic variant that has not been molecularly well-characterized. We hypothesized that the PDGF-B/PDGF-Rβ pathway may be dysregulated in sarcomatoid lung cancer.

METHODS

We conducted immunohistochemical (IHC) and gene copy number gain studies of PDGF-B/PDGFR-β on archived surgically resected specimens, 43 sarcomatoid NSCLCs and 42 control NSCLCs that were age, gender and stage-matched. Biomarkers were correlated to patient demographics, tumor characteristics, and survival.

RESULTS

Sarcomatoid tumors had higher PDGFR-β IHC expression than control NSCLC (median score 2.69 vs. 1.93; P < 0.0001). No difference was seen between the two groups of PDGF-B IHC expression; and neither PDGF-B nor PDGFR-β IHC levels correlated with gender, age, clinical or pathologic TNM status, or overall survival. PDGFRB gene copy number was evaluated by FISH using three ways: presence of amplification, gene copy number gain, and gene copy ratio between tumor and normal tissue. PDGFRB gene copy number gain was associated with sarcomatoid histology (P = 0.006), lower clinical and pathologic T-stage (P = 0.07, P = 0.048), and higher pathologic N-stage (P = 0.013). Sarcomatoid NSCLC patients (P = 0.006) and female patients (P = 0.03) had higher gene copy ratios above 1.83. Higher PDGFR-β IHC expression in tumor cells was associated with gene copy number gain (P = 0.021) and higher gene copy ratio status (P = 0.005).

CONCLUSION

This is the first study to demonstrate high PDGFR-β IHC expression and gene copy number gain in sarcomatoid NSCLC tumors and suggests that further studies are warranted to determine whether PDGFR-β is a feasible therapeutic target in this population.

Increased glucose metabolism by FDG-PET correlates with reduced tumor angiogenesis in oral squamous cell carcinoma

Hypoxia is known to have been related with angiogenesis and glycolysis, and may have an influence on tumor treatment effect. Because glucose utilization is higher in malignant cells than that in normal cells, dynamic glucose metabolism of tumor has been evaluated by means of [(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET). To investigate the significance of tumor vascularization in oral squamous cell carcinoma, we compared tumor angiogenesis with the FDG-PET findings. Twenty patients underwent FDG-PET. For the quantitative evaluation of FDG uptake in each tumor, the mean standardized uptake value (SUV) was calculated. Microvessel structures labeled with CD34 antigen were investigated in pretreatment biopsy specimens. Using an image analyzer, we calculated the following microvessel parameters: the ratio of the total number of microvessels (TN) to tumor area (TA), the ratio of the total microvessel perimeter (TP) to the TA, and the ratio of the tumor tissue area more than 150 μm distant from each microvessel (hypoxic ratio, %). The SUV was compared with the above parameters. Simple regression analysis revealed a statistical significance between the SUV and the TN:TA ratio (p = 0.046), as well as between the SUV and the TP:TA ratio (p = 0.0206). The SUV was found to be inversely related to the TN:TA and TP:TA ratios. Elevated glucose metabolism assessed by FDG-PET correlated with reduced vascularization. Higher glucose metabolism might therefore reflect a state of hypoxia.

Demonstrating Intertumoural Differences in Vascular-Metabolic Phenotype with Dynamic Contrast-Enhanced CT-PET

Purpose. To assess whether the differences in vascular-metabolic relationships between lymphoma masses and colorectal liver metastases predicted from previous histopathological studies can be demonstrated by dynamic contrast-enhanced CT (DCE-CT) combined with fluorodeoxyglucose positron emission tomography (FDG-PET). Methods. DCE-CT and FDG-PET studies were drawn from an imaging archive for patients with either lymphoma masses (n = 11) or hepatic metastases from colorectal cancer (CRM: n = 12). Tumour vascularity was assessed using DCE-CT measurements of perfusion. Tumour glucose metabolism was expressed as the mean FDG Standardised Uptake Value (SUV_FDG). The relationship between metabolism and vascularity in each group was assessed from SUV_FDG /perfusion ratios and Pearson correlation coefficients. Results. An SUV_FDG threshold of 3.0 was used to designate lymphoma masses as active (AL, n = 6) or inactive lymphoma (IL, n = 5). Tumour perfusion was significantly higher in AL (0.65 mL/min/mL) than CRM (0.37 mL/min/mL: P = .031) despite similar SUV_FDG (5.05 and 5.33, resp.). AL demonstrated higher perfusion values than IL (0.24 mL/min/mL: P = .006). SUV_FDG/perfusion was significantly higher in CRM (15.3 min) than IL (4.2 min, P < .01). There was no correlation between SUV_FDG and perfusion for any patient group.

Increased vascular endothelial growth factor-C expression is insufficient to induce lymphatic metastasis in human soft-tissue sarcomas

PURPOSE

Unlike carcinomas, soft-tissue sarcoma (STS) rarely exhibit lymphatic spread. Consequently, we examined expression and function of vascular endothelial growth factor (VEGF)-C and STS-associated lymphatic vessel density (LVD) components of this process.

EXPERIMENTAL DESIGN

VEGF-C and VEGF-A mRNA and VEGF-C protein expression were evaluated in STS, STS cell lines, and breast cancers (reverse transcription-PCR, quantitative reverse transcription-PCR, and ELISA). STS cell conditioned medium after VEGF-C knockdown was examined for endothelial cell proliferation and migration effects (MTS and migration assays). Paraffin-embedded human lymph node-negative and lymph node-positive STS and lymph node-negative and lymph node-positive breast cancers were examined for VEGF-C, D2-40, and CD31 expression (immunohistochemistry). LVD differences were analyzed by Wilcoxon rank-sum tests.

RESULTS

STS and breast cancer VEGF-C expression was comparable and higher than normal tissue levels. STS cells secreted functional VEGF-C: STS conditioned medium induced lymphatic endothelial cell proliferation and migration, which was abrogated by STS cell VEGF-C knockdown. STS and breast cancer intratumoral LVD was similar. STS peritumoral LVD (PT-LVD) was reduced versus breast cancer PT-LVD (P < 0.001). Significantly higher PT-LVD was observed in lymph node-positive versus lymph node-negative STS; lymphatic spreading STS subtypes also had higher LVD. STS VEGF-C expression and PT-LVD lacked correlation, and many lymph node-negative STS had high PT-LVD, suggesting complexity in this metastatic process.

CONCLUSIONS

Compared with breast cancers, STS exhibited lower PT-LVD independent of VEGF-C expression, which may underlie STS lymph node metastasis rarity. Moreover, lymphatic vessels appear necessary but not sufficient to sustain STS lymphatic spread. Examining STS "nonlymphatic" dissemination may help elucidate mechanisms of lymphatic spread, insights critically important to cancer metastasis control.

Warburg revisited: imaging tumour blood flow and metabolism

In the 1930s, Otto Warburg reported that anaerobic metabolism of glucose is a fundamental property of all tumours, even in the presence of an adequate oxygen supply. He also demonstrated a relationship between the degree of anaerobic metabolism and tumour growth rate. Today, this phenomenon forms the basis of tumour imaging with fluorodeoxyglucose positron emission tomography (FDG-PET). More recently, Folkman has demonstrated that malignant growth and survival are also dependent on tumour vascularity which is increasingly evaluated in vivo using techniques such as contrast enhanced computed tomography or magnetic resonance imaging (MRI). Although it is reasonable to hypothesise that the metabolic requirements of tumours are mirrored by alterations in tumour haemodynamics, the relationship between tumour blood flow and metabolism is in fact complex. A well-developed tumour vascular supply is required to ensure a sufficient delivery of glucose and oxygen to support the metabolism essential for tumour growth. However, an inadequate vascularisation of tumour will result in hypoxia, a factor that is known to stimulate anaerobic metabolism of glucose. Thus, the balance between tumour blood flow and metabolism will be an important indicator of the biological status of a tumour and hence the tumour's likely progression and response to treatment. This article reviews the molecular biology of tumour vascularisation and metabolism, relating these processes to currently available imaging techniques while summarising the imaging studies that have compared tumour blood flow and metabolism. The potential for vascular metabolic imaging to assess tumour aggression and sub-classify treatment response is highlighted.

18FDG uptake in oesophageal adenocarcinoma: linking biology and outcome

PURPOSE

Variable uptake of 18FDG has been noticed in positron emission tomography (PET) studies of patients with oesophageal adenocarcinoma. The aim of the present study was to investigate biological parameters involved in 18FDG uptake in oesophageal adenocarcinoma for selection of patients with increased 18FDG uptake and prediction of prognostic value of 18FDG PET.

PATIENTS AND METHODS

Preoperative PET scans were performed in 26 patients with histologically proven oesophageal adenocarcinoma. 18FDG uptake was semiquantitatively measured by SUV(BSAg. )Tumour sections were stained by immunohistochemistry for angiogenic markers (VEGF, CD31), glucose transporter-1 (Glut-1), hexokinase (HK) isoforms, for proliferation marker (Ki67), for macrophage marker (CD68) and for apoptosis marker (cleaved caspase-3). Cell densities, differentiation grade, degree of necrosis and mucus, T-stage and tumour size were assessed. In addition follow-up was analysed.

RESULTS

No association was found between 18FDG uptake and angiogenic markers. In contrast, a significant correlation was found between 18FDG uptake and Glut-1 expression. No correlations were found between 18FDG uptake and HK isoforms, Ki67 or cleaved caspase-3. Also, no correlations were found between 18FDG uptake and cell density, differentiation grade, CD68, mucus and necrosis. However, there was a significant correlation between 18FDG uptake and tumour size and between 18FDG uptake and tumour recurrence.

CONCLUSIONS

Glut-1 expression and tumour size seem parameters associated with 18FDG uptake in patients with biopsy proven oesophageal adenocarcinoma, and may be used to select oesophageal cancer patients in whom 18FDG-PET is of diagnostic value and may predict disease outcome.

18F-fluorodeoxyglucose positron emission tomography in patients with recurrent ovarian cancer: in comparison with vascularity, Ki-67, p53, and histologic grade

The aim of this study was to assess the correlation between 18F-fluorodeoxyglucose positron emission tomography (FDG PET) positivity of tumor recurrence and vascularity, Ki-67, p53, and histologic grade in patients with ovarian cancer. Nineteen patients with recurrent ovarian cancer underwent FDG PET before second-look surgery. Archival paraffin-embedded tissue materials were used to assess histologic grade including architectural pattern, mitotic activity, and nuclear pleomorphism; intratumor microvessel density (MVD); Ki-67; and p53. Univariate analysis was used to evaluate the correlation between FDG PET positivity and each biomarker. Stepwise logistic regression analysis was used to determine the best parameter to explain FDG PET positivity. MVD revealed significant positive correlation with FDG PET positivity (p=0.0341). There was no significant correlation between FDG PET positivity and Ki-67 or p53 (p=0.4040, p=0.6027). Mitotic activity yielded statistically significant positive correlations with FDG PET positivity (p=0.0448) although histologic grade revealed no positive correlation (p=1). Stepwise logistic regression analysis revealed MVD to be the strongest parameter for FDG PET positivity (OR=0.696, 95% CI 0.487-0.993, p=0.0458). In conclusion, FDG PET positivity revealed positive correlation with MVD and mitotic activity. MVD was the strongest parameter in predicting positive tumor recurrence on FDG PET.

Imaging vascular physiology to monitor cancer treatment

The primary physiological function of the vasculature is to support perfusion, the nutritive flow of blood through the tissues. Vascular physiology can be studied non-invasively in human subjects using imaging methods such as positron emission tomography (PET), magnetic resonance imaging (MRI), X-ray computed tomography (CT), and Doppler ultrasound (DU). We describe the physiological rationale for imaging vascular physiology with these methods. We review the published data on repeatability. We review the literature on 'before-and-after' studies using these methods to monitor response to treatment in human subjects, in five broad clinical settings: (1) antiangiogenic agents, (2) vascular disruptive agents, (3) conventional cytotoxic drugs, (4) radiation treatment, and (5) agents affecting drug delivery. We argue that imaging of vascular physiology offers an attractive 'functional endpoint' for clinical trials of anticancer treatment. More conventional measures of tumour response, such as size criteria and the uptake of fluorodeoxyglucose, may be insensitive to therapeutically important changes in vascular function.

Blood flow–metabolic relationships are dependent on tumour size in non-small cell lung cancer: a study using quantitative contrast-enhanced computer tomography and positron emission tomography

PURPOSE

The purpose of this study was to undertake dual assessment of tumour blood flow and glucose metabolism in non-small cell lung cancer (NSCLC) using contrast-enhanced computed tomography (CE-CT) and (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in order to assess how the relationships between these parameters vary with tumour size and stage.

METHODS

Tumour blood flow and glucose metabolism were assessed in 18 NSCLCs using quantitative CE-CT and FDG-PET respectively. Contrast enhancement and FDG uptake were both normalised to injected dose and patient weight to yield correspondingly the standardised perfusion value (SPV) and standardised uptake value (SUV). Tumour area was measured from conventional CT images.

RESULTS

The ratio of SUV to SVP and the metabolic-flow difference (SUV-SVP) correlated with tumour size (r=0.56, p=0.015 and r=0.60 and p=0.008 respectively). A metabolic-flow difference of greater than 4 was more common amongst tumours of stages III and IV (odds ratio 10.5; 95% confidence limits 0.24-32.1). A significant correlation between SUV and SPV was found only for tumours smaller than 4.5 cm2 (r=0.85, p=0.03).

CONCLUSION

Blood flow-metabolic relationships are not consistent in NSCLC but depend upon tumour size and stage. Quantitative CE-CT as an adjunct to an FDG study undertaken using integrated PET-CT offers an efficient way to augment the assessment of tumour biology with possible future application as part of clinical care.

Molecular imaging of tumor angiogenesis

The emergence of angiogenesis as an important target for cancer therapy has led to increased research aimed at understanding the mechanisms underlying the development, maintenance, and destruction of tumor vasculature. Concurrently, molecular imaging technologies have been developed and are being incorporated as integral components of biomedical research due to their ability to noninvasively monitor in vivo molecular events. With the evaluation of numerous anti-angiogenic agents in clinical trials, the adaptation and validation of molecular imaging modalities for monitoring angiogenesis is actively being pursued. The importance of selecting appropriate molecular targets in the study of angiogenesis has become increasingly complex due to the pleiotropy of vascular phenotypes. Furthermore, due to both the relatively low abundance of endothelial cells in tumor tissue and the inherent difficulties of detecting molecular events, molecular imaging of vasculature necessitates continued improvements in achieving higher sensitivity. While several studies have been published that set the groundwork for imaging angiogenesis, much has yet to be accomplished. Various tumor models and transgenic mice provide an excellent resource for developing molecular imaging technologies for the understanding of angiogenesis. This research may play a particularly crucial role in evaluating mechanism and efficacy during pre-clinical testing of anti-angiogenic drugs. Due to practical limitations, however, the implementation of angiogenesis-directed molecular imaging may not extend beyond highly specialized clinical trials. That is, imaging modalities that evaluate angiogenesis at a functional level may prove more appropriate. Despite future technical challenges, molecular imaging will become an important research and clinical tool in evaluating tumor angiogenesis.

Pleomorphic carcinomas of the lung show a selective distribution of gene products involved in cell differentiation, cell cycle control, tumor growth, and tumor cell motility: a clinicopathologic and immunohistochemical study of 31 cases

We investigated 31 cases of pleomorphic carcinomas of the lung, with a double component of neoplastic epithelial cells and of spindle and/or giant cells. To correlate the morphologic diversity of these two cell components with their immunophenotype, we evaluated the expression of several gene products involved in cell differentiation (cytokeratins, epithelial membrane antigen, carcinoembryonic antigen, vimentin, S-100 protein, smooth muscle actin, desmin), cell cycle control and apoptosis (p53, p21Waf1, p27Kip1, FHIT), tumor growth (proliferative fraction, assessed by Ki-67 antigen, and microvascular density, assessed by CD34 immunostaining), and tumor cell motility (fascin). We found the epithelial component to be significantly more immunoreactive for cytokeratins, epithelial membrane antigen, carcinoembryonic antigen, cell cycle inhibitors p21Waf1, p27Kip1 and tumor suppressor gene FHIT, whereas the sarcomatoid component, independent of tumor stage and size, was more immunoreactive for vimentin, fascin, and microvascular density. Accordingly, we suggest a model of tumorigenesis whereby the mesenchymal phenotype of pleomorphic cells is likely induced by the selective activation and segregation of several molecules involved in cell differentiation, cell cycle control, and tumor cell growth and motility. Whether pleomorphic carcinomas of the lung are tumors with a dismal prognosis still remains an unsettled issue. In our series, however, stage I pleomorphic carcinomas have the same clinical behavior as ordinary non-small cell lung cancer, and only a high proliferative index (Ki-67 labeling index >35%) is associated with a worse prognosis in these tumors.