Non-small cell lung cancer: FDG PET for nodal staging in patients with stage I disease

Controversies in Mediastinal Staging for Nonsmall Cell Lung Cancer

Mediastinal lymph nodal involvement in nonsmall cell lung cancer plays a crucial role in deciding treatment strategy. Survival falls markedly with increasing involvement of mediastinal nodal stations. Hence, accurate staging of the mediastinum with lowest morbidity is of utmost importance. A wide array of invasive and noninvasive modalities that complement each other in assessing the nodes are available at our disposal. Guidelines recommend noninvasive imaging as the initial step in the staging algorithm for all tumors, followed by invasive staging. No single modality has proven to be the ideal method to stage the mediastinum when used alone. In the present decade, minimally invasive endobronchial ultrasound (EBUS) has challenged the position of surgical mediastinoscopy, which has been the gold standard, historically. However, a negative EBUS needs to be confirmed by surgical mediastinoscopy. Video-assisted mediastinoscopic lymphadenectomy has also come to the forefront in last two decades and has shown exceptional results, when performed in experienced centers. This review details the various modalities of mediastinal staging and the controversies surrounding the optimal method of staging, restaging after neoadjuvant therapy, and the most cost-effective strategy.

Accuracy of lung cancer staging in the multidisciplinary team setting

Accurate staging of lung cancer is of utmost importance in determining the stage-appropriate treatment and prognosis. Imaging tests which include contrast-enhanced computed tomography (CT) examination of the chest to include the liver and adrenal glands and 18-fluoro-2 deoxyglucose positron emission tomography (PET)/CT scan facilitate the initial tumor node metastasis (TNM) staging of the disease and provide guidance on the optimal biopsy site and biopsy method. The diagnostic and staging approach should be tailored to the individual patient according to risk, benefit, patient preferences, and available expertise. Diagnosis and staging should preferably be accomplished with a single procedure or the least number of invasive procedures if more than one is needed. Ideally, centers managing lung cancer patients should have a multidisciplinary thoracic oncology board prescribing personalized evidence-based management tailored to each individual patient. Multidisciplinary team (MDT) meetings provide a platform for key experts from various disciplines to contribute specific advice on the management of each individual patient. As assessment of mediastinal lymph node involvement is an important component of lung cancer staging, optimal mediastinal staging can be achieved with a variety of techniques that can be discussed and performed by the various specialists in the MDT. Despite a relative paucity of quality evidence that MDT contributes to improvements in lung cancer survival outcomes, this approach has evolved to become the standard of care in many centers around the world. Thoracic MDT has resulted in more focused and timely investigations for histopathologic diagnosis and disease staging which translate into earlier treatment initiation. Moreover, there is increasing evidence that MDT care facilitates and allows access to investigations that lead to improved accuracy of tumor and nodal staging. However, there is still a paucity of evidence on the accuracy of lung cancer staging in the MDT setting.

Differential diagnosis of human lung tumors using surface desorption atmospheric pressure chemical ionization imaging mass spectrometry

Differential diagnosis of human lung cancer in untreated tissue is achieved by DAPCI-MSI combined with multivariate statistical analysis.

Early detection of disease progression after palliative chemotherapy in NSCLC patients by (18)F-FDG-PET

AIM

We investigated whether 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is capable of detecting renewed disease progression earlier than computed tomography (CT) in patients with inoperable non-small cell lung cancer (NSCLC) who have undergone chemotherapy as part of a palliative treatment plan.

PATIENTS, METHODS

18 patients were studied retrospectively. Three FDG-PET/CT scans for initial and follow-up diagnostic purposes were evaluated. Palliative chemotherapy was administered between the first FDG-PET/CT scan (t0) and the second (t1), followed by a treatment-free interval between the second FDG-PET/CT scan (t1) and the third (t2). Maximum standardized uptake values (SUVmax) and largest diameters of lesions were determined for PET scans and the corresponding CTs. Lesion-based and patient-based assessments were performed, as were assessments according to RECIST/PERCIST.

RESULTS

82 lesions were identified in 18 patients. In interval t1-t2, the increase in diameter in the lesion-based evaluation was 5.0% (non-significant), while the patient-based evaluation showed a non-significant reduction of 2.8%. Considering PET, both the lesion-based and patient-based evaluations found a significant increase in SUVmax by a median of 30.4 % and 45.8 %, respectively. PERCIST criteria at time point t2 identified ten more patients with progression than did RECIST.

CONCLUSION

In patients with NSCLC, renewed progression during the treatment-free interval after palliative chemotherapy can be detected earlier with PET than with CT. Thus, FDG-PET appears to be a useful diagnostic imaging procedure regarding this aspect. Its clinical relevance should be investigated in further studies.

Staging lymph node metastases from lung cancer in the mediastinum

BACKGROUND

The presence of tumor metastases in the mediastinum is one of the most important elements in determining the optimal treatment strategy in patients with non-small cell lung cancer. This review is aimed at examining the current strategies for investigating lymph node metastases corresponding to an "N2" classification delineated by The International Staging Committee of the International Association for the Study of Lung Cancer (IASLC).

METHODS

Extensive review of the existing scientific literature related to the investigation of mediastinal lymph node metastases was undertaken in order to summarize and report current best practices.

CONCLUSIONS

N2 disease is very heterogeneous requiring multiple modalities for thorough investigation. New research is now focusing on better identifying, defining, and classifying lymph node metastases in the mediastinum. Molecular staging and sub-classifying mediastinal lymph node metastases are being actively researched in order to provide better prognostic value and to optimize treatment strategies. Non-invasive imaging, such as PET/CT and minimally invasive techniques such as endobronchial and endoscopic ultrasound guided biopsy, are now the lead investigative methods in evaluating the mediastinum for metastatic presence.

Lymphatic system: a prospective area for advanced targeting of particulate drug carriers

INTRODUCTION

The lymphatic system has a critical role in the immune system's recognition and response to disease and it is an additional circulatory system throughout the entire body. Extensive multidisciplinary investigations have been carried out in the area of lymphatic delivery, and lymphatic targeting has attracted a lot of attention for providing preferential chemotherapy and improving bioavailability of drugs that undergo hepatic first-pass metabolism.

AREAS COVERED

This review focuses on progress in the field of lymphatic therapeutics and diagnosis. Moreover, the anatomy and physiology of the lymphatic system, particulate drug carriers and different physicochemical parameters of both modified and unmodified particulate drug carriers and their effect on lymphatic targeting are addressed.

EXPERT OPINION

Particulate drug carriers have encouraged lymphatic targeting, but there are still challenges in targeting drugs and bioactives to specific sites, maintaining desired action and crossing all the physiological barriers. Lymphatic therapy using drug-encapsulated lipid carriers, especially liposomes and solid lipid nanoparticles, emerges as a new technology to provide better penetration into the lymphatics where residual disease exists. Size is the most important criteria when designing nanocarriers for targeting lymphatic vessels as the transportation of these particles into lymphatic vessels is size dependent. By increasing our understanding of lymphatic transport and uptake, and the role of lymphatics in various diseases, we can design new therapeutics for effective disease control.

Mediastinoscopy: trends and practice patterns in the United States

OBJECTIVES

Historically, mediastinoscopy has been the gold standard for the staging of lung cancer. A practice gap exists as the result of a variation in knowledge concerning current trends and practice patterns of mediastinoscopy usage. In addition, there are regional variations in practice-based learning and patient care. Lessons learned during surgeries performed on patients with lung cancer and other advances such as positron emission tomography and endobronchial ultrasound could be universally applied to improve surgeons' management of patient care. The purpose of this study was to assess contemporary practices in the staging of lung cancer.

METHODS

We queried the Society of Thoracic Surgeons National Database for data regarding mediastinoscopy usage, yield, and variation, both by year and region.

RESULTS

Cases with mediastinoscopy, as a percentage of all cases performed in the database, have significantly decreased from 14.6% in 2006 to 11.4% in 2010 (P < 0.001). The 5-year median rate of mediastinoscopy in lung cancer patients at 163 centers was 15.3% (interquartile range 5.2%-31.7%), indicating significant variation among centers. The overall median center rate also decreased over time from 21.4% (2006) to 10.0% (2010).

CONCLUSIONS

With advances in minimally invasive procedures and imaging, mediastinoscopy usage has declined significantly. Our findings are likely to be relevant to both clinical practice and practice guidelines.

Methods for staging non-small cell lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

BACKGROUND

Correctly staging lung cancer is important because the treatment options and prognosis differ significantly by stage. Several noninvasive imaging studies and invasive tests are available. Understanding the accuracy, advantages, and disadvantages of the available methods for staging non-small cell lung cancer is critical to decision-making.

METHODS

Test accuracies for the available staging studies were updated from the second iteration of the American College of Chest Physicians Lung Cancer Guidelines. Systematic searches of the MEDLINE database were performed up to June 2012 with the inclusion of selected meta-analyses, practice guidelines, and reviews. Study designs and results are summarized in evidence tables.

RESULTS

The sensitivity and specificity of CT scanning for identifying mediastinal lymph node metastasis were approximately 55% and 81%, respectively, confirming that CT scanning has limited ability either to rule in or exclude mediastinal metastasis. For PET scanning, estimates of sensitivity and specificity for identifying mediastinal metastasis were approximately 77% and 86%, respectively. These findings demonstrate that PET scanning is more accurate than CT scanning, but tissue biopsy is still required to confirm PET scan findings. The needle techniques endobronchial ultrasound-needle aspiration, endoscopic ultrasound-needle aspiration, and combined endobronchial ultrasound/endoscopic ultrasound-needle aspiration have sensitivities of approximately 89%, 89%, and 91%, respectively. In direct comparison with surgical staging, needle techniques have emerged as the best first diagnostic tools to obtain tissue. Based on randomized controlled trials, PET or PET-CT scanning is recommended for staging and to detect unsuspected metastatic disease and avoid noncurative resections.

CONCLUSIONS

Since the last iteration of the staging guidelines, PET scanning has assumed a more prominent role both in its use prior to surgery and when evaluating for metastatic disease. Minimally invasive needle techniques to stage the mediastinum have become increasingly accepted and are the tests of first choice to confirm mediastinal disease in accessible lymph node stations. If negative, these needle techniques should be followed by surgical biopsy. All abnormal scans should be confirmed by tissue biopsy (by whatever method is available) to ensure accurate staging. Evidence suggests that more complete staging improves patient outcomes.

Validation of EBUS-TBNA-integrated nodal staging in potentially node-positive non-small cell lung cancer

Objective

Nodal staging of lung cancer is important for selecting surgical candidates. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) was evaluated as a modality for nodal staging of patients with potentially node-positive non-small cell lung cancer (NSCLC).

Methods

Endobronchial ultrasound-guided transbronchial needle aspiration was used for nodal staging of NSCLC patients with radiological N2/3 disease (short axis >10 mm on computed tomography and/or standardized positron emission uptake value >2.5 on 2-deoxy-2[F-18] fluoro-d-glucose positron emission tomography), T-stage ≥ T2, or positive serum carcinoembryonic antigen. Data on eligible patients were extracted from the database of our institution and analyzed for differences in nodal stages between radiological staging (RS) and EBUS-TBNA-integrated staging (ES), with validation by pathological staging of patients who had undergone surgery.

Results

Of 480 eligible patients, there were 135 N0/1 and 345 N2/3 patients according to RS. Out of the 345 patients staged as N2/3 by RS, 113 (33 %) were downgraded to N0/1 by ES. Out of the 135 patients staged as N0/1 by RS, 12 (9 %) were upgraded to N2/3 by ES. Patients were restaged as N0/1 in 236 cases and N2/3 in 244 cases by ES, and the distributions of nodal stage between RS and ES were significantly different (p < 0.001). Finally, 215 out of the 236 ES-N0/1 patients underwent lung resection, and 195 (90.7 %) and 20 patients were staged by pathology as N0/1 and N2, respectively.

Conclusions

Endobronchial ultrasound-guided transbronchial needle aspiration is more accurate for lymph node staging compared to radiological staging. EBUS-TBNA can identify patients who are true candidates for surgery.

Preoperative serum value of sialyl Lewis X predicts pathological nodal extension and survival in patients with surgically treated small cell lung cancer

BACKGROUND AND OBJECTIVES

We investigated various tumor markers in patients with surgically treated small cell lung cancer (SCLC) to identify the markers closely correlated to pathological staging and to predict survival by retrospective analyses.

METHODS

Reviewing database records between 1990 and 2007 revealed 36 patients with SCLC, that were grouped according to clinical and pathological stages. Receiver operating characteristic (ROC) curves were calculated for serum levels of various tumor makers to predict the pathological stage. The cut-off value was calculated from the ROC curve of the significant marker. Survival in patient groups divided by the new cut-off value was calculated.

RESULTS

Serum levels of various tumor makers were not significantly different between the pathological stage groups, except for serum sialyl Lewis X (SLX). ROC curve of SLX was significantly correlated to pathological stages (P = 0.0136). The calculated SLX cut-off value was 25.1 U/ml, with 80% sensitivity and 70% specificity. Five-year survival of patients selected by this new cut-off was 82.5%, whereas that with the standard cut-off (38.0 U/ml) was 55.9%.

CONCLUSIONS

Serum SLX values were associated with pathological stage and survival after surgery in SCLC patients.

Mediastinal lymph nodes staging by 18F-FDG PET/CT for early stage non-small cell lung cancer: a multicenter study

PURPOSE

Accurate staging of mediastinal lymph nodes metastases is critical for determining the application of stereotactic body radiation therapy (SBRT) for patients with early stage non-small cell lung cancer (NSCLC). In this multicenter study the accuracy of (18)F-FDG PET/CT to detect lymph node metastases was evaluated for early stage NSCLC.

MATERIALS AND METHODS

The data from the patients with stage1 NSCLC who received preoperative (18)F-FDG PET/CT staging and radical surgery was retrospectively reviewed of five centers from February 2004 to August 2010. The lymph node metastases were confirmed histopathologically after radical surgery. And the sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were calculated for PET/CT staging.

RESULTS

Two hundred patients were enrolled. The sensitivity, specificity, accuracy, PPV and NPV for lymph node metastases on PET/CT were 44%, 83%, 78%, 29% and 91%, respectively. There were eight and 19 cases positive for lymph node metastases with central (n=62) and peripheral (n=138) NSCLC (P>0.05), respectively.

CONCLUSION

(18)F-FDG PET/CT was specific in N(0) staging for T(1-2) NSCLC. The NPV was about 91% in clinical N(0) patients, suggested that (18)F-FDG PET/CT may help to accurately stage N(0) patients and thus identify patients for SBRT.

Negative predictive value of positron emission tomography and computed tomography for stage T1-2N0 non-small-cell lung cancer: a meta-analysis

BACKGROUND

Nodal staging of non-small-cell lung cancer (NSCLC) is crucial in evaluation of prognosis and determination of therapeutic strategy. This study aimed to determine the negative predictive value (NPV) of combined positron emission tomography and computed tomography (PET-CT) in patients with stage I (T1-2N0) NSCLC and to investigate the possible risk factors for occult nodal disease.

METHODS

Studies investigating the performance of PET in conjunction with CT in the nodal staging of stage I NSCLC were identified in the MEDLINE database. The initiative of standards for reporting of diagnostic accuracy (STARD) was used to ensure study quality. Pathologic assessments through mediastinoscopy or thoracotomy were required as the reference standard for evaluation of PET-CT accuracy. Stata-based meta-analysis was applied to calculate the individual and pooled NPVs.

RESULTS

Ten studies with a total of 1122 patients with stage I (T1-2N0) NSCLC were eligible for analysis. The NPVs of combined PET and CT for mediastinal metastases were 0.94 in T1 disease and 0.89 in T2 disease. Including both T1 disease and T2 disease, the NPVs were 0.93 for mediastinal metastases and 0.87 for overall nodal metastases. Adenocarcinoma histology type (risk ratio [RR], 2.72) and high fluorine-18 (18F) fluorodeoxyglucose (FDG) uptake in the primary lesion were associated with greater risk of occult nodal metastases.

CONCLUSIONS

Although overall occult nodal metastases in clinical stage T1-2N0 NSCLC is not infrequent, combined PET and CT provide a favorable NPV for mediastinal metastases in T1N0 NSCLC, suggesting a low yield from routine invasive staging procedures for this subgroup of patients.

Combining transbronchial biopsy using endobronchial ultrasonography with a guide sheath and positron emission tomography for the diagnosis of small peripheral pulmonary lesions

To evaluate the combination of transbronchial biopsy (TBB) using endobronchial ultrasonography with a guide sheath (EBUS-GS) and positron emission tomography with fluorodeoxyglucose (FDG-PET) for the diagnosis of small peripheral pulmonary lesions (PPLs) < or = 30 mm in mean diameter. A total of 74 PPLs (69.2%) were diagnosed by TBB using EBUS-GS with X-ray fluoroscopy. Diagnostic yield by FDG-PET was 78.5% for the 107 PPLs examined. Diagnostic yield with the combination of TBB using EBUS-GS and FDG-PET (90.7%) was significantly higher compared with that for each procedure alone. A significant increment in diagnostic yield with this combination was seen for PPLs >20mm and < or = 30 mm and for malignant lesions. Combination of TBB using EBUS-GS and FDG-PET is useful for the diagnosis of small PPLs.

Multidisciplinary Evaluation of Patients With Suspected Lung Cancer

Lung cancer diagnosis and treatment has evolved to require the input and expertise of multiple diverse medical and surgical specialties. The approach to lung cancer patients requires the adherence to a few principles that include thorough use of staging modalities to assure the proper treatment for each patient, and an understanding of the limitations and advantages of each of these modalities. Evidence is continuing to emerge that supports the notion that diagnostic workup and treatment of lung cancer patients is best done within the context of a multidisciplinary team devoted to this purpose.

18F-FDG PET/CT in mediastinal lymph node staging of non-small-cell lung cancer in a tuberculosis-endemic country: consideration of lymph node calcification and distribution pattern to improve specificity

PURPOSE

The aim of the study was to assess the accuracy of (18)F-fluorodeoxyglucose (FDG) PET/CT in mediastinal lymph node staging of patients with non-small-cell lung cancer (NSCLC) in a region with a high prevalence of granulomatous disease.

METHODS

Between March 2004 and February 2006, all patients with NSCLC underwent FDG PET/CT and contrast-enhanced thoracic CT, and subsequent surgical resection. PET/CT and contrast-enhanced CT images of 182 patients (126 men and 56 women; mean age 60.7 years) with NSCLC were acquired. Mediastinal node staging was determined using the American Joint Committee on Cancer (AJCC) staging system. Surgical and histological findings served as the reference standard.

RESULTS

A total of 182 patients with 778 mediastinal node stations were evaluated. Sensitivity and specificity of contrast-enhanced CT were 36% and 80% on a per-patient basis and 23% and 92% on a per-node station basis. Sensitivity and specificity of PET/CT were 81% and 73% on a per-patient basis and 75% and 85% on a per-node station basis. After lymph nodes with calcification and bilateral hilar distribution were considered benign, sensitivity and specificity of PET/CT were 75% and 89% on a per-patient basis and 66% and 96% on a per-node station basis.

CONCLUSION

This prospective study suggests that FDG PET/CT can more accurately stage mediastinal lymph nodes than CT. Considering lymph node calcification and distribution pattern could improve specificity at the cost of a decrease in sensitivity.

[The usefulness of PET/CT in lung cancer]

Lung cancer is the leading cause of cancer-related death. Accurate staging is essential for the optimal management and treatment of these patients. Positron emission tomography (PET) and, more recently, PET/CT have been introduced into the diagnostic algorithms for oncologic patients because they provide valuable functional information. The hybrid PET/CT technique acquires both anatomic (CT) and metabolic (PET) images in a single session, combining the benefits of each modality and minimizing their limitations. This article reviews the role of PET/CT in lung cancer staging, with emphasis on non-small cell carcinoma, evaluating the advantages and limitations of the technique. Other applications of the technique, such as planning radiotherapy, are also discussed.

Mediastinal lymph nodes in patients with non-small cell lung cancer: preliminary experience with diffusion-weighted MR imaging

OBJECTIVES

The purpose of our study was to describe our preliminary experience of evaluating mediastinal lymph node metastases with diffusion-weighted magnetic resonance (MR) imaging in patients with non-small cell lung cancer.

MATERIALS AND METHODS

Forty-two consecutive patients with non-small cell lung cancer underwent preoperative diffusion-weighted MR imaging using a non-breath-hold short inversion time inversion recovery-echo planar imaging sequence with a high b value of 1000 s/mm2. An experienced thoracic radiologist prospectively evaluated each study for mediastinal lymph node metastases on a per-patient basis. On diffusion-weighted MR imaging, mediastinal lymph node metastasis was defined as a focus of low signal intensity at the site of a visible lymph node on corresponding T2-weighted image. The MR results were correlated with histopathologic findings.

RESULTS

Diffusion-weighted MR imaging demonstrated mediastinal lymph node metastasis in 4 (80%) of 5 patients with pathologically proven metastasis and accurately identified 36 (97%) of 37 patients without mediastinal lymph node metastasis. Thus, 40 (95%) of 42 patients were accurately diagnosed. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of diffusion-weighted MR imaging for mediastinal lymph node metastasis were 80%, 97%, 80%, 97%, and 95%, respectively.

CONCLUSIONS

Our preliminary results show that diffusion-weighted MR imaging has a high negative predictive value for excluding mediastinal lymph node metastases from non-small cell lung cancer and has the potential to be a reliable alternative non-invasive imaging method for the preoperative staging of mediastinal lymph node in patients with non-small cell lung cancer.

[Imaging and PET/CT of lung cancer]

Lung cancer is one of the most frequently occurring cancer in the world. Imaging plays a critical role for screening, diagnosing, staging, and following patients. Although morphologic imaging such as chest X-ray and CT are still useful for these purpose, major limitations occur in the proper evaluation of diagnosing and staging. Metabolic imaging using PET significantly increases the accuracy of staging. This paper will review the role of imaging in patients suspected or diagnosed with lung cancer.

Noninvasive staging of non-small cell lung cancer: ACCP evidenced-based clinical practice guidelines (2nd edition)

BACKGROUND

Correctly staging lung cancer is important because the treatment options and the prognosis differ significantly by stage. Several noninvasive imaging studies including chest CT scanning and positron emission tomography (PET) scanning are available. Understanding the test characteristics of these noninvasive staging studies is critical to decision making.

METHODS

Test characteristics for the noninvasive staging studies were updated from the first iteration of the lung cancer guidelines using systematic searches of the MEDLINE, HealthStar, and Cochrane Library databases up to May 2006, including selected metaanalyses, practice guidelines, and reviews. Study designs and results are summarized in evidence tables.

RESULTS

The pooled sensitivity and specificity of CT scanning for identifying mediastinal lymph node metastasis were 51% (95% confidence interval [CI], 47 to 54%) and 85% (95% CI, 84 to 88%), respectively, confirming that CT scanning has limited ability either to rule in or exclude mediastinal metastasis. For PET scanning, the pooled estimates of sensitivity and specificity for identifying mediastinal metastasis were 74% (95% CI, 69 to 79%) and 85% (95% CI, 82 to 88%), respectively. These findings demonstrate that PET scanning is more accurate than CT scanning. If the clinical evaluation in search of metastatic disease is negative, the likelihood of finding metastasis is low.

CONCLUSIONS

CT scanning of the chest is useful in providing anatomic detail, but the accuracy of chest CT scanning in differentiating benign from malignant lymph nodes in the mediastinum is poor. PET scanning has much better sensitivity and specificity than chest CT scanning for staging lung cancer in the mediastinum, and distant metastatic disease can be detected by PET scanning. With either test, abnormal findings must be confirmed by tissue biopsy to ensure accurate staging.

Stage T1 non-small cell lung cancer: preoperative mediastinal nodal staging with integrated FDG PET/CT--a prospective study

PURPOSE

To prospectively evaluate the sensitivity and specificity of integrated fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) and computed tomography (CT) (PET/CT) for the preoperative diagnosis of mediastinal nodal metastasis in stage T1 non-small cell lung cancer (NSCLC), with surgical and histologic results as reference standards.

MATERIALS AND METHODS

Institutional review board approval and informed consent were obtained. From June 2003 to February 2005, 150 patients (89 men and 61 women; mean age, 59 years) with stage T1 NSCLC at stand-alone CT underwent integrated PET/CT and surgical staging. Two observers (one radiologist and one nuclear medicine physician) evaluated prospectively and in consensus the mediastinal nodes by analyzing both PET (functional) and CT (anatomic) images. Nodal stages were determined by using the American Joint Committee on Cancer staging system and surgical and histologic findings as the reference standard. Statistical evaluation of malignant lymph nodes was performed on per-nodal-station and per-person bases.

RESULTS

A total of 568 mediastinal nodal stations were evaluated. Nodes were positive for malignancy in 34 (23%) of 150 patients and 55 (10%) of 568 nodal stations. For depiction of malignant nodes, the respective sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of integrated PET/CT were 42% (23 of 55), 100% (513 of 513), 100% (23 of 23), 94% (513 of 545), and 94% (536 of 568) on per-nodal-station basis and 47% (16 of 34), 100% (116 of 116), 100% (16 of 16), 87% (116 of 134), and 88% (132 of 150) on a per-patient basis.

CONCLUSION

Integrated FDG PET/CT provides high specificity and positive predictive value of mediastinal nodal staging in stage T1 NSCLC, although the sensitivity is low.

Quantitative analysis and effect of attenuation correction on lymph node staging of non-small cell lung cancer on SPECT and CT

OBJECTIVE

The purpose of our study was to assess quantitative indexes and the effect of attenuation correction on the evaluation of lymph node metastasis in the staging of non-small cell lung cancer (NSCLC) using fused thallium-201 SPECT/CT images.

MATERIALS AND METHODS

We evaluated 156 lymph nodes (66 metastatic, 90 nonmetastatic) from 29 patients with NSCLC. Using our combined SPECT/CT system, all patients underwent 201Tl SPECT and CT examinations immediately (early images) and 3 hr after (delayed images) the injection of 201Tl. SPECT images were reconstructed with and without attenuation correction. For the quantitative evaluation of lymph node metastasis, we calculated the early ratio, the delayed ratio, and the washout ratio for SPECT images and the short-axis diameter for CT images. Receiver operating characteristic (ROC) analysis was performed in each index for the differentiation between metastatic and nonmetastatic lymph nodes. Visual analysis was also performed by two experienced radiologists.

RESULTS

The area under the ROC curve (A(z)) showed that early ratio and delayed ratio were superior to short-axis diameter for the assessment of lymph node metastasis. In addition, early and delayed ratios on attenuation-corrected images were superior to those ratios on images without attenuation correction. However, the A(z) value for washout ratio was smaller than that for short-axis diameter. Early ratio on attenuation-corrected images was the most useful index (A(z) = 0.94). The sensitivity, specificity, and accuracy for early ratio on attenuation-corrected images were 78.8%, 94.4%, and 87.8% for the diagnosis of lymph node metastasis and 84.6%, 100%, and 93.1% for clinical staging (N0-N1 vs N2-N3), respectively. Fused images showed significantly higher diagnostic accuracy than CT images on visual analysis.

CONCLUSION

Quantitative assessment using fused SPECT/CT images is useful for the diagnosis of lymph node metastasis in patients with NSCLC.

PET/CT Imaging of Lung Cancer

Fluoro-deoxyglucose positron emission tomography (PET) imaging has a diagnostic and prognostic value in the initial staging, restaging, and surveillance of non-small-cell lung cancer (NSCLC). When used in conjunction with conventional radiologic imaging, PET imaging has been shown to result in significant changes in clinical management of NSCLC. Specifically, baseline PET imaging can improve initial staging and guide surgical and radiotherapy planning, whereas repeat PET imaging after the initiation of chemoradiotherapy can predict tumor response and help tailor therapy. After the end of definitive treatment, PET has greater diagnostic accuracy than other imaging modalities for the detection of tumor recurrence. The recent development of fused PET/CT imaging has improved the radiologic evaluation of NSCLC patients by combining metabolic and anatomic imaging; however, this has resulted in more complexity in the image interpretation. It is important for the interpreting physician to understand the role PET/CT plays in the staging, assessment of treatment, and follow-up after therapy in the multidisciplinary management of patients with NSCLC.

Staging of non-small cell lung cancer (NSCLC)

Staging of non-small lung cancer (NSCLC) uses the TNM classification and is undertaken to identify those patients who are surgical candidates, either initially or after chemo-radiotherapy, and to differentiate patients who will be treated radically from those requiring palliation and to plan radiotherapy fields. Computed tomography and magnetic resonance imaging (MRI) are used in staging and provide anatomical information but have well known limitations in differentiating reactive from malignant nodes, fibrosis from active disease and in defining the extent of invasion. MRI, with its superior soft tissue contrast provides optimal information on brachial plexus and central nervous system involvement. Functional imaging using [2- ¹⁸F]fluorodeoxyglucose positron emission tomography is increasingly being used to provide unique information and when combined with anatomic imaging will provide better staging information for both local disease and the extent of metastases.

Positron emission tomographic scanning in the diagnosis and staging of non–small cell lung cancer 2 cm in size or less

OBJECTIVE

Several studies have suggested that positron emission tomography is more accurate than computed tomography for the staging of non-small cell lung cancer and can reduce the rate of unnecessary thoracotomy in patients with potentially resectable disease. However, there are few data on the utility of positron emission tomography in the diagnosis of patients with tumors of 2 cm or less in size.

METHODS

Patients with cT1/cT2 tumors of 2 cm or less in size were retrospectively reviewed. All had a computed tomographic scan, as well as a positron emission tomographic scan on a dedicated scanner, with a standard uptake value reported. A standard uptake value of 2.5 g/mL or greater was considered positive. The results of computed tomography and positron emission tomography were correlated with pathologic results after either resection (n = 60) or mediastinoscopy (n = 4).

RESULTS

Sixty-four patients (38 women; mean age, 66 years) had a mean tumor size of 1.4 cm (range, 0.7-2.0 cm). Forty-three patients had adenocarcinoma, 13 had adenocarcinoma-bronchioloalveolar carcinoma, 5 had squamous cell carcinoma, and 3 had other tumor types. Twenty-nine (45%) tumors had negative positron emission tomographic results. Both tumor size (>1 cm vs < or =1 cm) and cell type (adenocarcinoma-bronchioloalveolar carcinoma vs all other cell types) were significant predictors of positron emission tomography uptake in the primary tumor (P = .05 and .01, respectively). Nodal metastases were detected pathologically in 11 (17%) patients (5 N1 and 6 N2). Positron emission tomographic sensitivity and specificity for nodal metastases were only 45% and 89%, respectively. There was no statistically demonstrable survival difference between positron emission tomography-positive and positron emission tomography-negative tumors (3-year survival of 87% vs 100%, respectively).

CONCLUSION

Positron emission tomographic scanning has no demonstrable benefit in the diagnosis, staging, or prognosis of patients with tumors of 2 cm or less in size.

Meta-analysis of positron emission tomographic and computed tomographic imaging in detecting mediastinal lymph node metastases in nonsmall cell lung cancer

A systematic review was undertaken to select studies that compared the accuracy of 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography with computed tomographic imaging in detecting mediastinal lymph node metastases in patients with nonsmall cell lung cancer. Two authors selected relevant articles according to predefined criteria. With a meta-analytic method, summary receiver operating characteristic curves were constructed. The point on the receiver operating characteristic curve with equal sensitivity and specificity for 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography was Q* = 0.90 (95% confidence interval [CI], 0.86 to 0.95). For computed tomography it was 0.70 (95% CI, 0.65 to 0.75). The difference was highly significant (p < 0.0001). We conclude that 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography is more accurate than computed tomography in detecting mediastinal lymph node metastases.

Should mediastinoscopy actually be incorporated into the FDG PET strategy for patients with non-small cell lung carcinoma?

BACKGROUND

Incorporating mediastinoscopy (MS) into the PET-based strategy for non-small cell lung carcinoma (NSCLC) patients might be cost-effective because MS can allow unnecessary thoracotomies to be avoided. The objective of our study was to assess the cost-effectiveness of incorporating MS into a PET strategy for NSCLC patients.

METHODS

To determine life expectancy (LE), quality adjusted life years (QALY), and the incremental cost-effectiveness ratio (ICER), a decision-tree sensitivity analysis was designed for histopathologically confirmed NSCLC patients with M0 disease, based on the three competing strategies of chest CT only vs. PET + CT vs. PET + CT + MS. A simulation of 1000 NSCLC patients was created using baselines of other relevant variables in regard to sensitivity, specificity, mortality, LE, utilities and cost from published data. One-way sensitivity analyses were performed to determine the influences of mediastinal metastasis prevalence on LE, QALY and ICER.

RESULTS

The LE and QALY per patient in the CT only strategy, PET + CT strategy and PET + CT + MS strategy were 4.79 and 4.35, 5.33 and 4.93 and 5.68 and 5.33 years, respectively, with a 20% prevalence of mediastinal metastasis. The ICERs were 906.6 yen x 10(3) (7555 US dollars)/QALY/patient at a 20% mediastinal metastasis prevalence, and 2194 yen x 10(3) (18,282 US dollars)/QALY/patient at a 50% prevalence, but exceeded 5280 yen x 10(3) (44,000 US dollars)/QALY/ patient at 80%.

CONCLUSIONS

Our study quantitatively showed the CT + PET + MS strategy in place of the PET + CT strategy in managing NSCLC patients to be cost-effective. MS should be incorporated into the PET + CT strategy for NSCLC patients except in those highly suspected of having mediastinal disease on chest CT or PET.

A problem in diagnosing N3 disease using FDG-PET in patients with lung cancer —High false positive rate with visual assessment—

OBJECTIVE

To evaluate the accuracy of diagnosing N3 disease using positron emission tomography (PET) with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) in patients with pulmonary disease.

SUBJECTS AND METHODS

Twenty patients diagnosed as FDG-PET N3 were enrolled. On FDG-PET, lymph nodes were considered to be positive when increased uptake as compared with that of the surrounding mediastinum was visually observed, or the mean standardized uptake ratio (SUR) was more than 2, 2.5, or 3. On CT, lymph nodes exceeding 1 cm in the shortest diameter were regarded as positive.

RESULTS

The PET result was true positive (TP) in 2 patients and false positive (FP) in 18 with an overall accuracy (OA) of 10% using visual criteria. Using an SUR of more than 2.5, the result was TP in 2, FP in 3, and true negative (TN) in 15, the false negative (FN) in 0, with an OA of 85%. CT diagnosis was TP in 2, FP in 9, and TN in 9 with an OA of 55%. The accuracy using the SUR criteria of more than 2.5 was superior to that of CT.

CONCLUSION

Of 20 patients with the diagnosis of PET N3, we found frequent over-diagnosis in nodal staging using the visual criteria.

Seeking a home for a PET, part 2: Defining the appropriate place for positron emission tomography imaging in the staging of patients with suspected lung cancer

In patients who have a high likelihood of having lung cancer, there is little role for positron emission tomography (PET) imaging for diagnosis of the primary lesion. The primary impact of PET imaging is in extrathoracic staging, but it should not replace a clinical evaluation by a physician experienced in lung cancer. PET imaging is most useful for confirmation of the presumed extrathoracic stage in patients with intermediate stages of lung cancer. The role of PET imaging is limited in patients with strong clinical signs of metastatic disease, or in patients with a clinical stage I lung cancer and a negative clinical evaluation. With regard to intrathoracic staging, PET imaging has a definite role in communities in which mediastinoscopy is not available, whereas the impact is limited in institutions in which invasive mediastinal staging is available. The data suggest that a positive PET result in the mediastinum should be confirmed by biopsy. A mediastinoscopy is also reasonable in patients with clinical stage III lung cancer who have no mediastinal PET uptake. It is unclear and controversial whether a biopsy is needed in patients with clinical stage II lung cancer who have no PET uptake in the mediastinum.

False-positive and true-negative hilar and mediastinal lymph nodes on FDG-PET--radiological-pathological correlation

OBJECTIVE

To compare histological findings of FDG-PET false-positive and true-negative hilar and mediastinal lymph nodes.

METHODS

Sixty-seven lymphnode areas in 11 patients who were diagnosed to have N3 lymph nodes by FDG-PET and underwent surgery were histologically examined, and the histopathological findings in false-positive and true-negative lymph nodes were compared. Lymph nodes with higher accumulation of FDG than the surrounding mediastinum level were judged as positive. On histological sections, proportions of macrophages and lymphocytes, amount of coal dust deposit, presence of silicotic nodules, long- and short-axes of the largest node, and volume of macrophages and lymphocytes were evaluated. Correlations between the above-mentioned factors and FDG accumulation were evaluated.

RESULTS

FDG uptake was not correlated with the proportion of macrophages and lymphocytes, coal dust amounts, or the presence of silicotic nodules. The long- and short-axes of the largest node in the false-positive areas were significantly longer than those in the true-negative areas (p = 0.01, and 0.001, respectively). Volumes of lymph nodes (mean +/- SD: 150 +/- 190 mm3) and macrophages (78 +/- 71 mm3) in false-positive areas were markedly larger than those in true-negative areas (68 +/- 87 mm3, p = 0.0009 and 34 +/- 54 mm3, p = 0.0001, respectively). The volume of lymphocytes was also larger in false-positive areas but less markedly.

CONCLUSION

Our study suggested that false-positive results of FDG-PET in hilar and mediastinal lymph nodes were closely related to the size of lymph node and the volume of macrophages.

[ 18 F] 3-deoxy-3′-fluorothymidine positron emission tomography: alternative or diagnostic adjunct to 2-[ 18 f]-fluoro-2-deoxy- d -glucose positron emission tomography in the workup of suspicious central focal lesions?

BACKGROUND

2-[(18)F]-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography has been established as a standard diagnostic imaging method in the preoperative workup of suspicious pulmonary focal lesions, showing a sensitivity of more than 90% and a specificity of about 80%. Determination of malignant pulmonary lesions with FDG positron emission tomography depends on the assessment of glucose metabolism. However, false-positive findings can occur in inflammatory processes, such as sarcoidosis or pneumonia. The thymidine analogue 3-deoxy-3[(18)F]-fluorothymidine (FLT) is a new positron emission tomography tracer that more specifically targets proliferative activity of malignant lesions. The objective of this study was to determine whether FLT positron emission tomography, in comparison with FDG positron emission tomography, provides additional information in the preoperative workup of central pulmonary focal lesions.

METHODS

In this prospective study FLT and FDG positron emission tomography examinations were performed as a part of the preoperative workup in 20 patients with histologically confirmed bronchial carcinoma, 7 patients with benign lesions, and 1 patient with an atypical carcinoid. Results were compared with final pathologic findings.

RESULTS

For staging of the primary tumor, FLT positron emission tomography revealed a sensitivity of 86% and a specificity of 100% compared with a sensitivity of 95% and a specificity of 73% for FDG positron emission tomography. For N staging, the sensitivity of FLT positron emission tomography was 57% and the specificity was 100%, and for FDG positron emission tomography, the sensitivity was 86% and the specificity was 100%, respectively.

CONCLUSIONS

Our preliminary findings indicate specific FLT uptake in malignant lesions. The number of false-positive findings in FDG positron emission tomography might be reduced with FLT positron emission tomography. Therefore positron emission tomography imaging with FLT represents a useful supplement to FDG in assessing the malignancy of central pulmonary focal lesions.

Clinical applications of PET in oncology

Positron emission tomography (PET) provides metabolic information that has been documented to be useful in patient care. The properties of positron decay permit accurate imaging of the distribution of positron-emitting radiopharmaceuticals. The wide array of positron-emitting radiopharmaceuticals has been used to characterize multiple physiologic and pathologic states. PET is used for characterizing brain disorders such as Alzheimer disease and epilepsy and cardiac disorders such as coronary artery disease and myocardial viability. The neurologic and cardiac applications of PET are not covered in this review. The major utilization of PET clinically is in oncology and consists of imaging the distribution of fluorine 18 fluorodeoxyglucose (FDG). FDG, an analogue of glucose, accumulates in most tumors in a greater amount than it does in normal tissue. FDG PET is being used in diagnosis and follow-up of several malignancies, and the list of articles supporting its use continues to grow. In this review, the physics and instrumentation aspects of PET are described. Many of the clinical applications in oncology are mature and readily covered by third-party payers. Other applications are being used clinically but have not been as carefully evaluated in the literature, and these applications may not be covered by third-party payers. The developing applications of PET are included in this review.

Advances in radiological staging of non-small cell lung cancer (NSCLC)

Imaging plays a vital role in the management of non-small cell lung cancer including diagnosis, staging and follow-up. CT and magnetic resonance imaging (MRI) are used in staging and provide anatomical information but have well known limitations in differentiating reactive from malignant nodes, and fibrosis from active disease and in defining the extent of invasion. MRI with its superior soft tissue contrast provides optimal information on brachial plexus and central nervous system involvement. Functional imaging using 2-18 fluoro-deoxyglucose positron emission tomography is increasingly being used to provide unique information and when combined with anatomic imaging will provide better staging information for both local disease and the extent of metastases.

Positron emission tomography scanning for the diagnosis and management of lung cancer

The dissemination of positron emission tomography (PET) technology has enabled a functional approach to the evaluation of lung cancer that complements the anatomic assessment provided by chest radiography, computed tomography (CT) scanning, and magnetic resonance imaging. PET has excellent sensitivity and good specificity for the determination of malignancy in the solitary pulmonary nodule, but these data must be weighed against the evidence of instances of false-positive results because of inflammatory lesions and false-negative results in small- or low-metabolism neoplasms. Therefore, PET may not be advisable when these scenarios apply. Furthermore, in a patient with a very high pretest likelihood of lung cancer (eg, a new or enlarging spiculated nodule in a long-time smoker), the value of PET is less certain because a negative result may be discounted. PET has altered the approach to the staging of lung cancer. It adds value to the evaluation of the mediastinum and extrathoracic structures compared to conventional methods by upstaging or downstaging a substantial proportion of patients. If the staging assessment is negative on PET, the use of mediastinoscopy may be obviated in selected cases. Histologic confirmation of positive PET findings should be obtained before excluding patients from curative resection. PET provides incremental information to CT in the evaluation of persistent and recurrent disease, and response measured on PET appears more accurate as a predictor of ultimate survival. The more recent development of PET-CT permits fusion of anatomic and functional information. Early investigations suggest that this strategy provides superior results compared to either technique alone.

The Utility of 99m Tc Depreotide Compared With F-18 Fluorodeoxyglucose Positron Emission Tomography and Surgical Staging in Patients With Suspected Non-small Cell Lung Cancer

STUDY OBJECTIVES

The findings from conventional imaging modalities, such as chest CT, are frequently unreliable in patients with lung cancer. This study was designed to compare the relative diagnostic accuracies and utility of the two most widely used functional imaging examinations, F-18-2-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) and (99m)Tc depreotide scintigraphy, for the diagnosis and staging of lung cancer.

DESIGN

Prospective, experimental investigation.

SETTING

Academic medical center.

PATIENTS

One hundred sixty-six subjects with suspected lung cancer were enrolled in the study.

INTERVENTIONS

Whole-body and single-photon emission CT imaging of the chest was performed after IV administration of (99m)Tc depreotide. Attenuation-corrected FDG PET imaging was performed after IV administration of FDG. Image findings were compared with the biopsy results or clinical follow-up.

MEASUREMENTS AND RESULTS

In 157 subjects with evaluable lung lesions, the sensitivities and specificities for detecting malignant disease (95% confidence intervals) of FDG PET are 96% (90 to 98%) and 71% (54 to 85%), and of (99m)Tc depreotide are 94% (88 to 98%) and 51% (34 to 68%). In the 139 subjects with available complete staging data, FDG PET correctly staged 76 of 139 patients (55%), and (99m)Tc depreotide correctly staged 63 of 139 patients (45%).

CONCLUSIONS

The sensitivity for detection of lung cancer in the primary lesion is equally high for FDG PET and (99m)Tc depreotide. The specificity is superior for FDG PET. The staging accuracy of FDG PET and (99m)Tc depreotide is similar, but when read with the chest CT neither scintigraphic examination is sufficiently accurate to stage patients with non-small cell lung cancer.