Fluorodeoxyglucose-positron emission tomography in the detection and staging of lung cancer

Performance of [18F]FDG PET/CT versus FAPI PET/CT for lung cancer assessment: a systematic review and meta-analysis

PURPOSE

This article aims to compare the diagnostic performance of 18-fluorodeoxyglucose ([18F]FDG) PET/CT and fibroblast activating protein inhibitor (FAPI) PET/CT in the assessment of primary tumors, lymph nodes, and distant metastases in lung cancer patients.

METHODS

A systematic search was conducted on the Cochrane Library, Embase, and PubMed/MEDLINE databases from inception until November 1, 2022. Included studies assessed the use of FAPI PET/CT and [18F]FDG PET/CT in patients with lung cancer. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool was used to evaluate the risk of bias. A random variable model was used to analyze the diagnostic tests of the two imaging modalities.

RESULTS

The sensitivity of FAPI PET/CT in detecting primary lung cancer lesions was 0.98 (95% CI: 0.88-1.00), while the sensitivity of [18F]FDG PET/CT was 0.99 (95% CI: 0.74-1.00). For the detection of metastatic lesions (lymph node metastases and distant metastases), FAPI PET/CT had a sensitivity of 0.99 (95% CI: 0.90-1.00), while the sensitivity of [18F]FDG PET/CT was 0.77 (95% CI: 0.66-0.85). However, the specificity of the two imaging modalities could not be assessed due to the lack of sufficient information on pertinent true negatives.

CONCLUSION

In the diagnosis of metastatic lung cancer lesions, FAPI PET/CT demonstrated a higher sensitivity compared to [18F]FDG PET/CT. Therefore, FAPI PET/CT may be considered an alternative imaging modality for the assessment of primary lung cancer tumors, lymph node metastases, and distant metastases.

CLINICAL RELEVANCE STATEMENT

FAPI may be an alternative to [18F]FDG in the assessment of primary lung cancer tumors, lymph node metastases, and distant metastases, which plays a very important role in treatment.

KEY POINTS

• This article is to compare the performance of [18F]FDG PET/CT with FAPI PET/CT in the assessment of primary tumors, lymph nodes, and distant metastases in lung cancer. • However, FAPI PET/CT has a higher sensitivity for the diagnostic assessment of metastatic lung cancer lesions.

[68Ga]Ga-FAPI PET for the evaluation of digestive system tumors: systematic review and meta-analysis

PURPOSE

Digestive system tumors are a group of tumors with high incidence in the world nowadays. The assessment of digestive system tumor metastasis by conventional imaging seems to be unsatisfactory. [⁶⁸Ga]Ga-FAPI, which has emerged in recent years, seems to be able to evaluate digestive system tumor metastasis. We aimed to summarize the current evidence of [⁶⁸Ga]Ga-FAPI PET/CT or PET/MR for the assessment of primary tumors, lymph node metastases, and distant metastases in digestive system tumors. Besides, we also aimed to perform a meta-analysis of the sensitivity of [⁶⁸Ga]Ga-FAPI PET diagnosis to discriminate between digestive system tumors, primary lesions, and non-primary lesions (lymph node metastases and distant metastases).

MATERIALS AND METHODS

PubMed, MEDLINE and Cochrane Library databases were searched from the beginning of the database build to August 12, 2022. All studies undergoing [⁶⁸Ga]Ga-FAPI PET for the evaluation of digestive tumors were included in the screening and review. Screening and full text review was performed by 3 investigators and data extraction was performed by 2 investigators. Risk of bias was examined with the QUADAS-2 criteria. Diagnostic test meta-analysis was performed with a random-effects model.

RESULTS

A total of 541 studies were retrieved. Finally, 22 studies were selected for the systematic review and 18 studies were included in the meta-analysis. In the 18 publications, a total of 524 patients with digestive system tumors, 459 primary tumor lesions of digestive system tumors, and 1921 metastatic lesions of digestive system tumors were included in the meta-analysis. Based on patients, the sensitivity of [⁶⁸Ga]Ga-FAPI PET for the diagnosis of digestive system tumors was 0.98 (95% CI: 0.94-0.99). Based on lesions, the sensitivity of [⁶⁸Ga]Ga-FAPI PET for the diagnostic evaluation of primary tumor lesions of the digestive system was 0.97 (95% CI: 0.93-0.99); the sensitivity of [⁶⁸Ga]Ga-FAPI PET for the diagnostic evaluation of non-primary lesions (lymph node metastases and distant metastases) of the digestive system tumors was 0.94 (95% CI: 0.79-0.99).

CONCLUSION

[⁶⁸Ga]Ga-FAPI PET has high accuracy and its sensitivity is at a high level for the diagnostic evaluation of digestive system tumors. Clinicians, nuclear medicine physicians, and radiologists may consider using [⁶⁸Ga]Ga-FAPI PET/CT or PET/MR in the evaluation of primary tumors, lymph node metastases, and distant metastases in digestive system tumors.

Liquid biopsy approaches for pleural effusion in lung cancer patients

Genomic profiling of tumors has become the mainstay for diagnosis, treatment monitoring and a guide to precision medicine. However, in clinical practice, the detection of driver mutations in tumors has several procedural limitations owing to progressive disease and tumor heterogeneity. The current era of liquid biopsy promises a better solution. This diagnostic utility of liquid biopsy has been demonstrated by numerous studies for the detection of cell-free DNA (cfDNA) in plasma for disease diagnosis, prognosis, and prediction. However, cfDNAs are limited in blood circulation and still hurdles to achieve promising precision medicine. Malignant pleural effusion (MPE) is usually detected in advanced lung malignancy, which is rich in tumor cells. Extracellular vesicles and cfDNAs are the two major targets currently explored using MPE. Therefore, MPE can be used as a source of biomarkers in liquid biopsy for investigating tumor mutations. This review focuses on the liquid biopsy approaches for pleural effusion which may be explored as an alternative source for liquid biopsy in lung cancer patients to diagnose early disease progression.

A prospective study of the feasibility of FDG-PET/CT imaging to quantify radiation-induced lung inflammation in locally advanced non-small cell lung cancer patients receiving proton or photon radiotherapy

PURPOSE

This prospective study assessed the feasibility of ¹⁸F-2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) to quantify radiation-induced lung inflammation in patients with locally advanced non-small cell lung cancer (NSCLC) who received radiotherapy (RT), and compared the differences in inflammation in the ipsilateral and contralateral lungs following proton and photon RT.

METHODS

Thirty-nine consecutive patients with NSCLC underwent FDG-PET/CT imaging before and after RT on a prospective study. A novel quantitative approach utilized regions of interest placed around the anatomical boundaries of the lung parenchyma and provided lung mean standardized uptake value (SUVmean), global lung glycolysis (GLG), global lung parenchymal glycolysis (GLPG) and total lung volume (LV). To quantify primary tumor metabolic response to RT, an adaptive contrast-oriented thresholding algorithm was applied to measure metabolically active tumor volume (MTV), tumor uncorrected SUVmean, tumor partial volume corrected SUVmean (tumor-PVC-SUVmean), and total lesion glycolysis (TLG). Parameters of FDG-PET/CT scans before and after RT were compared using two-tailed paired t-tests.

RESULTS

All tumor parameters after either proton or photon RT decreased significantly (p < 0.001). Among the 21 patients treated exclusively with proton RT, no significant increase in PVC-SUVmean or PVC-GLPG was observed in ipsilateral lungs after the PVC parameters of primary tumor were subtracted (p = 0.114 and p = 0.453, respectively). Also, there were no significant increases in SUVmean or GLG of contralateral lungs of patients who received proton RT (p = 0.841, p = 0.241, respectively). In contrast, among the nine patients who received photon RT, there was a statistically significant increase in PVC-GLPG of ipsilateral lung (p < 0.001) and in GLG of contralateral (p = 0.036) lung. In the subset of nine patients who received a combined proton and photon RT, there was a statistically significant increase in PVC-GLPG of ipsilateral lung (p < 0.001).

CONCLUSION

Our data suggest less induction of inflammatory response in both the ipsilateral and contralateral lungs of patients treated with proton compared to photon or combined proton-photon RT.

Combining Independent Studies of Diagnostic Fluorodeoxyglucose Positron-Emission Tomography and Computed Tomography in Mediastinal Lymph Node Staging for Non-Small Cell Lung Cancer

Aims and background

A meta-analysis of diagnostic test performance was conducted to compare the results of relevant studies reporting diagnostic accuracy values for mediastinal staging in patients with non-small cell lung cancer (NSCLC). This paper deals with the two most accurate imaging techniques currently in use: positron emission tomography (PET) with FDG and computed tomography (CT). A statistical pooling method was used to perform a quantitative meta-analysis aimed at demonstrating the potential advantage of one of these two methods.

Methods

Studies in all languages published between 1998 and 2005 that examined the use of FDG-PET and CT for mediastinal staging in NSCLC patients, enrolled at least 18 participants, and provided enough data to allow calculation of sensitivity and specificity rates were considered eligible for the quantitative meta-analysis. Statistical methods to pool the overall estimates of sensitivity and specificity and to compare the discriminant power of PET and CT were discussed and used.

Results

Of the 13 studies included in the analysis, 12 reported greater accuracy of FDG-PET than CT in detecting mediastinal lymph node metastases. The sensitivity of FDG-PET ranged from 50% to 100%. The estimate of the overall sensitivity was 0.83% with 95% CI (0.749–0.913). Specificity ranged from 79% to 100%, with an overall estimated specificity of 0.87% with 95% CI (0.80–0.95). For CT, the sensitivity and specificity ranged from 50% to 97% and 58% to 94%, respectively; the overall estimate was 0.68% with 95% CI (0.582–0.788) and 0.76% with 95% CI (0.668–0.859). The summary receiver operating characteristic (SROC) approach was used to assess the superior diagnostic accuracy of one of the two methods. The areas under the two SROC curves were AUCPET = 0.909 vs AUCCT = 0.794.

Conclusions

Numerical and visual results of the meta-analysis of recent relevant reports agreed that FDG-PET is more accurate than CT in identifying mediastinal lymph node metastases in non-small cell lung cancer.

Liquid Biopsies in the Screening of Oncogenic Mutations in NSCLC and its Application in Targeted Therapy

Non-small cell lung cancer (NSCLC) still dominates cancer-related deaths in America. Despite this, new discoveries and advancements in technology are helping with the detection and treatment of NSCLC. The discovery of circulating tumor DNA in blood and other biofluids is essential for the creation of a DNA biomarker. Limitations in technology and sequencing have stunted assay development, but with recent advancements in the next-generation sequencing, droplet digital PCR, and EFIRM, the detection of mutations in biofluids has become possible with reasonable sensitivity and specificity. These methods have been applied to the detection of mutations in NSCLC by measuring the levels of circulating tumor DNA. ALK fusion genes along with mutations in EGFR and KRAS have been shown to correlate to tumor size and metastasis. These methods allow for noninvasive, affordable, and efficient diagnoses of oncogenic mutations that overcome the issues of traditional biopsies. These issues include tumor heterogeneity and early detection of cancers with asymptomatic early stages. Early detection and treatment remain the best way to ensure survival. This review aims to describe these new technologies along with their application in mutation detection in NSCLC in order to proactively utilize targeted anticancer therapy.

CT and PET-CT of a dog with multiple pulmonary adenocarcinoma

A 10-year-old, intact female Yorkshire terrier had multiple pulmonary nodules on thoracic radiography and ultrasonography with no lesions elsewhere. Computed tomography (CT) and positron emission tomography and computed tomography (PET-CT) using 18F-fluorodeoxyglucose (FDG) were performed to identify metastasis and undetected primary tumors. On CT examination, pulmonary nodules had a hypoattenuating center with thin peripheral enhancement, suggesting ischemic or necrotizing lesion. In PET-CT at 47 min after intravenous injection of 11.1 MBq/kg of FDG, the maximum standardized uptake value of each pulmonary nodule was about from 3.8 to 6.4. There were no abnormal lesions except for four pulmonary nodules on the CT and PET-CT. Primary lung tumor was tentatively diagnosed, and palliative therapy using 2 mg/kg tramadol and 2.2 mg/kg carprofen twice per day was applied. After the dog’s euthanasia due to deteriorated clinical signs and poor prognosis, undifferentiated pulmonary adenocarcinoma was diagnosed through histopathologic and immunochemistry examination. To the best of the authors’ knowledge, this is the first study of CT and PET-CT features of canine pulmonary adenocarcinoma. In this case, multiple pulmonary adenocarcinoma could be determined on the basis of FDG PET-CT through screening the obvious distant metastasis and/or lymph node invasions and excluding unknown primary tumors.

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.

The efficacy of PET staging for small-cell lung cancer: a systematic review and cost analysis in the Australian setting

INTRODUCTION

This study aimed to establish from the published literature the efficacy of a positron emission tomography (PET)-based strategy for the staging of small-cell lung cancer compared to conventional methods, the potential impact on patient management and outcomes, and cost implications for the Australian health system.

METHODS

EMBASE, Current Contents, PubMed, and OVID, databases were searched using relevant search terms. Reference lists of identified studies were examined for additional pertinent papers. Literature review identified 22 relevant studies containing data for 1663 patients. Studies were evaluated regarding the adequacy of pathological or clinical correlation of imaging findings. Efficacy of PET-staging was analyzed. The Medicare benefits schedule was used to compare costs of the two strategies.

RESULTS

Published data confirm that PET staging has a sensitivity approaching 100% and specificity exceeding 90%. Data suggest that compared to conventional staging, PET can alter management (including radiotherapy portal changes) in at least 28% of patients, can result in the addition of life-prolonging radiotherapy in 6%, and avert unnecessary radiotherapy with associated toxicity in 9%. PET-based staging costs 1603 Australian dollars (AUD) and conventional staging 1610 AUD per patient. An additional 540,354 AUD may be saved annually through avoidance of unnecessary radiotherapy.

CONCLUSIONS

PET-based staging seems superior to conventional staging, and can significantly alter patient management particularly with regard to the inclusion, omission, and portal design of radiotherapy. The initial costs of the two strategies do not seem significantly different. PET may ultimately reduce healthcare costs through avoidance of inappropriate thoracic radiotherapy. The major advantages of PET-staging may, however, lie in averting unnecessary toxicity and in the appropriate addition of thoracic radiotherapy with potential survival gains.

Preclinical evaluation of [99m]Tc-labeled doxorubicin as a potential scintigraphic probe for tumor imaging

BACKGROUND

The currently available radiopharmaceuticals are not specific for tumor imaging.

PURPOSE

The present study was conducted to radiolabel doxorubicin with Technetium-99m ([99m]Tc) as a scintigraphic marker of high DNA turnover/intercalation in malignant cells.

METHODS

Labeling was done by direct method and the developed radiotracer was subjected to quality control tests. The blood kinetics, scintigraphy of tumor-bearing mice, and biodistribution were studied after intravenous injection of about 7.4 MBq of [99m]Tc-doxorubicin. The isotime (5 minutes) anterior images were acquired at different time intervals of 1.5, 3, and 4 hours.

RESULTS

The labeling efficiency of [99m]Tc-doxorubicin was estimated to be more than 95%. The protein-binding efficiency was greater than 88% and in vitro stability was up to 24 hours. The biodistribution data support the clearance of the radioligand by dual (renal and hepatic) pathways. A semiquantitative data analysis of the anterior images indicated that a focal concentration of the radiotracer was seen in the tumor at 1.5 hours, which persisted in 3-hour and 4-hour images, respectively.

CONCLUSIONS

This scintigraphic approach, therefore, could be a powerful tool for cancer detection at early stage. The technique, however, needs further validation through animal experimentation and clinical studies.

Clinical application of positron emission tomography in designing radiation fields in non-small cell lung cancer patients

There is significant interest in incorporating positron emission tomography (PET) into radiation therapy planning, although limited data exist that separately consider its diagnostic accuracy with respect to the primary tumor, hilum and mediastinum. This study evaluates the accuracy of PET planning by region of interest. Between January 2003 and July 2005, 351 patients with a pre-operative PET study underwent surgical resection. Of this population, 257 (73%) patients with a diagnosis of non-small cell lung cancer were evaluated. PET study findings regarding the suspected primary tumor site, ipsilateral hilum and mediastinum were correlated with surgical pathology for determination of accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). The accuracy of the primary site (95%), ipsilateral hilum (80%) and mediastinum (84%) was relatively high. The NPV of the ipsilateral hilum and mediastinum was also high (92 and 86%, respectively). However, the PPV of the ipsilateral hilum (31%) and mediastinum (75%) was lower. PET accuracy evaluating bronchoalveolar primary tumors was lower vs. other histologies (86 vs. 96%, p=0.02), although there was no difference with regard to the hilum or mediastinum. PET scanning may be an important tool in designing radiation treatment fields for lung cancer when combined with other imaging modalities. However, caution must be exercised when evaluating lymph node regions, as the PPV is not as high for the ipsilateral hilum and mediastinum as for the primary tumor. The NPV is high for nodal regions and may help with the exclusion of large treatment volumes in selected cases.

Evaluation of dual-time-point 18F-FDG PET for staging in patients with lung cancer

(18)F-FDG PET is increasingly used for lung cancer; however, some insufficient results have been reported. The purpose of this study was to evaluate the efficacy of dual-time-point (18)F-FDG PET for staging lung cancer and for differentiating metastatic from nonmetastatic lung cancer lesions.

METHODS

One hundred fifty-five lung cancer patients with known or suspected mediastinal and hilar lymph node involvement or distant metastases underwent whole-body (18)F-FDG PET at 2 time points: scan 1 at 60 min (early imaging) and scan 2 at 180 min (delayed imaging) after (18)F-FDG injection. (18)F-FDG PET findings of nodal and distant metastases were evaluated using conventional imaging, clinical follow-up findings, and the results of autopsy or biopsy.

RESULTS

A total of 580 lesions (155 primary lesions, 315 metastatic lesions, and 110 nonmetastatic lesions) were used for analysis. A closer correlation between the primary lesions and metastases was observed for the retention index (RI) standardized uptake value (SUV) than for early and delayed SUV. There was no relationship between the RI SUV results of primary lesions and those of nonmetastatic lesions. The RI SUV of metastatic lesions was approximately 0.5-2 times the RI SUV of primary tumors. We found that the accuracy of (18)F-FDG PET was improved when RI SUV was used for detecting lymph node and distant metastases, because of the significant improvement in specificity relative to early and delayed SUV.

CONCLUSION

RI SUV raised the accuracy for diagnosis of metastases and was superior to early and delayed imaging in terms of differentiating malignancy from nonmetastatic uptake.

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.

Lung cancer with isolated skip metastasis to an abdominal lymph node

BACKGROUND

Lung cancer is usually diagnosed at an advanced stage with metastases present in 40% of patients. The preferential sites of extrapulmonary spread include lymph nodes, liver, brain, adrenal gland, and bone. Direct lymphatic metastases to abdominal lymph nodes without involvement of lobar, hilar or mediastinal lymph nodes is rare.

CASE REPORT

We report a case of adenocarcinoma of the lung in the left lower lobe, with isolated metastasis to an abdominal lymph node detected by positron emission tomography (PET), followed by confirmation with surgical exploration.

CONCLUSION

The low incidence reported for skip metastasis to the abdominal lymph nodes may be attributed to an underestimation in the past. With the advent of PET computed tomography (PET-CT) and its use as a standard pre-operative staging modality for lung cancer, one should anticipate an increased incidence of skip metastasis.

Clinicopathologic study of resected, peripheral, small-sized, non–small cell lung cancer tumors of 2 cm or less in diameter: Pleural invasion and increase of serum carcinoembryonic antigen level as predictors of nodal involvement

OBJECTIVE

The number of surgical interventions for small-sized lung cancer has increased with the development of computed tomography. We attempted to identify clinicopathologic characteristics of peripheral, small-sized, non-small cell lung cancer to show the limitation of partial resection or segmentectomy.

METHODS

A retrospective analysis of 143 patients who underwent a complete resection for a peripheral non-small cell lung cancer of 2 cm or less in diameter was performed. The relationships between nodal involvement and other clinical factors were also assessed in patients who underwent a lobectomy plus node dissection.

RESULTS

The overall 5-year survival rate was 88.1%. The 5-year survival rate was 100% for patients with a tumor of 1.5 cm or less. Survival for patients with adenocarcinoma histology was significantly better than for those with nonadenocarcinoma histology (P = .03). The 5-year survival rate for patients without lymph node metastases was 91.6%, whereas it was 62.5% for those with nodal involvement (P < .01). Increase of prethoracotomy serum carcinoembryonic antigen level was an independent predictor of a poor prognosis. Lymph node metastasis was significantly increased in those with pleural invasion by the primary lesion and increased serum carcinoembryonic antigen level. Fourteen (16.9%) of 83 patients with a tumor diameter of larger than 1.5 cm had nodal metastasis.

CONCLUSIONS

Nodal involvement should be considered in patients with non-small cell lung cancer of 2 cm or less in diameter who show pleural invasion or an increased carcinoembryonic antigen level. A lobectomy with node dissection is recommended for patients with a tumor larger than 1.5 cm, suspected pleural invasion, or prethoracotomy carcinoembryonic antigen level increase.

Positron emission tomography with CT in the evaluation of non-small cell lung cancer in populations with a high prevalence of tuberculosis

OBJECTIVE AND BACKGROUND

To determine the utility of positron emission tomography with CT (PET-CT) in the evaluation of non-small cell lung cancer (NSCLC) in an Asian context where tuberculosis rates are moderately high.

METHODS

Case records of consecutive patients with NSCLC undergoing PET-CT at the Singapore General Hospital over a 1-year period were retrospectively reviewed. The authors evaluated the sensitivity and specificity of PET-CT at their institution using surgical pathology or the tincture of time as the gold standard.

RESULTS

A total of 54 patients underwent PET-CT during this period. Seven patients were evaluated for solitary pulmonary nodule, for which PET-CT gave a sensitivity of 100% and specificity of 75%. There was one patient with false positive PET-CT due to active tuberculosis. In total, 41 patients underwent PET-CT for staging of NSCLC. There was one false positive (patient was found to have active tuberculous lymphadenitis) and one false negative for NSCLC. This gave a sensitivity of 92.3% and a specificity of 95%. Histology from the adrenal glands was available in two patients with PET-CT that was positive for adrenal metastases. One proved to be benign whereas the other was consistent with metastasis. Two patients had PET-CT positive for liver metastases, which was verified by histology. Two patients with positive PET-CT for lesions in the colon turned out to be benign histologically.

CONCLUSIONS

Positron emission tomography with CT for the evaluation and follow-up of solitary pulmonary nodule and NSCLC can provide additional useful information to conventional radiology for treatment planning and a non-invasive determination of prognosis. However, physicians need to be aware of the limitations of this imaging modality, particularly when tuberculosis has a high prevalence in the population.

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.

Selective mediastinal node irradiation based on FDG-PET scan data in patients with non–small-cell lung cancer: A prospective clinical study

PURPOSE

To evaluate the patterns of recurrence when selective mediastinal node irradiation based on FDG-PET scan data is used in patients with non-small-cell lung cancer (NSCLC).

METHODS AND MATERIALS

A prospective Phase I/II study was undertaken on 44 patients with NSCLC without detectable distant metastases on CT and FDG-PET scan, delivering either 61.2 Gy in 34 fractions over 23 days or 64.8 Gy in 36 fractions over 24 days (1.8 Gy b.i.d. with 8-h interval). Only the primary tumor and the positive mediastinal areas on the pretreatment FDG-PET scan were irradiated. Isolated nodal failure was defined as recurrence in the regional nodes outside of the clinical target volume, in the absence of in-field failure.

RESULTS

The CT and FDG-PET stage distribution was as follows: Stage I: 8 patients (18%) and 13 patients (29%); Stage II: 6 patients (14%) and 10 patients (23%); Stage IIIA: 15 patients (34%) and 7 patients (16%); Stage IIIB: 15 patients (34%) and 14 patients (32%), respectively. After a median follow-up time of 16 months (95% confidence interval [CI], 11-21 months) postradiotherapy, 11 patients (25%) developed a local recurrence. Only 1 patient (crude rate, 2.3%; upper bound of 95% CI, 10.3%), with a Stage II tumor on both CT and PET, developed an isolated nodal failure. The median actuarial overall survival was 21 months (95% CI, 14-28 months), and the median actuarial progression-free survival was 18 months (95% CI, 12-24 months).

CONCLUSIONS

Selective mediastinal node irradiation based on FDG-PET scan data in patients with NSCLC results in low isolated nodal failure rates. In the Phase I component of this trial, radiation dose escalation up to 64.8 Gy in 36 fractions over 24 days is feasible.

State-of-the-art FDG-PET imaging of lung cancer

The D-glucose analog 2-(fluorine-18)-fluoro-2-deoxy-D-glucose (FDG) is the most commonly used radionuclide in positron emission tomography (PET) of lung cancer. FDG-PET is a molecular imaging technique that images the preferential accumulation of FDG in malignant tissues with increased metabolism. Although FDG-PET is sensitive in the detection of lung cancer, FDG is not tumor specific and may accumulate in a variety of nonmalignant conditions. Occasional false-negative results may also occur. Whole body FDG-PET is a useful noninvasive technique to stage known or suspected non-small-cell lung cancer. The results allow more efficient use of invasive methods for histopathological staging. The combined use of CT and PET in dual imaging increases the number of patients with correctly staged non-small-cell lung cancer. CT/PET is also useful in the assessment of recurrent or residual disease. Future imaging agents are being developed which may allow more selective accumulation of radiopharmaceutical in malignant tissues.

Increased therapeutic ratio by 18FDG-PET CT planning in patients with clinical CT stage N2-N3M0 non–small-cell lung cancer: A modeling study

PURPOSE

With this modeling study, we wanted to estimate the potential gain from incorporating fluorodeoxyglucose-positron emission tomography (FDG-PET) scanning in the radiotherapy treatment planning of CT Stage N2-N3M0 non-small-cell lung cancer (NSCLC) patients.

METHODS AND MATERIALS

Twenty-one consecutive patients with clinical CT Stage N2-N3M0 NSCLC were studied. For each patient, two three-dimensional conformal treatment plans were made: one with a CT-based planning target volume (PTV) and one with a PET-CT-based PTV, both to deliver 60 Gy in 30 fractions. From the dose-volume histograms and dose distributions on each plan, the dosimetric factors predicting esophageal and lung toxicity were analyzed and compared. For each patient, the maximal tolerable prescribed radiation dose for the CT PTV vs. PET-CT PTV was calculated according to the constraints for the lung, esophagus, and spinal cord. From these results, the tumor control probability (TCP) was estimated, assuming a clinical dose-response curve with a median toxic dose of 84.5 Gy and a gamma(50) of 2.0. Dose-response curves were modeled, taking into account geographic misses according to the accuracy of CT and PET in our institutions.

RESULTS

The gross tumor volume of the nodes decreased from 13.7 +/- 3.8 cm(3) on the CT scan to 9.9 +/- 4.0 cm(3) on the PET-CT scan (p = 0.011). All dose-volume characteristics for the esophagus and lungs decreased in favor of PET-CT. The esophageal V(45) (the volume of the esophagus receiving 45 Gy) decreased from 45.2% +/- 4.9% to 34.0% +/- 5.8% (p = 0.003), esophageal V(55) (the volume of the esophagus receiving 55 Gy) from 30.6% +/- 3.2% to 21.9% +/- 3.8% (p = 0.004), mean esophageal dose from 29.8 +/- 2.5 Gy to 23.7 +/- 3.1 Gy (p = 0.004), lung V(20) (the volume of the lungs minus the PTV receiving 20 Gy) from 24.9% +/- 2.3% to 22.3% +/- 2.2% (p = 0.012), and mean lung dose from 14.7 +/- 1.3 Gy to 13.6 +/- 1.3 Gy (p = 0.004). For the same toxicity levels of the lung, esophagus, and spinal cord, the dose could be increased from 56.0 +/- 5.4 Gy with CT planning to 71.0 +/- 13.7 Gy with PET planning (p = 0.038). The TCP corresponding to these doses was estimated to be 14.2% +/- 5.6% for CT and 22.8% +/- 7.1% for PET-CT planning (p = 0.026). Adjusting for geographic misses by PET-CT vs. CT planning yielded TCP estimates of 12.5% and 18.3% (p = 0.009) for CT and PET-CT planning, respectively.

CONCLUSION

In this group of clinical CT Stage N2-N3 NSCLC patients, use of FDG-PET scanning information in radiotherapy planning reduced the radiation exposure of the esophagus and lung, and thus allowed significant radiation dose escalation while respecting all relevant normal tissue constraints. This, together with a reduced risk of geographic misses using PET-CT, led to an estimated increase in TCP from 13% to 18%. The results of this modeling study support clinical trials investigating incorporation of FDG-PET information in CT-based radiotherapy planning.

Impact thérapeutique de l’imagerie TEP-FDG en carcinologie bronchopulmonaire

BACKGROUND

Because of the expected high performances of scintigraphic scans with [18F]-fluorodeoxyglucose (FDG) not only in diagnostics and but also in therapeutic impact, especially in thoracic oncology, there are a lot of French nuclear medicine departments which will soon be equipped with a positron emission tomograph (PET).

MATERIAL AND METHODS

The Nuclear Medicine Department of the Hôpital d'Instructions des Armées du Val-de-Grâce, Paris, led a retrospective study among physicians interested in 338 FDG-PET exams performed between may 2000 and march 2002 in order to compare its own results with international literature concerning four indications for lung cancer: pulmonary nodule or mass malignancy diagnostic, lung carcinoma extension evaluation, therapeutic efficiency, recurrence suspicion.

RESULTS

There seems to be no divergence, regarding limitation induced by the not exhaustive analysis of the retrospective study: more than every two FDG-PET exam highly influenced the effective therapy.

CONCLUSION

That is why clinical FDG-PET has to be widely developed to investigate lung cancer.

Endoscopic Ultrasound in Non–Small Cell Lung Cancer and Negative Mediastinum on Computed Tomography

Despite technical advances in staging non-small cell lung cancer (NSCLC), accurate staging remains a challenge. Endoscopic ultrasound is useful in staging NSCLC when lymphadenopathy is present on a computed tomography (CT), but its role in the absence of lymphadenopathy on CT has not been well defined. Therefore, we sought to determine the clinical impact of endoscopic ultrasound (EUS) in staging NSCLC in absence of mediastinal lymphadenopathy on CT. Seventy-six patients with NSCLC with absence of mediastinal lymphadenopathy on CT were enrolled and followed prospectively. EUS-guided fine-needle aspiration was performed on sites that were suspicious for metastases. Surgical pathology after thoracotomy was used as the reference standard for assessing accuracy. Sixty-two (86%) patients underwent surgery, and 10 (13%) did not. EUS precluded surgery in 9 patients (12%) and influenced management in 18 (25%) of all patients in this study. EUS detected malignant mediastinal lymphadenopathy more frequently in patients with lower lobe and hilar cancers combined compared with upper lobe cancers (p = 0.004). EUS played a significant role in identifying patients with unresectable (N3) NSCLC when adenopathy was not present on CT imaging and appears to be more sensitive in detecting lymph node metastases in lower lobe and hilar NSCLC compared with upper lobe NSCLC.

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.

Radionuclide imaging of thoracic malignancies

Over the past decade a variety nuclear medicine imaging studies have become available that are of considerable value to patients who have pulmonary malignancies. By far the greatest impact on the management of patients who have thoracic malignancy has been the availability of 18FDG-PET imaging. In the patient who has newly diagnosed lung carcinoma, 18FDG-PET improves the accuracy of staging the disease by identifying or excluding mediastinal disease and distant metastatic foci. 18FDG-PET is superior to anatomic methods for evaluating the response to therapy and for distinguishing recurrent disease from posttreatment changes. Studies are in progress to evaluate the role of 18FDG-PET imaging in assessing prognosis. In patients who have bronchial carcinoid, somatostatin receptor imaging with 111In-DTPA-pentetreotide (Octreoscan) can help identify patients who are candidates for curative surgery, detect unsuspected metastatic spread, and identify patients who might benefit from certain types of medical therapy. Although it was initially speculated that 18FDG-PET imaging would not be sensitive for tumor detection in patients who have neuroendocrine tumors because of the usual slow metabolism and biology of these tumors, many neuroendocrine tumors are positive on 18FDG-PET imaging. Nevertheless, there has been no direct comparison of 18FDG-PET imaging and somatostatin receptor imaging, nor does a positive or negative 18FDG-PET image exclude neuroendocrine tumor. 18FDG-PET imaging and somatostatin receptor imaging with (99m)Tc-depreotide (Neotect) are safe, cost-effective methods that are valuable in the diagnosis and management of patients who have suspected or known lung cancer. 18FDG-PET and (99m)Tc-depreotide imaging have a high degree of sensitivity, specificity, overall accuracy, and positive and negative predictive values in the evaluation of the solitary pulmonary nodule. These agents provide noninvasive, cost-effective methods for selecting patients for aggressive intervention without contributing to increased morbidity. Both methods have incremental value over CT imaging in selecting patients who have solitary pulmonary nodules for invasive biopsy or for thoracotomy.

Positron emission tomography in the management of non–small cell lung cancer

In the past 10 years, FDG-PET has become an important imaging modality in NSCLC. Its indication in the assessment of lung nodules and staging is based on large prospective experience, further supported by some meta-analyses. This evidence has important consequences for patient management, which recently was proved in a randomized trial that showed a reduction in the number of futile thoracotomies by preoperative PET. The use of FDG-PET could become more widespread when commercial isotope distributors are able to deliver FDG so that an on-site cyclotron is no longer a prerequisite. FDG has a half-life of 110 minutes, so a practical distribution radius of 200 km should be feasible. Current indications for PET in the staging of newly diagnosed NSCLC are mainly the patients who are considered to be candidates for radical treatment. The technique does not have a clinical indication in other patients--for example, when metastatic lymph nodes are detected at clinical examination, when a simple ultrasound study already points to diffuse hepatic metastases, or in cases of poor performance status. PET also has prognostic value; it can be used for the evaluation of response or restaging after radiotherapy or chemotherapy and for early detection of relapse. The combination of CT and PET improves radiotherapy planning and it is to be expected that combined CT-PET-guided planning devices will further refine three-dimensional conformal radiotherapy. Finally, a whole new field of application of PET in molecular biology using new radiopharmaceutics is in development. FDG, with its possibility to study tumor glucose metabolism, has paved the way for PET in clinical oncology. It is hoped that PET examinations with new molecular tracers will allow ever better specificity and become sufficiently reliable and manageable to evaluate receptors, transport proteins, and intracellular enzymes so that very early response monitoring during chemotherapy or radiotherapy, evaluation of novel molecular-targeted lung cancer therapies, or even gene therapy becomes possible. New tracers that have showed their promise in early clinical studies include 18F-fluorothymidine (a proliferation marker that might give better specificity in the assessment of solitary pulmonary nodules or better accuracy in the evaluation of early response), (99m)Tc-Annexin V (Apomate; an apoptosis-imaging agent that could be correlated with overall and progression-free survival in phase I data), or 18F-fluoromisonidazole (which can be used to quantify regional hypoxia in human tumors with PET).

New radiotherapy technologies

Conventional radiation therapy has had limited success in curing inoperable lung cancer due to poor local control. There is evidence to suggest that higher doses of radiation will improve local control. In order to safely deliver higher doses of thoracic radiation, advanced treatment techniques are required. Different biologic indices have been utilized to determine whether dose escalation can be safely accomplished, and the results have been reported from many institutions. Tumor motion control aids in treatment since it allows radiation oncologists to more accurately target tumors and therefore to spare more normal tissue from the radiation field. The imaging information from 18-FDG-PET scans also improves target delineation. Advanced treatment delivery techniques, such as three-dimensional conformal radiation therapy, intensity modulated radiation therapy, and stereotactic radiosurgery are also being used to safely escalate the radiation dose. This article explores the current literature on these issues and other advanced radiation therapy techniques.

Detection of lung cancer with positron coincidence gamma camera using fluorodeoxyglucose in comparison with dedicated PET

OBJECTIVE

Dual-head gamma cameras with sodium iodide (NaI) detectors operated in coincidence mode provide a new approach for imaging with positron-labeled tracers. The purpose of this study was to evaluate the feasibility of FDG imaging with positron coincidence detection gamma camera (PCD) in detecting lung tumor in comparison with FDG imaging with the dedicated positron emission tomography (PET).

METHODS AND MATERIAL

Twenty-six lesions of 13 patients with suspected lung cancer were studied with both FDG PET and FDG PCD on the same day. Pulmonary lesions were analyzed visually and semi-quantitatively using the ratio of target-to-background counts (T/B ratio).

RESULTS AND CONCLUSIONS

FDG PCD and FDG PET could detect visually 21 lesions (80.8%) and 23 lesions (88.0%), respectively. The mean T/B ratio and standard deviation (S.D.) of FDG PCD was 4.6 +/- 3.9, significantly lower than that of FDG PET (11.4 +/- 6.6, P<0.001). When pulmonary lesions were no more than 2.0 cm in diameter, the sensitivity of FDG PCD was 37.5%, significantly inferior to that of FDG PET (62.5%, P<0.001). There was no statistically significant difference of the sensitivity between the FDG PCD and FDG PET in lesions of more than 2.0 cm in diameter. FDG PCD with uniform attenuation correction was clinically available in detecting lung cancer. However, the sensitivity for small lesions less than 2.0 cm was limited. The application of measured attenuation correction and scatter correction may to be needed to improve the detectability of FDG PCD, especially for detecting small lung cancer.

Sputum cytology for the detection of early lung cancer

Sputum cytology is an important step in the early diagnosis of roentgenographically occult lung cancer. It identifies primarily intraepithelial lesions, which are the most common squamous carcinomas not detected by helical CT. Patients at highest risk for lung cancer (eg, heavy smokers with airflow obstruction) should undergo sputum cytology. Patients with premalignant lesions (eg, moderate or severe dysplasia) and of course patients with carcinoma in situ or invasive carcinoma should receive fiberoptic bronchoscopy. The diagnosis and treatment of early-stage lung cancer usually has a favorable outcome. Today we have the knowledge and technology that can change the outcome of lung cancer through early identification, particularly in high-risk patients.

Clinical applications of FDG-PET in oncology

Positron emission tomography together with F-18-deoxyglucose (FDG) has emerged as a valuable clinical tool in the field of oncology. FDG-PET diagnoses, stages and restages most cancers with a high diagnostic accuracy. The effects of chemotherapy on tumour metabolism can be monitored with this whole-body technique. Recent studies have established a high prognostic accuracy of PET for predicting the clinical outcome of cancer patients. The current review addresses the role of FDG-PET for diagnosing, staging and restaging of lung cancer, colorectal cancer, lymphoma, melanoma and breast cancer staging and provides a brief outlook for future applications of clinical PET imaging.

Mediastinal lymph node involvement in potentially resectable lung cancer: comparison of CT, positron emission tomography, and endoscopic ultrasonography with and without fine-needle aspiration

PURPOSE

A prospective comparison of three imaging techniques: thoracic CT, positron emission tomography (PET), and endoscopic ultrasonography (EUS) with fine needle aspiration (FNA), each performed under routine conditions, for the detection of metastatic lymph nodes metastases in patients with lung cancer considered for operative resection.

PATIENTS AND METHODS

Following bronchoscopic evaluation, CT, PET, and EUS were performed to evaluate potential mediastinal involvement in 33 consecutive patients with bronchoscopic biopsy/cytology proven (n = 25) or radiologically suspected (n = 8) lung cancer prior to surgery. Surgical histology was used as "gold standard" to confirm the diagnosis of the primary tumor and the mediastinal status in all patients. Histology proved non-small cell lung cancer in 30 patients, neuroendocrine tumor in 1 patient, and benign disease in 2 patients.

RESULTS

The mean age of the study group was 61.5 years (range, 41 to 80 years; 23 male patients). CT, PET, and EUS detected mediastinal lymph nodes (size, 0.4 to 1.6 cm) in 15, 14, and 27 patients (21 of which were suspected to be malignant on EUS), respectively. With respect to the correct prediction of mediastinal lymph node stage, the sensitivities of CT, PET, and EUS were 57%, 73%, and 94%. Specificities were 74%, 83%, and 71%. Accuracies were 67%, 79%, and 82%. Results of PET could be improved when combined with CT (sensitivity, 81%; specificity, 94%; accuracy, 88%). The specificity of EUS (71%) was improved to 100% by FNA cytology (EUS-guided FNA), which gave a tissue diagnosis including tumor type, without complications.

CONCLUSIONS

No single imaging method alone was conclusive in evaluating potential mediastinal involvement in apparently operable lung cancer and routine clinical conditions. A tissue diagnosis is extremely helpful. Because FNA can be performed at the same time as EUS, this combination emerged as the most useful technique in the evaluation of even very small mediastinal metastases of lung cancer. CT seems necessary additionally to evaluate the pretracheal region as well as the rest of the thorax, and PET may be valuable to detect distant metastases.

The role of PET scanning in the evaluation of lung carcinoma

The purpose of the review is to:

provide information concerning the physiology of lung cancer imaging with fluorodeoxyglucose (FDG) positron emission tomography (PET)

clarify the role of FDG-PET in the diagnosis of solitary pulmonary nodules

summarise the accuracy of PET scanning in the staging of lung cancer both in regard to mediastinal nodal staging and the staging of distant metastases.

Staging of non-small cell lung cancer: imaging of intrathoracic disease

This article reviews the contribution of diagnostic imaging to the intrathoracic staging of non-small cell lung cancer. The principle features of the current staging system are discussed along with the relative roles of the various imaging modalities in the evaluation of the primary tumour and metastatic disease. The emerging role of positron emission tomography with fluorodeoxyglucose (FDG-PET) as a clinically useful, potentially cost effective, complementary imaging technique is also reviewed.

Noninvasive staging of non-small cell lung cancer: a review of the current evidence

STUDY OBJECTIVES

To determine the test performance characteristics of CT scanning, positron emission tomography (PET) scanning, MRI, and endoscopic ultrasound (EUS) for staging the mediastinum, and to evaluate the accuracy of the clinical evaluation (ie, symptoms, physical findings, or routine blood test results) for predicting metastatic disease in patients in whom non-small cell lung cancer or small cell lung cancer is diagnosed.

DESIGN, SETTING, AND PARTICIPANTS

Systematic searches of MEDLINE, HealthStar, and Cochrane Library databases to July 2001, and of print bibliographies. Studies evaluating the staging results of CT scanning, PET scanning, MRI, or EUS, with either tissue histologic confirmation or long-term clinical follow-up, were included. The performance of the clinical evaluation was compared against the results of brain and abdominal CT scans and radionuclide bone scans.

MEASUREMENT AND RESULTS

Pooled sensitivities and specificities for staging the mediastinum were as follows: for CT scanning: sensitivity, 0.57 (95% confidence interval [CI], 0.49 to 0.66); specificity, 0.82 (95% CI, 0.77 to 0.86); for PET scanning: sensitivity, 0.84 (95% CI, 0.78 to 0.89); specificity, 0.89 (95% CI, 0.83 to 0.93); and for EUS: sensitivity, 0.78 (95% CI, 0.61 to 0.89); specificity, 0.71 (95% CI, 0.56 to 0.82). For the evaluation of brain metastases, the summary estimate of the negative predictive value (NPV) of the clinical neurologic evaluation was 0.94 (95% CI, 0.91 to 0.96). For detecting adrenal and/or liver metastases, the summary NPV of the clinical evaluation was 0.95 (95% CI, 0.93 to 0.96), and for detecting bone metastases, it was 0.90 (95% CI, 0.86 to 0.93).

CONCLUSIONS

PET scanning is more accurate than CT scanning or EUS for detecting mediastinal metastases. The NPVs of the clinical evaluations for brain, abdominal, and bone metastases are > or = 90%, suggesting that routinely imaging asymptomatic lung cancer patients may not be necessary. However, more definitive prospective studies that better define the patient population and improved reference standards are necessary to more accurately assess the true NPV of the clinical evaluation.

Value of FDG-PET in the management of non-small cell lung cancer

In the past 5 years, metabolic imaging with positron emission tomography (PET) using 18F-fluoro-2-deoxy-glucose (FDG) has become an important imaging modality in lung cancer patients. FDG-PET consistently proved to be superior to structure-based imaging modalities in both the diagnosis and staging of lung cancer. At this moment the use of FDG-PET in these indications needs further validation in multi-centre large-scale randomised studies, focusing mainly on treatment outcome parameters, survival and cost-efficacy. More recently, interesting findings have also been reported in the response assessment to cytotoxic treatments providing information of greater prognostic significance than can be obtained using conventional approaches. This review focuses on the potential role of FDG-PET in the diagnosis of lung nodules and masses, and in locoregional and extrathoracic staging of non-small cell lung cancer. Emphasis is put on the potential clinical implementation of the numerous data of the last decade.

Positron emission tomography in lung cancer

Carcinoma of the lung is one of the most frequent malignancies and a major cause of mortality. The use of positron emission tomography (PET) has been extensively investigated in patients with carcinoma of the lung and has established clinical utility and cost-effectiveness in characterization of solitary pulmonary nodules and preoperative staging of carcinoma of the lung. Evolving applications in carcinoma of the lung include detection of recurrence, assessment of treatment response, radiotherapy planning, and prognosis. In addition, there is developing interest in combined anatomic/metabolic imaging and new tracer techniques, in particular gene expression imaging. This review aims to present existing data supporting the use of PET in carcinoma of the lung and to explore the evolving indications and future prospects of PET and lung cancer.

Development of novel tumor imaging agents with phage-display combinatorial peptide libraries

RATIONALE AND OBJECTIVES

Current radiologic methods do not provide sufficient information for unambiguous diagnosis and prognosis of cancer. The present investigation sought to address this deficiency by developing a system for designing novel small molecules targeted against tumor-specific molecules for use as radionuclide imaging agents.

MATERIALS AND METHODS

Part of a tumor-specific receptor, purified recombinant epidermal growth factor receptor (EGFR), variant III, extracellular domain (rEGFRvIII-ecd), was used as the target in the selection of EGFRvIII-specific peptide ligands from random peptide bacteriophage (phage) display libraries. After three rounds of screening, phage isolates were tested for binding affinity with an enzyme-linked immunosorbent assay. Positive phage were sequenced, and the peptides were synthesized and tested for binding affinity with a surface plasmon resonance assay.

RESULTS

Affinity screening identified 49 peptide-expressing phage that showed enhanced binding to the variant receptor compared with wild-type EGFR. Free peptides from the two phage isolates exhibiting the most favorable binding were tested for target binding. One of these demonstrated a binding affinity for rEGFRvIII-ecd in the 30-nmol/L range.

CONCLUSION

These data suggest that phage display libraries may be very useful in the design of novel, high-affinity tumor imaging agents.