The size of metastatic foci and lymph nodes yielding false-negative and false-positive lymph node staging with positron emission tomography in patients with lung cancer

Enhancing Patient Selection in Stage IIIA-IIIB NSCLC: Invasive Lymph Node Restaging after Neoadjuvant Therapy

Restaging of mediastinal lymph nodes plays a crucial role in the multimodal treatment of stage IIIA Non-Small-Cell Lung Cancer (NSCLC). This study aimed to assess the impact of restaging using endobronchial ultrasound (EBUS), endoesophageal ultrasound (EUS), and transcervical extended mediastinal lymphadenectomy (TEMLA) after neoadjuvant chemotherapy (CHT) or chemoradiotherapy (CRT) on the 5-year overall survival (OS) of patients with NSCLC diagnosed with clinical stage IIIA-IIIB and metastatic ipsilateral mediastinal nodes (N2) who underwent radical pulmonary resections. Patients diagnosed with stage IIIA-IIIB NSCLC and N2 mediastinal nodes were included in this study. Restaging of mediastinal lymph nodes was performed using EBUS, EUS, and TEMLA. The patients were divided into two groups based on the restaging method: the TEMLA restaging group and the chest CT scan-only group. The primary outcome measure was the 5-year OS rate, and the secondary outcome measures included median OS and survival percentages. Statistical analysis, including the log-rank test, was conducted to assess the differences between the two groups. The TEMLA restaging group demonstrated significantly better overall survival compared to the chest CT scan-only group (log-rank test, p = 0.02). This was evident through a four-fold increase in median OS (59 vs. 14 months) and a higher 5-year OS rate of 55.9% (95% CI: 40.6-71.1) compared to 25.0% (95% CI: 13.7-36.3) in the chest CT scan-only group (p = 0.003). Invasive restaging of mediastinal lymph nodes improves the selection of patients with stage IIIA-IIIB (N2) NSCLC after neoadjuvant therapy. The use of EBUS, EUS, and TEMLA provides valuable information for identifying patients who may benefit from surgery by identifying N2 to N0-1 downstaging. These findings emphasize the importance of incorporating restaging procedures into the treatment decision-making process for NSCLC patients with mediastinal lymph node involvement.

Cutaneous adverse reactions in a lung cancer patient treated with pembrolizumab: A case report

Lung cancer is the main cause of oncological death in the US and worldwide, constituting a significant public health problem. The incidence of lung cancer is on the increase. In the present study, the diagnostic process was carried out and treatment options were considered to determine the therapeutic response of a patient diagnosed with lung cancer. The case of an early stage lung cancer patient who benefited from surgical treatment was presented. The pathology report stated the complete diagnosis to be pleomorphic lung cancer with an adenocarcinoma component, pT2aN0M0, with focal positivity for thyroid transcription factor 1 (TTF1), without epidermal growth factor receptor (EGFR) mutations and ALK recombinations, having an initial clinical stage of IB and programmed death ligand-1 (PD-L1) positivity with a tumor proportion score of over 70%. The patient underwent radiotherapy treatment and was administered osteoclast inhibitors and immunotherapy, with no favorable therapeutic effect and with the presence of secondary cutaneous adverse effects to pembrolizumab. As a main cause of death, lung cancer registers a low general survival rate even in patients with targeted therapies or immunotherapy. By better identifying the patients at risk, one can establish a more efficient personalized treatment; the future objective of scientific studies is the follow-up of adverse effects of new therapies.

Clinical Characteristics and Outcome of Pathologic N0 Non-small Cell Lung Cancer Patients With False Positive Mediastinal Lymph Node Metastasis on FDG PET-CT

BACKGROUND/AIM

Preoperative fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET-CT) is a non-invasive and useful diagnostic tool to evaluate mediastinal lymph node (LN) metastasis in lung cancer. However, there are often false-positive LN cases in FDG PET-CT. This study aimed to explore the clinical characteristics and outcome of pathologic N0 non-small cell lung cancer patients with false-positive mediastinal LN on FDG PET-CT.

PATIENTS AND METHODS

We enrolled 147 patients who underwent preoperative FDG PET-CT scan and mediastinal LN dissection. These patients were re-evaluated for post-operative pathologic nodal metastasis and divided into a false-positive group and a group of others.

RESULTS

Among 40 patients diagnosed with clinical N1-3 on FDG PET-CT, 19 (47.5%) patients were pathologic N0, meaning false-positive LN by PET-CT. Preoperative absolute platelet count and platelet-lymphocyte ratio were significantly higher in patients with pathologic N0. The presence of lymphatic invasion was significantly lower in patients with pathologic N0 than in the group of others. Recurrence-free survival was significantly shorter in patients with false positive LN than in patients with true positive LN or true negative LN at the same pathologic stage.

CONCLUSION

Higher absolute platelet count and PLR, lower proportion of lymphatic invasion and shorter recurrence-free survival were associated with false positive mediastinal LN on preoperative FDG PET-CT.

Machine Learning for the Prediction of Lymph Nodes Micrometastasis in Patients with Non-Small Cell Lung Cancer: A Comparative Analysis of Two Practical Prediction Models for Gross Target Volume Delineation

Purpose

The lymph node gross target volume (GTV) delineation in patients with non-small cell lung cancer (NSCLC) is crucial for prognosis. This study aimed to develop a predictive model that can be used to differentiate between lymph nodes micrometastasis (LNM) and non-lymph nodes micrometastasis (non-LNM).

Patients and Methods

A retrospective study involving 1524 patients diagnosed with NSCLC was collected in the First Hospital of Wuhan between January 1, 2017, and April 1, 2020. Duplicated and useless variables were excluded, and 16 candidate variables were selected for further analysis. The random forest (RF) algorithm and generalized linear (GL) algorithm were used to screen out the variables that greatly affected the LNM prediction, respectively. The area under the curve (AUC) was compared between the RF model and GL model.

Results

The RF model revealed that the variables, including pathology, degree of differentiation, maximum short diameter of lymph node, tumor diameter, pulmonary membrane invasion, clustered lymph nodes, and T stage, were more significant for LNM prediction. Multifactorial logistic regression analysis for the GL model indicated that vascular invasion, tumor diameter, degree of differentiation, pulmonary membrane invasion, and maximum standard uptake value (SUVmax) were positively associated with LNM. The AUC for the RF model and GL model was 0.83 (95% CI: 0.75 to 0.90) and 0.64 (95% CI: 0.60 to 0.70), respectively.

Conclusion

We successfully established an accurate and optimized RF model that could be used to predict LNM in patients with NSCLC. This model can be used to evaluate the risk of an individual patient experiencing LNM and therefore facilitate the choice of treatment.

Integrative nomogram of intratumoral, peritumoral, and lymph node radiomic features for prediction of lymph node metastasis in cT1N0M0 lung adenocarcinomas

Radiomics studies to predict lymph node (LN) metastasis has only focused on either primary tumor or LN alone. However, combining radiomics features from multiple sources may reflect multiple characteristic of the lesion thereby increasing the discriminative performance of the radiomic model. Therefore, the present study intends to evaluate the efficiency of integrative nomogram, created by combining clinical parameters and radiomics features extracted from gross tumor volume (GTV), peritumoral volume (PTV) and LN, for the preoperative prediction of LN metastasis in clinical cT1N0M0 adenocarcinoma. A primary cohort of 163 patients (training cohort, 113; and internal validation cohort, 50) and an external validation cohort of 53 patients with clinical stage cT1N0M0 were retrospectively included. Features were extracted from three regions of interests (ROIs): GTV; PTV (5.0 mm around the tumor) and LN on pre-operative contrast enhanced computed tomography (CT). LASSO logistic regression method was used to build radiomic signatures. Multivariable regression analysis was used to build a nomogram. The performance of the nomogram was assessed with respect to its calibration, discrimination, and clinical usefulness. The discriminative performance of nomogram was validated both internally and externally. The radiomic signatures using the features of GTV, PTV and LN showed a good ability in predicting LN metastasis with an area under the curve (AUC) of 0.74 (95% CI 0.60–0.88), 0.72 (95% CI 0.57–0.87) and 0.64 (95% CI 0.48–0.80) respectively in external validation cohort. The integration of different signature together further increases the discriminatory ability: GTV + PTV (GPTV): AUC 0.75 (95% CI 0.61–0.89) and GPTV + LN: AUC 0.76 (95% CI 0.61–0.91) in external validation cohort. An integrative nomogram of clinical parameters and radiomic features demonstrated further increase in discriminatory ability with AUC of 0.79 (95% CI 0.66–0.93) in external validation cohort. The nomogram showed good calibration. Decision curve analysis demonstrated that the radiomic nomogram was clinically useful. The integration of information from clinical parameters along with CT radiomics information from GTV, PTV and LN was feasible and increases the predictive performance of the nomogram in predicting LN status in cT1N0M0 adenocarcinoma patients suggesting merit of information integration from multiple sources in building prediction model.

Selection of Pathological N0 (pN0) in Clinical IA (cIA) Lung Adenocarcinoma by Imaging Findings of the Main Tumor

OBJECTIVES

We would like to clarify the imaging findings of the main tumor that may omit the requirement for lymph node dissection in clinical IA (cIA) lung adenocarcinoma.

METHODS

A total of 336 patients with cIA lung adenocarcinomas with normal preoperative carcinoembryonic antigen (CEA) who underwent surgical resection were analyzed. We investigated the association between various computed tomography (CT) imaging findings or the maximum standardized uptake value (SUVmax) of fluorodeoxyglucose-position emission tomography (FDG-PET) and lymph node metastasis. The maximum tumor diameter was calculated from the CT images using both the lung window setting (LD) and mediastinal window setting (MD). The diameter of the solid component (CD) was defined as consolidation diameter in lung window setting. The solid component ratio (C/T) was defined as CD/LD.

RESULTS

SUVmax, MD, and C/T were independent factors related to lymph node metastasis, but CD was not (p = 0.38). The conditions required for the positive predictive value (PPV) to reach 100% were 10.6 mm for MD, 12.5 mm for CD, and 0.55 for C/T. SUVmax did not reach 100%.

CONCLUSIONS

In cIA lung adenocarcinoma with CEA in the normal range, we found that it may be possible for lymph node dissection to be omitted by MD, CD, and C/T.

Enlarged Mediastinal Lymph Nodes in Computed Tomography are a Valuable Prognostic Factor in Non-Small Cell Lung Cancer Patients with Pathologically Negative Lymph Nodes

Background

Most non-small cell lung cancer patients with enlarged mediastinal lymph nodes (LN) in preoperative computer tomography (CT) images are diagnosed with N0 in the pathological examination after surgery. However, these patients seem to have worse survival than those without enlarged mediastinal LN in our clinical practice. This study aimed to investigate whether the size of mediastinal LN is correlated with the prognosis in pathological N0 patients, which could help us to predict the prognoses further.

Methods

The retrospective cohort study involved 758 N0 patients with a thin layer CT scan. We have measured the size of mediastinal LN, including long diameter, short diameter, and volume on CT image, and classified patients by X-tile. Next, we explored the risk factors of enlarged LN by univariate and multivariate logistic analysis. Then, we have compared the 5-year cancer-specific survival by Kaplan-Meier and log-rank method. Multivariate Cox analysis was utilized to further survival analysis. Finally, we have constructed the prediction model by nomogram.

Results

A total of 150 N0 patients (19.8%) had mediastinal LN enlargement in our study. After multivariate logistic analysis, we found the LN enlargement was significantly correlated with age (p=0.001), pathology (p < 0.001) and tumor recurrence (p < 0.001). The patients with LN enlargement had a worse 5-year cancer-specific survival (75.3% vs 92.8%, p < 0.001) after Kaplan-Meier analysis. Patients with a larger volume had increased risk of tumor-associated death when compared with the normal group (p < 0.001) by multivariate Cox analyses.

Conclusion

N0 patients with larger mediastinal LN had a worse 5-year cancer-specific survival and a higher risk of recurrence. The volume of LN was the most valuable prognostic factor in N0 patients.

Is Biopsy of Contralateral Hilar N3 Lymph Nodes With Negative PET-CT Scan Findings Necessary When Performing Endobronchial Ultrasound Staging?

BACKGROUND

Systematic endobronchial ultrasound (EBUS)-guided lung cancer staging starts with hilar N3 nodes, proceeding sequentially to mediastinal N3, N2, and N1 nodes, with sampling of all enlarged nodes (size, ≥ 5 mm) by EBUS. However, procedure time is limited by patient comfort when moderate sedation is used. It is unclear if EBUS staging should start with hilar N3 nodes or whether starting with mediastinal N3 nodes suffices. Knowing the probability of hilar N3 nodes with PET-CT scan negative findings harboring occult metastasis can inform this decision.

RESEARCH QUESTION

What proportion of patients with hilar N3 nodes showing negative PET-CT scan findings have malignancy by EBUS?

STUDY DESIGN AND METHODS

This retrospective observational, single-center cohort study included consecutive patients with clinical-radiographic T1-3, N0-3, M0 non-small cell lung cancer undergoing systematic EBUS staging with biopsy of hilar N3 nodes with negative PET-CT scan findings. The primary outcome was the proportion of patients with malignant hilar N3 nodes showing negative PET-CT scan findings. Based on expert opinion, a threshold probability of malignancy of less than 5% was considered sufficient to skip hilar N3 nodes. We used the binomial exact test to compare the observed proportion vs threshold probability of 5%.

RESULTS

Of 1,737 consecutive patients undergoing EBUS staging, 1,567 showed negative PET-CT scan findings of the hilar N3 nodes. These nodes were enlarged by EBUS and were sampled in 739 patients. Malignancy was found in the hilar N3 nodes of 5 of 739 patients (0.68%; 95% CI, 0.22%-1.57%). The proportion was significantly less than the threshold probability (P < .001). Patients with positive PET scan results of the mediastinal N3 nodes were at higher risk of having occult hilar N3 nodal metastasis (P = .003), found in 3 of 46 patients (6.5%; 95% CI, 1.4%-17.9%) with positive PET scan results of the mediastinal N3 nodes.

INTERPRETATION

When using moderate sedation, because time is limited, it is reasonable to start with the mediastinal N3 nodes if the hilar and mediastinal N3 nodes show negative PET scan results. Patients with positive PET scan findings of the mediastinal N3 nodes probably should undergo hilar N3 node sampling.

Evaluation of lobar lymph node metastasis in non-small cell lung carcinoma using modified total lesion glycolysis

Background

Volumetric parameters based on 3-dimensional reconstruction have recently been introduced for cancer staging. We aimed to improve the ability to diagnose hilar lymph node metastasis in patients with non-small cell lung cancer.

Methods

We evaluated 142 patients with non-small cell lung cancer who underwent right upper lobectomy and radical lymph node dissection. Metastatic involvement of right upper lobar lymph nodes was assessed using high-resolution computed tomography (HRCT) and 18F-2-floro-2-deoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT).

Results

On receiver operating characteristic (ROC) curve analysis, the area under the curves (AUC) for short axis, maximum of standardized uptake value (SUV_max), total lesion glycolysis (TLG) and modified TLG (mTLG) were 0.79, 0.77, 0.76, and 0.87, respectively. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of mTLG, using the optimal cut off value (2.45), for diagnosis of lobar lymph node metastasis were 71%, 88%, 44%, and 96%, respectively. Hilar asymmetric uptake (HAU) of FDG was larger in true-positive cases than in false-negative cases (P<0.01). Furthermore, the size of metastatic foci in the lymph node was smaller in false-negative cases (P=0.012).

Conclusions

Modified TLG is a good parameter to diagnose metastatic right upper lobar lymph nodes. Micrometastasis in the lymph node is difficult to predict using the current diagnostic method. However, more careful evaluation is required in patients with symmetric FDG accumulation at hilar region because hilar lymph nodes respond to various causes such as benign pulmonary diseases.

Comparison of GLUT-1, SGLT-1, and SGLT-2 expression in false-negative and true-positive lymph nodes during the 18F-FDG PET/CT mediastinal nodal staging of non-small cell lung cancer

INTRODUCTION

Although positron emission tomography (PET) with 2-deoxy-2-[fluorine-18]fluoro-d-glucose integrated with computed tomography (CT), (¹⁸F-FDG PET/CT), has recently improved the mediastinal nodal staging of non-small cell lung cancer (NSCLC), this method can show false negativity. We immunohistochemically investigated the expression of glucose transporters (GLUT-1, SGLT-1, and SGLT-2) in false negative and true positive mediastinal nodes via ¹⁸F-FDG PET/CT.

METHODS

We investigated patients with clinically-diagnosed N0/pathological N2 diseases and patients with clinically-diagnosed N2/pathological N2 disease. The patients who were included in this study were evaluated using ¹⁸F-FDG PET/CT followed by surgical resection between January 2004 and December 2015. The expression of GLUT-1, SGLT-1, and SGLT-2 in the metastatic mediastinal lymph nodes, and clinicopathological variables such as primary tumor size, lymph node size, histological type, and SUV_max of the primary lesion, were compared between false negative nodes and true positive nodes.

RESULTS

The total number of PET false negative metastatic mediastinal lymph nodes was 22 in the 17 patients who were clinical N0/pathological N2, and the number of PET true positives was 15 in the 11 patients who were clinical N2/pathological N2. GLUT-1 expression was positive in five false negative nodes and 10 true positive nodes. SGLT-2 expression was positive in 12 false negative nodes and one true positive node, whereas both false negative and true positive nodes showed no SGLT-1 staining. Univariate analysis showed that the reduced expression of GLUT-1 (P = 0.015), and overexpression of SGLT-2 (P = 0.004) were the significant causative factors for false negative nodes. Multivariate analysis also showed that the reduced expression of GLUT-1 (P = 0.012) and overexpression of SGLT-2 (P = 0.006) were the significant causative factors for false negative nodes.

CONCLUSION

It suggests that the reduced expression of GLUT-1 and overexpression of SGLT-2 are associated with false-negative lymph node metastases in NSCLC.

[Role of PET/CT in primitive non-small cell bronchopulmonary cancer]

Bronchopulmonary cancer is a real public health problem. Morphological imaging plays a central role in its diagnosis, staging as well as post-therapeutic assessment but it has some limitations. Metabolic imaging is a more recent technique which allows to significantly improve the overall imagery performance. We conducted a retrospective, descriptive and analytical study at the Ibn Sina Hospital and at the Military Hospital of instruction Mohammed V in Rabat over a period of 18 months, between September 2014 and February 2016, in order to evaluate the role of Fluorodeoxyglucose-PET/CT in the staging and restaging of non-small cell bronchopulmonary cancer. Initial staging showed a vast majority of locally advanced and metastatic stages: stage IV (40%), Stage IIIB (36%), Stage IIIA (16%), Stage II (8%). PET-CT allowed to detect new sites which were not initially seen on CT scan in 24 cases: 15 new ganglion sites, 8 new adrenal sites and 6 sites of bone lesions. PET/CT allowed to modify initial tumor stage in 60% of cases: upstaging in 23 patients (46%) and downstaging in 7 patients(14%). The initial stage remained unchanged in 40% of patients. Our study confirms the data from the literature concerning the superiority of PET-CT in comparison with CT scan, but only in the optimization of the non-small cell bronchopulmonary cancer management, in particular in locoregional and distant staging.

A Texture Analysis-Based Prediction Model for Lymph Node Metastasis in Stage IA Lung Adenocarcinoma

BACKGROUND

Some clinical N0 lung adenocarcinomas have been pathologically diagnosed as N1 or N2. To improve the preoperative diagnostic accuracy of lymph node disease, we developed a prediction model for lymph node metastasis in cT1 N0 M0 lung adenocarcinoma based on computed tomography texture analysis and clinical characteristics to estimate the probability of lymph node metastasis.

METHODS

The records of 501 consecutive patients with cT1 N0 M0 lung adenocarcinoma who underwent computed tomography scan and pulmonary resection with systematic lymph nodes dissection or lymph nodes sampling were reviewed. Each nodule was manually segmented, and its computerized texture features were extracted. Multivariate logistic regression with fivefold validation was used to estimate independent predictors and build the prediction model. The prediction model was then externally validated. A nomogram was developed based on logistic regression results.

RESULTS

Among 501 patients, 41 were diagnosed with positive lymph nodes (8.18%). Four independent predictors were identified: the skewness and 90th percentile of computed tomography number, nodule compactness, and carcinoembryonic antigen level. This model showed good calibration (Hosmer-Lemeshow test, p = 0.337), with an area under the curve of 0.883 (95% confidence interval, 0.842 to 0.924; p < 0.001). The area under the curve was 0.808 (95% confidence interval, 0.735 to 0.880) when validated with independent data.

CONCLUSIONS

A model based on computerized textures and carcinoembryonic antigen level can assess the lymph node status of patients with cT1 N0 M0 lung adenocarcinoma preoperatively, which could assist surgeons in making subsequent clinical decisions.

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

Aims and background

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

Methods and study design.

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

Results

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

Conclusions

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

Influence of region-of-interest determination on measurement of signal-to-noise ratio in liver on PET images

OBJECTIVE

On ¹⁸F-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography (PET), signal-to-noise ratio in the liver (SNR_liver) is used as a metric to assess image quality. However, some regions-of-interest (ROIs) are used when measuring the SNR_liver. The purpose of this study is to examine the different ROIs and volumes of interest (VOIs) to obtain a reproducible SNR_liver.

METHODS

This study included 108 patients who underwent ¹⁸F-FDG-PET/CT scans for the purpose of cancer screening. We examined four different ROIs and VOIs; a 3-cm-diameter and a 4-cm-diameter circular ROI and a 3-cm-diameter and a 4-cm-diameter spherical VOI on the right lobe of the patients' livers. The average of SUV (SUV_mean), standard deviation (SD) of SUV (SUV_SD), SNR_liver and SD of the SNR_liver obtained using ROIs and VOIs were then compared.

RESULTS

Although the SUV_mean was not different among the ROIs and VOIs, the SUV_SD was small with a 3-cm-diameter ROI. The largest SUV_SD was obtained with a 4-cm-diameter spherical VOI. The SNR_liver and the SD of the SNR_liver with a 4-cm-diameter spherical VOI were the smallest, while those with a 3-cm-diameter circular ROI were the largest. These results suggest that a small ROI may be placed on a relatively homogeneous region not representing whole liver unintentionally.

CONCLUSION

The SNR_liver varied according to the shape and size of ROIs or VOIs. A 4-cm-diameter spherical VOI is recommended to obtain stable and reproducible SNR_liver.

Clinicopathological Characteristics of Lung Adenocarcinoma with Unexpected Lymph Node Metastasis

PURPOSE

The objective is to demonstrate the clinicopathological characteristics of patients with unexpected node-positive lung adenocarcinoma and to analyze predictive factors of unexpected disease.

METHODS

We reviewed 225 patients with lung adenocarcinoma who underwent curative-intent operation between January 2008 and December 2014. Unexpected node-positive diseases were defined as cases with hilar or mediastinal lymph nodes metastasis in spite of both negative significant enlargement of lymph nodes on preoperative chest computed tomography (CT) and negative fluorodeoxyglucose (FDG) uptake in lymph nodes on preoperative positron emission tomography (PET)/CT. We retrospectively analyzed clinical features of these patients and evaluated associated factors for unexpected diseases.

RESULTS

There were 41 patients (18%) with unexpected node-positive disease, consisting of 16 (39%) unexpected pN1 and 25 (61%) unexpected pN2 diseases. The most common predominant subtype was papillary (22 patients; 54%), and 17 patients (41%) had micropapillary component in the tumors. Younger age (p <0.01), left side (p <0.01), larger tumor size (p <0.01), and having a micropapillary component (p <0.01) were significant associated factors of unexpected diseases in multivariate analysis.

CONCLUSION

Histological findings of the primary tumor are often important because they can provide predictive information for lymph nodes status. Having a micropapillary component was one of the significant predictors of unexpected node-positive diseases.

[Role of functional imaging in the definition of target volumes for lung cancer radiotherapy]

Functional imaging with positron emission tomography (PET) is interesting to optimize lung radiotherapy planning, and probably to deliver a heterogeneous dose or adapt the radiation dose during treatment. Only fluorodeoxyglucose (FDG) PET-computed tomography (CT) is validated for staging lung cancer and planning radiotherapy. The optimal segmentation methods remain to be defined as well as the interest of "dose painting" from pre-treatment PET (metabolism: FDG) or hypoxia (fluoromisonidazole: FMISO) and the interest of replanning based on pertherapeutic PET.

Relationship Between the Size of Metastatic Lymph Nodes and Positron Emission Tomographic/Computer Tomographic Findings in Patients with Esophageal Squamous Cell Carcinoma

BACKGROUND

We measured the sizes of metastatic lymph nodes and the relationships thereof by (18)F-fluorodeoxyglucose positron emission tomography/computer tomography (PET/CT). We identified risk factors for nodal upstaging in patients with esophageal squamous cell carcinoma (ESCC).

METHODS

Eighty-five patients with ESCC who underwent esophagectomy with extensive mediastinal lymphadenectomy were assessed. Two radiologists blinded to pathology data reviewed PET/CT scans, evaluating both primary tumors and lymph node involvement. A pathologist examined all metastatic lymph nodes in terms of maximal diameter (LNmax), the size of the metastatic focus (Fmax), and the metastasis occupation ratio (MOR = Fmax/LNmax).

RESULTS

The maximal tumor length averaged 2.9 ± 0.2 cm and the mean SUVmax of the primary lesion 5.3 ± 0.5. On PET/CT scans, 26 (30.6 %) patients exhibited nodal metastasis and 59 (69.4 %) did not. Pathology grades of pN0, pN1, pN2, and pN3 were assigned to 45 (52.9 %), 24 (28.2 %), 13 (15.3 %), and 3 (3.5 %) patients, respectively. Nodal upstaging was evident in 29 (34.1 %) cases. In 123 metastatic nodes of 4212 nodes dissected, the LNmax was 6.60 ± 0.39 mm, the Fmax 4.47 ± 0.35 mm, and the MOR 0.68 ± 0.03. Of 123 nodes, 85 (69.1 %) were retrieved from PET-negative stations, and the LNmax and Fmax values of these nodes were 5.88 ± 0.42 and 3.75 ± 0.31 mm, respectively. Upon multivariate analysis, tumor length (OR 1.666, p = 0.019) and lymphovascular invasion (OR 41.038, p < 0.001) were risk factors for nodal upstaging.

CONCLUSION

A significant proportion of nodal metastases were too small to detect via PET/CT imaging. Therefore, meticulous lymph node dissection might be helpful in ESCC patients.

Systematic Endobronchial Ultrasound-guided Mediastinal Staging Versus Positron Emission Tomography for Comprehensive Mediastinal Staging in NSCLC Before Radical Radiotherapy of Non-small Cell Lung Cancer: A Pilot Study

Despite known limitations of positron emission tomography (PET) for mediastinal staging of non-small cell lung cancer (NSCLC), radiation treatment fields are generally based on PET-identified disease extent. However, no studies have examined the accuracy of FDG-PET/CT on a per-node basis in patients being considered for curative-intent radiotherapy in NSCLC.In a prospective trial, patients with NSCLC being considered for definitive thoracic radiotherapy (± systemic chemotherapy) underwent minimally invasive systematic mediastinal evaluation with endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) following noninvasive staging with integrated PET-CT.Thirty patients underwent EBUS-TBNA, with TBNA performed from a mean 2.5 lymph node (LN) stations per patient (median 3, range 1-5). Discordant findings between PET-CT and EBUS-TBNA were observed in 10 patients (33%, 95% CI 19%-51%). PET-occult LN metastases were demonstrated by EBUS in 4 patients, whereas a lesser extent of mediastinal involvement, compared with FDG-PET, was demonstrated by EBUS in 6 patients, including 2 patients downstaged from cN3 to pN2. LNs upstaged by EBUS were significantly smaller than nodes downstaged by EBUS, 7.5 mm (range 7-9) versus 12 mm (range 6-21), P = 0.005.A significant proportion of patients considered for definitive radiotherapy (+/-chemotherapy) undergoing systematic mediastinal evaluation with EBUS-TBNA in this study have an extent of mediastinal NSCLC involvement discordant with that indicated by PET-CT. Systematic EBUS-TBNA may aid in defining the extent of mediastinal involvement in NSCLC patients undergoing radiotherapy. Systematic EBUS-TBNA has the potential to contribute significantly to radiotherapy planning and delivery, by either identifying occult nodal metastases, or demonstrating FDG-avid LNs to be disease-free.

Current methods of staging and restaging of the mediastinal nodes in non-small-cell lung cancer

To analyze the current methods of primary staging and repeated staging (restaging) of the mediastinal nodes in non-small-cell lung cancer (NSCLC), all methods currently used for staging of NSCLC are analyzed. These methods include imaging techniques [computer tomography (CT), positron emission tomography (PET) combined with CT (PET/CT)], endoscopic/ultrasound techniques (endobronchial ultrasound/transbronchial needle aspiration) and endoscopic ultrasound/fine needle aspiration and surgical techniques [standard cervical mediastinoscopy, video-assisted mediastinoscopy, extended mediastinoscopy, video-assisted mediastinoscopic lymphadenectomy, transcervical extended mediastinal lymphadenectomy, anterior mediastinotomy (Chamberlain procedure) and video-assisted thoracic surgery]. The diagnostic yield of Chest CT is regarded insufficient for both, primary staging and restaging. The PET/CT became a standard imaging technique preceding curative surgery of radical chemo-radiotherapy. The issue of intraoperative staging is also described. Finally, the author’s proposed algorithm of staging, both for primary staging and restaging after neoadjuvant therapy is presented. Detailed staging of NSCLC enables selection of patients with early stage disease for curative surgical/multimodality treatment and helps to avoid unnecessary surgery in advanced disease.

Advantages of FDG-PET/CT over CT alone in the preoperative assessment of lymph node metastasis in patients with esophageal cancer

PURPOSE

The aim of this study was to determine the benefits of (18)F-fluorodeoxyglucose positron emission tomography (PET)/computed tomography (CT) compared to CT alone in the preoperative assessment of lymph node metastasis in patients with esophageal cancer.

METHODS

One-hundred and seven patients who underwent esophagectomy with lymph node dissection between March 2007 and December 2009 were eligible. Sixty-seven patients were treated with surgery alone (SA group), while 40 patients received preoperative treatment prior to surgery (PT group). The pathological results of 1,403 dissected lymph node stations were compared with the results obtained using each imaging modality.

RESULTS

PET/CT showed a significantly higher specificity and positive predictive value (PPV) than CT alone (97.7 vs. 94.1 % and 64.6 vs. 44.0 %, respectively), when analyzed by the lymph node stations. The PPV of PET/CT for N1 cases was significantly better than that of CT alone (78.9 vs. 53.9 %), particularly in the PT group (91.3 vs. 65.4 %). Among the patients in the SA group, the number of metastatic nodes was significantly higher in PET-N1 cases than in PET-N0 cases (5.78 vs. 1.90).

CONCLUSION

PET/CT is useful for selecting patients with multiple lymph node metastases and also for detecting residual metastatic nodes after PT, and thus is beneficial to decide on the appropriate treatment strategy for patients with esophageal cancer.

Sampling versus systematic full lymphatic dissection in surgical treatment of non-small cell lung cancer

The extent of mediastinal lymph node assessment during surgery for non-small cell cancer remains controversial. Different techniques are used, ranging from simple visual inspection of the unopened mediastinum to an extended bilateral lymph node dissection. Furthermore, different terms are used to define these techniques. Sampling is the removal of one or more lymph nodes under the guidance of pre-operative findings. Systematic (full) nodal dissection is the removal of all mediastinal tissue containing the lymph nodes systematically within anatomical landmarks. A Medline search was conducted to identify articles in the English language that addressed the role of mediastinal lymph node resection in the treatment of non-small cell lung cancer. Opinions as to the reasons for favoring full lymphatic dissection include complete resection, improved nodal staging and better local control due to resection of undetected micrometastasis. Arguments against routine full lymphatic dissection are increased morbidity, increase in operative time, and lack of evidence of improved survival. For complete resection of non-small cell lung cancer, many authors recommend a systematic nodal dissection as the standard approach during surgery, and suggest that this provides both adequate nodal staging and guarantees complete resection. Whether extending the lymph node dissection influences survival or recurrence rate is still not known. There are valid arguments in favor in terms not only of an improved local control but also of an improved long-term survival. However, the impact of lymph node dissection on long-term survival should be further assessed by large-scale multicenter randomized trials.

The diagnostic and prognostic value of ¹⁸F-FDG PET/CT in the initial assessment of high-grade bone and soft tissue sarcoma. A retrospective study of 89 patients

PURPOSE

To evaluate the feasibility of (18)F-FDG PET/CT for initial assessment in high-grade bone sarcomas (BS) and soft tissue sarcomas (STS).

METHODS

During the years 2001-2010, 89 patients (30 BS, 59 STS) referred for further evaluation and surgical treatment of a high-grade BS or STS also had a PET/CT scan performed for staging preoperatively (n = 68) or within 1 month of surgery (n = 21). Metastatic lesions suggested on the PET/CT scan were confirmed or rejected by histological evaluation, by additional imaging or by follow-up. In 68 patients (28 BS, 40 STS) the relationship between the maximal standardized uptake value (SUVmax) of the primary tumour and survival was examined.

RESULTS

The PET/CT scan suggested the presence of 13 metastatic lesions in BS patients (5 lymph node, 8 distant) and 21 metastatic lesions (6 lymph node, 15 distant) in STS patients. The calculated sensitivity (SE) and specificity (SP) were 95 % and 96 % for detection of distant metastases, and the predictive value (PV) of a positive or a negative test was 87 % and 98 %, respectively. SE and SP were 100 % and 90 % for detection of lymph node metastases, and the PV of a positive or a negative test was 27 % and 100 %, respectively. The 5-year survival was 81 % among patients with SUVmax below the median value (≤ 10), but was 33 % among those with SUVmax >10.

CONCLUSION

FDG PET/CT for the initial assessment of patients with high-grade BS or STS was feasible with high SE and SP, but in those with lymph node metastases the PV of a positive test was low. The SUVmax of the primary tumour was a strong prognostic factor for survival.

The use and misuse of positron emission tomography in lung cancer evaluation

This article discusses the potential benefits and limitations of positron emission tomography (PET) for characterizing lung nodules, staging the mediastinum, identifying occult distant metastasis, determining prognosis and treatment response, guiding plans for radiation therapy, restaging during and after treatment, and selecting targets for tissue sampling. The key findings from the medical literature are presented regarding the capabilities and fallibilities of PET in lung cancer evaluation, including characterization of pulmonary nodules and staging in patients with known or suspected non-small-cell lung cancer. The discussion is limited to PET imaging with fluorodeoxyglucose.

Lymph node metastasis diagnosis using positron emission tomography with 2-[18F] fluoro-2-deoxy-D-glucose as a tracer and computed tomography in surgical cases of non-small cell lung cancer

OBJECTIVES

Positron emission tomography with 2-[18F] fluoro-2-deoxy-D-glucose as a tracer and computed tomography (FDG-PET/CT) are utilized for the diagnosis of lymph node (LN) metastasis from lung cancer. In this study, we analyzed the diagnostic ability of FDG-PET for N staging by focusing on the clinical features of false-positive (FP) and false-negative (FN) cases.

METHODS

From March 2006 to February 2010, 112 patients underwent preoperative examinations using FDG-PET/CT followed by radical resection with hilar and mediastinal dissection. We analyzed their clinicopathological characteristics based on preoperative FDG-PET/CT findings and post-operative histopathological diagnosis of resected LNs.

RESULTS

Based on the PET/CT results, 17 patients were misdiagnosed (9 FN and 8 FP). The sensitivity, specificity, accuracy and negative and positive predictive values for N1/N2 were 50.0, 94.5, 84.0, 93.0 and 58.3%, respectively, whereas those for N2 were 57.8, 90.3, 84.8, 90.3 and 61.1%, respectively. FP findings more frequently occurred in cases with elevated white blood cell (WBC) count (P=0.015) and smokers (P=0.04). In the FN group, the maximum standardized uptake value for the primary tumour was lower than that in the true-positive (TP) group (P=0.01). The short-axis sizes of 71 LNs differently diagnosed by PET/CT and histopathology findings were significantly smaller in the FN group than the TP group (P<0.001), whereas there was no difference between TP and FP. As for FN LNs in the TP group, there was no significant difference.

CONCLUSIONS

PET/CT showed a good ability to detect metastatic LNs, especially for N2 diagnosis. However, there were some limitations, especially in cases with elevated peripheral WBC count and/or smoking history.

MicroRNAs and lymph node metastatic disease in lung cancer

Lymphatic and distant metastases are primary factors in determining survival in patients with lung cancer. The identification of novel molecular biomarkers that can predict the presence of micrometastasis in lymph nodes and their incorporation in traditional histologic staging is needed. MicroRNAs are emerging as powerful biomarkers for several neoplastic disorders. This article reports the experimental results that have recently led to the identification of several microRNAs deregulated in lung cancer that are strongly associated with lymph node metastasis and advanced clinical stage. This evidence indicates that microRNAs are a promising tool for the clinical management of lung cancer.

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.

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

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

Intratumoural chemotherapy of lung cancer for diagnosis and treatment of draining lymph node metastasis

Objectives

Reviewed here is the potential effectiveness of cytotoxic drugs delivered by intratumoural injection into endobronchial tumours through a bronchoscope for the treatment of non-small cell lung cancer and the diagnosis of occult or obvious cancer cell metastasis to mediastinal lymph nodes.

Key findings

Intratumoural lymphatic treatment may be achieved by injection of cisplatin or other cytotoxic drugs into the malignant tissue located in the lumen of the airways or in the peribronchial structures using a needle catheter through a flexible bronchoscope. This procedure is termed endobronchial intratumoural chemotherapy and its use before systemic chemotherapy and/or radiotherapy or surgery may provide a prophylactic or therapeutic treatment for eradication of micrometastases or occult metastases that migrate to the regional lymph nodes draining the tumour area.

Conclusions

To better elucidate the mode of action of direct injection of cytotoxic drugs into tumours, we review the physiology of lymphatic drainage and sentinel lymph node function. In this light, the potential efficacy of intratumoural chemotherapy for prophylaxis and locoregional therapy of cancer metastasis via the sentinel and regional lymph nodes is indicated. Randomized multicenter clinical studies are needed to evaluate this new and safe procedure designed to improve the condition of non-small cell lung cancer patients and prolong their survival.

Positron-Emission Tomography for Lung Cancer in a Tuberculosis-Endemic Region

A potential limitation of integrated positron-emission tomography and computed tomography in non-small-cell lung cancer may be false-positive results due to granulomatous disease. This retrospective study examined the accuracy of this imaging modality for mediastinal nodal staging of non-small-cell lung cancer in Hong Kong where tuberculosis remains endemic. There were 249 lymph node stations evaluated in 107 patients, of whom 38 (36%) had active tuberculosis or evidence of previous tuberculosis. Imaging results were compared with histological findings. The sensitivity, specificity, and accuracy of integrated imaging for mediastinal nodal staging were 52%, 86%, and 80%, respectively; the overall positive-predictive value for mediastinal nodal metastasis was 46%, and the overall negative-predictive value was 89%. The positive-predictive value for mediastinal nodal metastasis was 39% in patients with tuberculosis and 50% in controls; the negative-predictive value was high in both groups (92% and 87%). The likelihood ratio for true positives was 6.47 in patients with tuberculosis vs. 10.97 in controls. This suggests that the reliability of positron-emission/computed tomography may be substantially poorer in patients with tuberculosis. Histological confirmation should be considered mandatory in patients with suspected metastasis on integrated imaging.

Integrated Positron-Emission Tomography for Nodal Staging in Lung Cancer

As lymph node metastasis is the most important factor determining the surgical outcome of lung cancer, we evaluated the accuracy and clinical usefulness of functional imaging with integrated positron-emission tomography and computed tomography in nodal staging of non-small-cell lung cancer. Between October 2003 and August 2004, 43 newly diagnosed patients underwent curative surgical resection or mediastinoscopic nodal biopsy after chest computed tomography as well as whole-body functional imaging for clinical staging. Based on histopathologic findings in the lymph nodes, we compared the diagnostic usefulness of computed tomography and functional imaging. Twenty-two patients were N0 stage, 6 were N1, 11 were N2, and 4 were N3. Although functional imaging seemed to be superior for evaluation of N2 nodes, there were no significant differences in the sensitivity, specificity, positive-predictive value, negative-predictive value, or accuracy. The situation was similar for N1 nodes, and there were no significant differences except for the false-negative rate. High false-positive and negative-rates for N2 lymph nodes suggest that functional imaging should not replace mediastinoscopy.

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

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

Positron emission tomography in lung cancer

Recent advances in positron emission tomography (PET) with 2-deoxy-2-fluoro [F-18]-D: -glucose (FDG) has enabled not only the diagnosis and staging of lung cancer but also the prediction of its malignancy grade. However, FDG-PET has been known to have several pitfalls for imaging of lung cancer. For the effective clinical use of FDG-PET in lung cancer, we reviewed the pitfalls of using FDG-PET in the diagnosis of pulmonary nodules, semiquantitative analysis of FDG-uptake, N-staging, prediction of tumor aggressiveness, prognostic significance, and prediction of pathological response after chemoradiotherapy.

Diffusion-weighted magnetic resonance imaging can be used in place of positron emission tomography for N staging of non-small cell lung cancer with fewer false-positive results

OBJECTIVE

One of the deficiencies of positron emission tomography for N staging in lung cancer is a false-positive result caused by concurrent lymphadenitis. Recently, diffusion-weighted magnetic resonance imaging has been reported to be able to image tumors of body organs. The aim of this study is to examine the usefulness of diffusion-weighted magnetic resonance imaging for N staging of non-small cell lung cancer compared with positron emission tomography-computed tomography.

METHODS

Both positron emission tomography-computed tomography and diffusion-weighted magnetic resonance imaging were prospectively used in 88 patients before surgical intervention for non-small cell lung cancer to examine 734 lymph node stations. The diagnostic results of positron emission tomography-computed tomography and diffusion-weighted magnetic resonance imaging were compared. The diameters of the metastatic foci within lymph nodes were measured on hematoxylin and eosin-stained sections to compare the detectable size of metastatic foci between positron emission tomography-computed tomography and diffusion-weighted magnetic resonance imaging.

RESULTS

The accuracy of N staging in the 88 patients was 0.89 with diffusion-weighted magnetic resonance imaging, which was significantly higher than the value of 0.78 obtained with positron emission tomography-computed tomography (P = .012), because of less overstaging in the former. Among the 734 lymph node stations examined pathologically, 36 had metastases, and the other 698 did not. Although there was no significant difference in the diagnosis of the 36 metastatic lymph node stations between the 2 methods, diffusion-weighted magnetic resonance imaging was more accurate for diagnosing the 698 nonmetastatic stations than positron emission tomography-computed tomography because of fewer false-positive results (P = .002). The detectable size of metastatic foci within lymph nodes was 4 mm in both positron emission tomography-computed tomography and diffusion-weighted magnetic resonance imaging.

CONCLUSIONS

Diffusion-weighted magnetic resonance imaging can be used in place of positron emission tomography-computed tomography for N staging of non-small cell lung cancer with fewer false-positive results compared with positron emission tomography-computed tomography.

Does positron emission tomography prevent nontherapeutic pulmonary resections for clinical stage IA lung cancer?

BACKGROUND

The American College of Surgeons Oncology Group (ACOSOG) Z0050 trial demonstrated that positron emission tomography (PET) prevents nontherapeutic thoracotomies in a substantial fraction of patients with known or suspected non-small cell lung cancer (NSCLC). However, the benefit of PET in clinical stage IA patients has been questioned due to the lower prevalence of metastases and poor ability to discriminate benign from malignant lung lesions. This study evaluates whether PET prevents nontherapeutic pulmonary resections in clinical stage IA patients by finding advanced disease or by declaring a nodule as benign.

METHODS

We reanalyzed all patients with clinical stage IA NSCLC from ACOSOG Z0050. The clinical, PET, and pathologic stages were compared for this prospective cohort.

RESULTS

One hundred twenty-two clinical stage IA patients were evaluated and 78.7% (96 of 122; 95% confidence interval [CI], 70.4 to 85.6) were eventually shown to have cancer. PET correctly showed 7.4% (9 of 122; 95% CI, 3.4 to 13.5) of patients to have advanced disease (stages IIIA to IV). However, due to a high false positive rate, the positive predictive value for advanced disease was only 33.3% (9 of 27; 95% CI, 16.5 to 54.0). The negative predictive value of PET to predict benign lesions was only 57% (16 of 28; 95% CI, 37.2 to 75.5). Thus, 43% (12 of 28; 95% CI, 24.5 to 62.8) of patients with a PET negative primary lesion actually had cancer, and all of these had resectable disease (stages IA to IIB).

CONCLUSIONS

In clinical stage IA lung cancer patients, PET prevents nontherapeutic pulmonary resections less than 10% of the time. If a strategy of no surgery and serial computed tomographic scans is chosen for PET negative lesions, over 40% of patients with NSCLC will have surgery delayed. A prospective trial comparing PET versus resection for clinical stage IA lesions would clarify the value of PET for these patients.

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.