Case Report: Rare Pulmonary Sclerosing Pneumocytoma: Large, Multiple, Metastatic, and Fatal

Pulmonary sclerosing pneumocytoma (PSP) is a rare benign or low-grade malignant tumor, but it has the potential to present with multiple lesions, lymph node metastasis, extra-pulmonary metastasis, recurrence and even cause death. Herein, a case of PSP that was huge, presented with multiple lesions and had lymph node as well as extrapulmonary metastases (liver, abdominal cavity, bones) is reported for the first time. This patient was also the first one to die of respiratory and circulatory failure caused by the PSP tumor and its metastases which compressed the mediastinal tissue.

Utility of PET/CT in the diagnosis and staging of lung cancer after ecobronchoscopy in mining population

INTRODUCTION

Positron emission tomography (PET) with computerized axial tomography (CT) in a single device is known as PET/CT. It has been widely documented and validated, and it is currently a core part of the diagnosis and staging of lung cancer. However, its reliability has not been analysed in specific populations. The objective of this study is to determine the usefulness of PET/CT in patients exposed to mining activities in which an endobronchial ultrasound (EBUS) has been performed for the diagnosis and/or staging of lung cancer.

PATIENTS AND METHODS

With a prospective and real-time database, all the patients who had undergone an EBUS with suspicion of lung cancer and who had previously undergone a PET/CT were selected. The observation unit was the lymph node and, based on their history of exposure to mining activities, the sample was divided into two categories, group 1: not exposed; and group 2: exposed. In each group, and with the results from anatomical pathology as a dependent variable, logistic models were established to look for independent risk factors for malignancy.

RESULTS

In group 1, lymph nodes larger than 1 cm and PET/CT uptake with maximum standardized uptake value (SUVmax) over 2.5 were independent risk factors for malignancy. However, in group 2 (exposed patients), none of those factors were predictors for malignancy.

DISCUSSION

In the population of individuals with occupational exposure to mining, PET/CT is an imaging technique with diagnostic limitations for lung cancer.

Comparison of 18F-FDG PET/CT and DWI for detection of mediastinal nodal metastasis in non-small cell lung cancer: A meta-analysis

BACKGROUND

Accurate clinical staging of mediastinal lymph nodes of patients with lung cancer is important in determining therapeutic options and prognoses. We aimed to compare the diagnostic performance of diffusion-weighted magnetic resonance imaging (DWI) and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in detecting mediastinal nodal metastasis of lung cancer.

METHODS

Relevant studies were systematically searched in the MEDLINE, EMBASE, PUBMED, and Cochrane Library databases. Based on extracted data, the pooled sensitivity, specificity, positive and negative likelihood ratios (PLR and NLR) with individual 95% confidence intervals were calculated. In addition, the publication bias was assessed by Deek's funnel plot of the asymmetry test. The potential heterogeneity was explored by threshold effect analysis and subgroup analyses.

RESULTS

Forty-three studies were finally included. For PET/CT, the pooled sensitivity and specificity were 0.65 (0.63-0.67) and 0.93 (0.93-0.94), respectively. The corresponding values of DWI were 0.72 (0.68-0.76) and 0.97 (0.96-0.98), respectively. The overall PLR and NLR of DWI were 13.15 (5.98-28.89) and 0.32 (0.27-0.39), respectively. For PET/CT, the corresponding values were 8.46 (6.54-10.96) and 0.38 (0.33-0.45), respectively. The Deek's test revealed no significant publication bias. Study design and patient enrollment were potential causes for the heterogeneity of DWI studies and the threshold was a potential source for PET/CT studies.

CONCLUSION

Both modalities are beneficial in detecting lymph nodes metastases in lung cancer without significant differences between them. DWI might be an alternative modality for evaluating nodal status of NSCLC.

Texture Analysis and Synthesis of Malignant and Benign Mediastinal Lymph Nodes in Patients with Lung Cancer on Computed Tomography

Texture analysis of computed tomography (CT) imaging has been found useful to distinguish subtle differences, which are in- visible to human eyes, between malignant and benign tissues in cancer patients. This study implemented two complementary methods of texture analysis, known as the gray-level co-occurrence matrix (GLCM) and the experimental semivariogram (SV) with an aim to improve the predictive value of evaluating mediastinal lymph nodes in lung cancer. The GLCM was explored with the use of a rich set of its derived features, whereas the SV feature was extracted on real and synthesized CT samples of benign and malignant lymph nodes. A distinct advantage of the computer methodology presented herein is the alleviation of the need for an automated precise segmentation of the lymph nodes. Using the logistic regression model, a sensitivity of 75%, specificity of 90%, and area under curve of 0.89 were obtained in the test population. A tenfold cross-validation of 70% accuracy of classifying between benign and malignant lymph nodes was obtained using the support vector machines as a pattern classifier. These results are higher than those recently reported in literature with similar studies.

F-18-FDG-avid lymph node metastasis along preferential lymphatic drainage pathways from the tumor-bearing lung lobe on F-18-FDG PET/CT in patients with non-small-cell lung cancer

OBJECTIVE

F-18-FDG-avid lymph node (LN) metastasis may preferentially occur along the lymphatic drainage pathway (LDP) from the tumor-bearing lobe in patients with non-small cell lung cancer (NSCLC) on FDG PET/CT. This study evaluated whether the identification of metastatic LNs according to LDP-based visual image interpretation can improve LN staging on FDG PET/CT in these patients.

METHODS

FDG PET/CT study was performed in 265 patients with NSCLC. The presence and LN station of metastatic LNs were determined by surgery or the clinical course. In the LDP-based interpretation, FDG-avid LNs, which were located along the preferential LDP from each tumor-bearing lobe and visually more intense in FDG uptake compared with the remaining LNs straying away from the preferential LDP, were diagnosed as metastatic. The result was compared with the quantitative method using a cutoff value of 2.5 for the maximum standardized uptake value.

RESULTS

Of the total 1031 mediastinal and hilar LN stations with FDG-avid LNs in 265 patients, 179 stations in 66 patients were metastatic and the remaining 852 were benign. All the metastatic LN stations except for 2 stations showing skip metastasis were located along the main preferential LDP or another preferential LDP via a direct anatomic pathway from each tumor-bearing lung lobe. The specificity, accuracy, and PPV for identifying metastatic LN stations by LDP-based interpretation were 97.9, 95.7 and 89.5 %, respectively, which were significantly greater compared with those of 92.7, 90.8 and 70.3 % by the SUV-based method (P < 0.001).

CONCLUSIONS

The present study shows that FDG-avid LN metastasis preferentially occurs along the LDP from the tumor-bearing lobe in NSCLC patients. LDP-based visual image interpretation on FDG PET/CT can improve LN staging in these patients.

Evaluation of the factors affecting the maximum standardized uptake value of metastatic lymph nodes in different histological types of non-small cell lung cancer on PET-CT

Background

To evaluate the factors affecting the maximum standardized uptake value (SUVmax) of metastatic lymph nodes in different histological types of non-small cell lung cancer (NSCLC) on integrated positron emission tomography and computed tomography (PET-CT).

Methods

This was a retrospective, single-institution review of 122 patients with pathologically proven NSCLC who had PET-CT scanning at the same center. Lymph node metastases were pathologically confirmed in tissue specimens from surgical patients. Statistical evaluation of PET-CT results was performed on a per-nodal-station basis.

Results

The tumor SUVmax of squamous cell carcinoma (SCC) (11.0 ± 4.1) was higher than that of adenocarcinoma (AC) (7.4 ± 4.4) (P < 0.01), however, the SUVmax of the metastatic lymph nodes did not differ between the SCC (4.6 ± 3.1) and AC groups(3.6 ± 2.5) (P = 0.221). The SUVmax of metastatic lymph nodes was positively correlated with lymph node size but not with the primary tumor SUVmax, primary tumor size, tumor location and tumor differentiation. The frequency of a SUVmax of lymph nodes ≥2.5 was 44%, 80%,100% in SCC group and 39%, 59%, 90% in AC group when the short-axis diameter of metastatic lymph node was <10 mm, 10–15 mm, and > 15 mm, respectively. The low sensitivity for metastatic lymph nodes on PET-CT was increased when the SUVmax cut-off for malignancy was considered to be above the normal background compared with that when the SUVmax cut-off was above 2.5.

Conclusions

There was no difference in the SUVmax of metastatic lymph nodes in the SCC and AC groups. The SUVmax of metastatic lymph nodes was positively correlated with metastatic lymph node size. There was a high false negative rate if lymph nodes with a short-axis diameter less than 10 mm and a extremely low false negative rate if lymph nodes with a short-axis diameter higher than 15 mm. Although an increased sensitivity may be achieved by decreasing the SUVmax cut-off, invasive staging may still be required for negative lymph nodes due to the lower sensitivity of PET-CT in both SCC and AC.

PET-CT for assessing mediastinal lymph node involvement in patients with suspected resectable non-small cell lung cancer

BACKGROUND

A major determinant of treatment offered to patients with non-small cell lung cancer (NSCLC) is their intrathoracic (mediastinal) nodal status. If the disease has not spread to the ipsilateral mediastinal nodes, subcarinal (N2) nodes, or both, and the patient is otherwise considered fit for surgery, resection is often the treatment of choice. Planning the optimal treatment is therefore critically dependent on accurate staging of the disease. PET-CT (positron emission tomography-computed tomography) is a non-invasive staging method of the mediastinum, which is increasingly available and used by lung cancer multidisciplinary teams. Although the non-invasive nature of PET-CT constitutes one of its major advantages, PET-CT may be suboptimal in detecting malignancy in normal-sized lymph nodes and in ruling out malignancy in patients with coexisting inflammatory or infectious diseases.

OBJECTIVES

To determine the diagnostic accuracy of integrated PET-CT for mediastinal staging of patients with suspected or confirmed NSCLC that is potentially suitable for treatment with curative intent.

SEARCH METHODS

We searched the following databases up to 30 April 2013: The Cochrane Library, MEDLINE via OvidSP (from 1946), Embase via OvidSP (from 1974), PreMEDLINE via OvidSP, OpenGrey, ProQuest Dissertations & Theses, and the trials register www.clinicaltrials.gov. There were no language or publication status restrictions on the search. We also contacted researchers in the field, checked reference lists, and conducted citation searches (with an end-date of 9 July 2013) of relevant studies.

SELECTION CRITERIA

Prospective or retrospective cross-sectional studies that assessed the diagnostic accuracy of integrated PET-CT for diagnosing N2 disease in patients with suspected resectable NSCLC. The studies must have used pathology as the reference standard and reported participants as the unit of analysis.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data pertaining to the study characteristics and the number of true and false positives and true and false negatives for the index test, and they independently assessed the quality of the included studies using QUADAS-2. We calculated sensitivity and specificity with 95% confidence intervals (CI) for each study and performed two main analyses based on the criteria for test positivity employed: Activity > background or SUVmax ≥ 2.5 (SUVmax = maximum standardised uptake value), where we fitted a summary receiver operating characteristic (ROC) curve using a hierarchical summary ROC (HSROC) model for each subset of studies. We identified the average operating point on the SROC curve and computed the average sensitivities and specificities. We checked for heterogeneity and examined the robustness of the meta-analyses through sensitivity analyses.

MAIN RESULTS

We included 45 studies, and based on the criteria for PET-CT positivity, we categorised the included studies into three groups: Activity > background (18 studies, N = 2823, prevalence of N2 and N3 nodes = 679/2328), SUVmax ≥ 2.5 (12 studies, N = 1656, prevalence of N2 and N3 nodes = 465/1656), and Other/mixed (15 studies, N = 1616, prevalence of N2 to N3 nodes = 400/1616). None of the studies reported (any) adverse events. Under-reporting generally hampered the quality assessment of the studies, and in 30/45 studies, the applicability of the study populations was of high or unclear concern.The summary sensitivity and specificity estimates for the 'Activity > background PET-CT positivity criterion were 77.4% (95% CI 65.3 to 86.1) and 90.1% (95% CI 85.3 to 93.5), respectively, but the accuracy estimates of these studies in ROC space showed a wide prediction region. This indicated high between-study heterogeneity and a relatively large 95% confidence region around the summary value of sensitivity and specificity, denoting a lack of precision. Sensitivity analyses suggested that the overall estimate of sensitivity was especially susceptible to selection bias; reference standard bias; clear definition of test positivity; and to a lesser extent, index test bias and commercial funding bias, with lower combined estimates of sensitivity observed for all the low 'Risk of bias' studies compared with the full analysis.The summary sensitivity and specificity estimates for the SUVmax ≥ 2.5 PET-CT positivity criterion were 81.3% (95% CI 70.2 to 88.9) and 79.4% (95% CI 70 to 86.5), respectively.In this group, the accuracy estimates of these studies in ROC space also showed a very wide prediction region. This indicated very high between-study heterogeneity, and there was a relatively large 95% confidence region around the summary value of sensitivity and specificity, denoting a clear lack of precision. Sensitivity analyses suggested that both overall accuracy estimates were marginally sensitive to flow and timing bias and commercial funding bias, which both lead to slightly lower estimates of sensitivity and specificity.Heterogeneity analyses showed that the accuracy estimates were significantly influenced by country of study origin, percentage of participants with adenocarcinoma, (¹⁸F)-2-fluoro-deoxy-D-glucose (FDG) dose, type of PET-CT scanner, and study size, but not by study design, consecutive recruitment, attenuation correction, year of publication, or tuberculosis incidence rate per 100,000 population.

AUTHORS' CONCLUSIONS

This review has shown that accuracy of PET-CT is insufficient to allow management based on PET-CT alone. The findings therefore support National Institute for Health and Care (formally 'clinical') Excellence (NICE) guidance on this topic, where PET-CT is used to guide clinicians in the next step: either a biopsy or where negative and nodes are small, directly to surgery. The apparent difference between the two main makes of PET-CT scanner is important and may influence the treatment decision in some circumstances. The differences in PET-CT accuracy estimates between scanner makes, NSCLC subtypes, FDG dose, and country of study origin, along with the general variability of results, suggest that all large centres should actively monitor their accuracy. This is so that they can make reliable decisions based on their own results and identify the populations in which PET-CT is of most use or potentially little value.

DW MRI at 3.0 T versus FDG PET/CT for detection of malignant pulmonary tumors

Emerging evidence suggests that diffusion-weighted magnetic resonance imaging (DW MRI) could be useful for tumor detection with N and M staging of lung cancer in place of fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT). DW MRI at 3.0 T and FDG PET/CT were performed before therapy in 113 patients with pulmonary nodules. Mean apparent diffusion coefficient (ADC), maximal standardized uptake value (SUVmax ) and Ki-67 scores were assessed. Quantitatively, specificity and accuracy of ADC (91.7 and 92.9%, respectively) were significantly higher than those of SUVmax (66.7 and 77.9% respectively, p < 0.05), although sensitivity was not significantly different between them (93.5 and 83.1%, p > 0.05). Qualitatively, sensitivity, specificity and accuracy of DW MRI (96.1, 83.3 and 92.0%, respectively) were also not significantly different from that of FDG PET/CT (88.3, 83.3 and 86.7%, respectively, p > 0.05). Significant negative correlation was found between Ki-67 score and ADC (r = -0.66, p < 0.05), ADC and SUVmax (r = -0.37, p < 0.05), but not between Ki-67 score and SUVmax (r = -0.11, p > 0.05). In conclusion, quantitative and qualitative assessments for detection of malignant pulmonary tumors with DW MRI at 3.0 T are superior to those with FDG PET/CT. Furthermore, ADC could predict the malignancy of lung cancer.

The maximum standardized uptake value of fluorodeoxyglucose positron emission tomography of the primary tumour is a good predictor of pathological nodal involvement in clinical N0 non-small-cell lung cancer

OBJECTIVES

Fluorodeoxyglucose positron emission tomography (FDG-PET) plays an important role in the evaluation of resectable non-small-cell lung cancer (NSCLC). However, this modality cannot be used to detect histological nodal involvement, which can result in stage-migration for resectable lung cancer. In this study, we tried to evaluate the possibility of predicting histological nodal involvement in patients with NSCLC using the maximum standardized uptake value (SUVmax) of FDG-PET of the primary tumour instead of that of the lymph nodes.

METHODS

Between February 2008 and September 2011, 898 patients underwent lung cancer surgery at our institute. Among them, we retrospectively analysed 265 patients with clinical N0 NSCLC, who underwent preoperative FDG-PET. The relationships between clinicopathological features, including the findings of FDG-PET and pathological nodal involvement, were investigated. The factors investigated were age, gender, preoperative carcinoembryonic antigen titre, maximum tumour dimension, consolidation/tumour dimension ratio (C/T ratio), SUVmax in the primary tumour and smoking history.

RESULTS

Of the 265 clinical N0 NSCLC patients, 214 (80.8%) had pathological N0 status and 27 (10.2%) and 24 (9.0%) had pathological N1 and N2 disease. In a multivariate analysis, the C/T ratio (P = 0.046) and SUVmax of the primary tumour (P = 0.016) were significant predictors of pathological nodal involvement. With regard to pathological N1-2 disease, the sensitivity, specificity, accuracy and positive and negative predictive values of mediastinal node involvement in patients with NSCLC with an SUVmax for FDG-PET of 10 or more were 49.0, 83.2, 76.6, 41.0 and 87.3%, respectively. Of the 61 patients with NSCLC with an SUVmax for FDG-PET of 10 or more, 25 (41.0%) had pathological N1-2 disease, while only 26 (12.7%) of the remaining 204 patients with an SUVmax for FDG-PET of <10 had nodal disease (P < 0.0001).

CONCLUSIONS

Postoperative nodal status was significantly predicted by the SUVmax of FDG-PET of the primary tumour instead of the lymph nodes themselves. The patients with NSCLC in particular who show strong uptake values of SUVmax in the primary tumour could have occult nodal metastases, and may be indicated for a further preoperative modality for an accurate staging.

Diagnostic value of fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography for the detection of metastases in non-small-cell lung cancer patients

In the recent years, fluorine 18 fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET)/computed tomography (CT) has emerged as a new modality for staging non-small-cell lung cancer (NSCLC) patients. The aim of this meta-analysis was to assess the diagnostic value of (18)F-FDG PET/CT in detecting metastatic lesions in NSCLC patients. Meta-analysis methods were used to pool sensitivity, specificity, positive and negative likehood ratios, diagnostic odd ratios and to construct a summary receiver-operating characteristic curve. Data from included studies were pooled to compare the diagnostic accuracy between PET/CT and PET or CT alone in nodal staging. Totally, 56 studies involving 8,699 patients met the inclusion criteria. The pooled sensitivities and specificities of (18)F-FDG PET/CT were 0.72 [95% confidence interval (CI): 0.65-0.78] and 0.91 (95% CI: 0.86-0.94) in determining mediastinal nodal staging; 0.71 (95% CI: 0.60-0.80) and 0.83 (95% CI: 0.77-0.88) in intrathoracic staging; 0.78 (95% CI: 0.64-0.87) and 0.90 (95% CI: 0.84-0.94) in intrathoracic staging on a per-node basis. For detecting extrathoracic metastases, the pooled sensitivities and specificities of (18)F-FDG PET/CT were 0.77 (95% CI: 0.47-0.93) and 0.95 (95% CI: 0.92-0.97) for all extrathoracic metastases; 0.91 (95% CI: 0.80-0.97) and 0.98 (95% CI: 0.94-0.99) for bone metastases. (18)F-FDG PET/CT is beneficial in detecting lymph node metastases and extrathoracic metastases although PET/CT showed low sensitivity in detecting brain metastases. (18)F-FDG PET/CT confers significantly higher sensitivity and specificity than contrast-enhanced CT (both p < 0.01) and higher sensitivity than (18)F-FDG PET in staging NSCLC (p < 0.05).

Use of Positron Emission Tomography in Initial Staging of Nonsmall Cell Lung Carcinoma: A Regional Teaching Hospital Experience

The ability to accurately diagnose mediastinal lymph node involvement is significantly important in patients with nonsmall cell lung cancer (NSCLC). Positron emission tomography (PET) imaging has become a standard technique to assess lymph node involvement in patients with NSCLC. The purpose of this study is to evaluate the accuracy of PET scan imaging as a mediastinal staging tool in patients with NSCLC at our regional teaching institution. We performed a single-institution, retrospective review of patients diagnosed with NSCLC from January 1, 2006, through December 31, 2007. We included only those patients who underwent computed tomography (CT), PET, and pathologic assessment of mediastinal lymph nodes. Using pathologic assessment as the criterion standard, the overall accuracy, sensitivity, specificity, and positive and negative predictive values of CT and PET were calculated. One hundred seventeen patients were identified for inclusion in the study. The overall accuracy was 81.2 per cent for CT and 91.5 per cent for PET. Sensitivity was 42.1 per cent for CT and 52.6 per cent for PET. Specificity was 88.8 per cent for CT and 99.0 per cent for PET. Positive predictive values were 42.1 per cent for CT and 90.9 per cent for PET; negative predictive values were 88.8 per cent for CT and 91.5 per cent for PET. False-negative result rates were 9.4 per cent for CT and 7.7 per cent for PET; false-positive result rates were 9.4 per cent for CT and 0.9 per cent for PET. Our analysis confirms the use of PET scan imaging in the staging of patients with NSCLC at a regional teaching institution.

(18)FDG-PET/CT for detection of mediastinal nodal metastasis in non-small cell lung cancer: a meta-analysis

BACKGROUND

We performed a meta-analysis to evaluate the role of (18)F-fluorodeoxyglucos -e positron emission tomography/computed tomography ((18)FDG-PET/CT) in detecting mediastinal nodal metastasis in patients with non-small cell lung cancer (NSCLC).

METHODS

Studies about (18)FDG-PET/CT for detecting mediastinal nodal metastasis in patient with NSCLC were systematically searched in the MEDLINE, EMBASE, and EBM Review databases from January 1, 2000 to July 26, 2011. A software called "Meta-Disc" was used to obtain pooled estimates of sensitivity, specificity, positive likelihood ratio (PLR), and negative likelihood ratio (NLR), respectively. We also calculated summary receiver operating characteristic (SROC) curves, and the Q* index.

RESULTS

20 articles fulfilled all inclusion criteria (3028 eligible patients). The pooled sensitivity, and specificity with 95% confidence interval for PET/CT on a per-patient analysis were 0.719 (0.683-0.753), and 0.898 (0.882-0.912). Corresponding values for PET/CT on a per-nodal-station analysis were 0.610 (0.582-0.636), 0.924 (0.918-0.930). The Q* index estimates under SROC were 0.8464 and 0.8067, respectively.

CONCLUSIONS

(18)FDG-PET/CT had more specificity but less sensitivity for mediastinal nodal metastasis in patients with NSCLC.

Diagnostic performance of integrated positron emission tomography/computed tomography for mediastinal lymph node staging in non-small cell lung cancer: a bivariate systematic review and meta-analysis

INTRODUCTION

Accurate clinical staging of mediastinal lymph nodes (MLNs) of patients with non-small cell lung cancer (NSCLC) is important in determining therapeutic options and prognoses. Integrated positron emission tomography and computed tomography (PET/CT) scanning is becoming widely used for MLN staging in patients with NSCLC. We performed a bivariate meta-analysis to determine the pooled sensitivity (SEN) and specificity (SPE) of this imaging modality.

METHODS

The PubMed/MEDLINE, Embase, and SpringerLink databases were searched for articles related to PET/CT for MLN staging in patients with NSCLC. SEN and SPE were calculated for every study. Hierarchical summary receiver operating characteristic curves were used to summarize overall test performance and assess study quality. Potential between-study heterogeneity was explored by subgroup analyses.

RESULTS

Fourteen of 330 initially identified reports were included in the meta-analysis. When we did not consider the unit of analysis, the pooled weighted SEN and SPE were 0.73 (95% confidence interval [CI]: 0.65-0.79) and 0.92 (95% CI: 0.88-0.94), respectively. In the patient-based data analysis, the pooled weighted SEN was 0.76 (95% CI: 0.65-0.84) and the pooled weighted SPE was 0.88 (95% CI: 0.82-0.92). In the MLN-based data analysis, the pooled SEN was 0.68 (95% CI: 0.56-0.78) and the pooled SPE was 0.95 (95% CI: 0.91-0.97).

CONCLUSIONS

Integrated PET/CT is a relatively accurate noninvasive imaging technique, with excellent specificity for MLN staging in patients with NSCLC. Nevertheless, current evidence suggests that we should not depend on the results of PET/CT completely for MLN staging in patients with NSCLC.

Additional value of FDG-PET to contrast enhanced-computed tomography (CT) for the diagnosis of mediastinal lymph node metastasis in non-small cell lung cancer: a Japanese multicenter clinical study

OBJECTIVE

This study was a controlled multicenter clinical study to verify the diagnostic effects of additional FDG-PET to contrast-enhanced CT for mediastinal lymph node metastasis in patients with operable non-small cell lung cancer (NSCLC).

METHODS

NSCLC patients with enlarged mediastinal lymph nodes (short diameter, 7-20 mm), confirmed using contrast-enhanced CT, were examined using FDG-PET to detect metastases prior to surgery. The primary endpoint was the accuracy for concomitantly used CT and FDG-PET showing the additional effects of FDG, compared with CT alone. The secondary endpoints were the clinical impact of FDG-PET on therapeutic decisions and adverse reaction from FDG administration. The images were interpreted by investigators at each institution. Moreover, blinded readings were performed by an image interpretation committee independent of the institutions. The gold standard was the pathological diagnosis determined by surgery or biopsy after PET, and patients in whom a pathological diagnosis was not obtained were excluded from the analysis.

RESULTS

Among 99 subjects, the results for 81 subjects eligible for analysis showed that the accuracy improved from 69.1% (56/81) for CT alone to 75.3% (61/81) for CT + PET (p = 0.404). These findings contributed to treatment decisions in 63.0% (51/81) of the cases, mainly with regard to the selection of the operative procedure. The results of the image interpretation committee showed that the accuracy improved from 64.2% (52/81) (95% CI 52.8-74.6) for CT to 75.3% (61/81) (95% CI 64.5-84.2) for CT + PET. The accuracy for 106 mediastinal lymph nodes improved significantly from 62.3% (66/106) (95% CI 52.3-71.5) for CT to 79.2% (84/106) (95% CI 70.3-86.5) for CT + PET (p < 0.05). We found that no serious adverse drug reactions appeared in any of the 99 patients who received FDG, except for transient mild outliers in the laboratory data for two patients.

CONCLUSIONS

The addition of FDG-PET to contrast-enhanced CT imaging for the staging of NSCLC improved the diagnostic accuracy for mediastinal lymph node metastasis. FDG-PET improved the precision of the staging of NSCLC and contributed to the surgical decisions.

[Utility of PET/CT for mediastinal staging of non-small cell lung cancer in stage III (N2)]

PURPOSE

To evaluate the accuracy of integrated positron emission tomography with (18)F-fluoro-2-deoxy-D-glucose (FDG) and computed tomography (PET/CT) in mediastinal lymph node staging in patients with potentially operable (N2) non-small cell lung cancer (NSCLC) and to ascertain the role of invasive staging in verifying positron emission tomography (PET)/computed tomography (CT) results.

MATERIAL AND METHODS

A retrospective study of consecutive patients with pathologically-proven NSCLC and N2 staging by enhanced CT was performed. A PET/CT scan was performed for all the patients. Lymph node staging was pathologically confirmed when it was possible or by consensus in the Thoracic Cancer Committee. Sensitivity, specificity, negative predictive value and positive predictive value of PET/CT in N2 cases were determined.

RESULTS

A total of 34 patients with N2 by CT were evaluated. PET/CT showed N2 in 30 patients. Discrepancies were found in four patients, two patients were classified as N1 in PET/CT and two patients as N0. Lymph node staging was pathologically confirmed in 20 patients. No false positives were found in PET/CT study. Sensitivity was 94.7%, specificity and positive predictive values were 100% and negative predictive value was 50%.

CONCLUSIONS

Our data show that integrated PET/CT provides high sensitivity and positive predictive value in mediastinal nodal staging of NSCLC patients. Therefore, in patients with potentially resectable lung cancer, neoadjuvant chemotherapy candidate, mediastinoscopy could be reserved for restaging after induction therapy.

Is there any maximum standardized uptake value variation among positron emission tomography scanners for mediastinal staging in non-small cell lung cancer?

The maximum standardized uptake value (SUV(max)) varies among positron emission tomography-integrated computed tomography (PET/CT) centers in the staging of non-small cell lung cancer. We evaluated the ratio of the optimum SUV(max) cut-off for the lymph nodes to the median SUV(max) of the primary tumor (ratioSUV(max)) to determine SUV(max) variations between PET/CT scanners. The previously described PET predictive ratio (PPR) was also evaluated. PET/CT and mediastinoscopy and/or thoracotomy were performed on 337 consecutive patients between September 2005 and March 2009. Thirty-six patients were excluded from the study. The pathological results were correlated with the PET/CT findings. Histopathological examination was performed on 1136 N2 lymph nodes using 10 different PET/CT centers. The majority of patients (group A: 240) used the same PET/CT scanner at four different centers. Others patients were categorized as group B. The ratioSUV(max) for groups A and B was 0.18 and 0.22, respectively. The same ratio for centers 1, 2, 3 and 4 was 0.2, 0.21, 0.21, and 0.23, respectively. The optimal cut-off value of the PPR to predict mediastinal lymph node pathology for malignancy was 0.49 (likelihood ratio +2.02; sensitivity 70%, specificity 65%). We conclude that the ratioSUV(max) was similar for different scanners. Thus, SUV(max) is a valuable cut-off for comparing-centers.

Positron emission tomography for benign and malignant disease

Functional imaging using radiolabeled probes that specifically bind and accumulate in target tissues has improved the sensitivity and specificity of conventional imaging. Fluorodeoxyglucose (FDG)-positron emission tomography (PET) has shown improved diagnostic accuracy in differentiating benign from malignant lesions in the setting of solitary pulmonary nodules. FDG-PET has become useful in preoperative staging of patients with lung cancer, and is being tested with many other malignancies for its ability to change patient management. This article provides an overview of the current status of FDG-PET and presents the challenges of moving toward routine use.

Imaging and 'omic' methods for the molecular diagnosis of cancer

Molecular imaging methods can noninvasively detect specific biological processes that are aberrant in cancer, including upregulated glycolytic metabolism, increased cellular proliferation and altered receptor expression. PET using the glucose analogue 18F-fluoro-2-deoxyglucose, which detects the increased glucose uptake that is a characteristic of tumor cells, has been widely used in the clinic to detect tumors and their responses to treatment; however, there are many new PET tracers being developed for a wide range of biological targets. Magnetic resonance spectroscopy (MRS), which can be used to detect cellular metabolites, can also provide prognostic information, particularly in brain, breast and prostate cancers. An emerging technique, which by hyperpolarizing 13C-labeled cell substrates dramatically enhances their sensitivity to detection, could further extend the use of MRS in molecular imaging in the clinic. Molecular diagnostics applied to serum samples or tumor samples obtained by biopsy, can measure changes at the individual cell level and the underlying changes in gene or protein expression. DNA microarrays enable high-throughput gene-expression profiling, while mass spectrometry can detect thousands of proteins that may be used in the future as biomarkers of cancer. Probing molecular changes will aid not only cancer diagnosis, but also provide tumor grading, based on gene-expression analysis and imaging measurements of cell proliferation and changes in metabolism; staging, based on imaging of metastatic spread and elevation of protein biomarkers; and the detection of therapeutic response, using serial molecular imaging measurements or monitoring of serum markers. The present article provides a summary of the molecular diagnostic methods that are currently being trialed in the clinic.