FDG PET/CT and Mediastinal Nodal Metastasis Detection in Stage T1 Non-Small Cell Lung Cancer: Prognostic Implications

OBJECTIVE: We aimed to compare the prognoses of patients with pathologically true negative (P-TN) N2 and PET/CT false negative (FN) results in stage T1 non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: Our institutional review board approved this retrospective study with a waiver of informed consent. The study included 184 patients (124 men and 60 women; mean age, 59 years) with stage T1 NSCLC who underwent an integrated PET/CT and surgery. After estimating the efficacy of PET/CT for detecting N2 disease, we determined and compared disease-free survival (DFS) rates in three groups (P-TN [n = 161], PET/CT FN [n = 12], and PET/CT true positive [TP, n = 11]) using the Kaplan-Meier analysis and log-rank test. RESULTS: Pathologic N2 disease was observed in 23 (12%) patients. PET/CT had an N2 disease detection sensitivity of 48% (11 of 23 patients), a specificity of 95% (153 of 161), and an accuracy of 89% (164 of 184). The 3-year DFS rate in the PET/CT FN group (31%, 95% confidence interval [CI]; 13.6-48.0%) was similar to that of the TP group (16%, 95% CI; 1.7-29.5%) (p = 0.649), but both groups had significantly shorter DFS rates than the P-TN group (77%, 95% CI; 72.0-81.2%) (p < 0.001). CONCLUSION: The PET/CT shows a high specificity, but low sensitivity for detecting N2 disease in stage T1 NSCLC. Patients with PET/CT FN N2 disease have survival rates similar to PET/CT TP N2 disease patients, which are both substantially shorter than the survival rate of P-TN patients.

The Usefulness of Thin-Section Spiral CT in the Evaluation of Mediastinal Lymph Node Metastasis from Non-Small Cell Lung Cancer: AProspective Study and Comparison with Thick-Section Spiral CT

PURPOSE: To compare the accuracy of thick-and thin-section spiral CT and to determine whether, in diagnosing mediastinal lymph node metastasis from non-small cell lung cancer, the latter is superior to the former. MATERIALS AND METHODS: Between March 1997 and March 1998, 51 patients with pathologically proven non-s-mall cell lung cancer underwent thoracotomy with full nodal dissection. Thick- and thin-section spiral CT were performed in all patients, with a mean interval of 14 days. The former was performed with 10 mm thick-ness and 10 mm interval, and the latter with 3 mm thickness and 3 mm interval. Mediastinal lymph nodes were localized according to the lymph node mapping scheme of the American Thoracic Society and were considered positive for metastasis if they exceeded 10 mm in short-axis diameter. RESULTS: A total of 227 mediastinal nodal stations in 51 patients were obtained. Of these, 188 stations included in thin-section spiral CT were analyzed and the prevalence of ediastinal nodal metastasis was found to be 10%. On a station-by-station basis, and for thick-and thin-section spiral CT, respectively, the overall sensitivi-ties of mediastinal lymph node metastasis were 32% and 53% (p .05). Although there were no statistically significant differences in sensitivity and specificity according to nodal station, thin-section spiral CT tended to be superior to the thick-section type for stations 7 and 10R in terms of sensitivity, and for stations 4L and 5 in terms of specificity. CONCLUSION: Thin-section spiral CT was more sensitive than thick-section spiral CT is the evaluation of medi-astinal lymph node metastasis from non-small cell lung cancer. This may be due to the higher resolution of the former and its ability to discriminate between lymph node and vessel.

Accuracy of CT in Detection of Mediastinal Lymph Node Metastasis in Patients with Lung Cancer: A ProspectiveStudy

PURPOSE: To determine the accuracy of CT in the evaluation of mediastinal nodal metastases of non-small celllung cancer. MATERIALS AND METHODS: Between November 1994 and June 1997, 178 patients with non-small cell lung cancer underwent thoracotomy and full nodal sampling. The results of preoperative CT scanning and of pathologicexamination of regional lymph node metastases were compared. Each scan was prospectively interpreted by one chestradiologist. Mediastinal lymph nodes were localized according to the lymph node mapping scheme of the AmericanThoracic Society and were considered abnormal if they exceeded 10mm in short-axis diameter. All accessible nodeswere either removed or sampled during thoracotomy. RESULTS: Of the 178 non-small cell lung cancers, 90 weresquamous cell carcinoma, 60 were adenocarcinoma, 13 were brochioloalveolar carcinoma, ten were large cellcarcinoma, and five were others (basaloid, 1; sarcomatoid, 1; spindle cell, 1; adenosquamous cell, 2). A total of615 mediastinal nodal stations were obtained. The sensitivity of CT for the diagnosis of mediastinal nodemetastasis on a station-by-station basis was 21%, with a specificity of 93% (squamous cell carcinoma: 21% and 91%;adenocarcinoma: 20% and 95%, respectively). Sensitivities were higher for groups 7 and 5. In 13 bronchioloalveolarcarcinomas, no lymph node metastasis was found on either CT or pathologic examination. The sensitivity of CT forthe diagnosis of mediastinal node metastasis on a per-patient basis was 43%, with a specificity of 83%. CONCLUSION: Because of the relative insensitivity of CT for the detection of mediastinal lymph node metastasis, nodalsampling with mediastinoscopy or thoracotomy is essential in the staging work-up of non-small cell lung cancerother than bronchioloalveolar carcinoma.

Mucinous and Nonmucinous Type of Bronchioloal veolar Carcinoma: Difference in CT Findings

PURPOSE: To search for CT findings which helpfully differentiate mucinous from nonmucinousbronchi-oloalveolar carcinoma and to assess the difference in stages between the two types of tumors. Twenty-two patients with pathologically proven bronchioloalveolar carcinoma (BAC) were included inthis study. On the basis of CT findings, tumors were classified as either solitary or multiple and as eithermass/nodule, consolidation, or mixed type. CT stages of the tumors were determined by two radiologists andconclusions were reached by consensus. RESULTS: Twelve patients had nonmucinous BACs and ten had mucinous BACs.Among the ten cases of mucinous BAC, six were solitary and four were multiple. These were mass/nodule (n=3),consolidation (n=5), and mixed pattern (n=2). In contrast, among the twelve cases of nonmucinous BAC, six weresolitary and six were multiple. All were mass/nodule, except for one mixed type. Among the mucinous BACs, threewere operable and seven (above stage IIIa) were inoperable. Among the nonmucinous BACs, four were operable andeight were inoperable. CONCLUSION: Consolidation was more common in mucinous BAC and mass/nodule was more commonin non-mucinous BAC (p0.05).

CT Findings of Pleural Dissemination from Lung Cancer

PURPOSE: The purpose of our study was to identify the CT findings that help detect pleural dissemination from lung cancer and to evaluate the usefulness of selected diagnostic criteria. MATERIALS AND METHODS: After a computerized database search of 606 patients who had undergone thoracotomy for primary lung cancer, 23 patients were identified as h aving surgically documented pleural dissemination. From the same database, 50 patients without pleural dissemination during thoracotomy were randomly selected as controls. Preoperative CT scans and medical records were rev i ewed retrospectively, and findings were compared between the two groups. RESULT: One or more of three types of pleural thickening (plaque-like, nodular, and fissural) were identified on CT as the most discriminating finding (sensitivity, 74 % ; specificity, 60 %; p = 0.007). The following findings were also significantly discriminating (p<0.05): contiguity of primary tumor with the pleural surface as seen on CT; adenocarcinoma in cell type; and a peripheral tumor defined as one in which bronchoscopy revealed no endobronchial lesion. The use of combinations of these findings in addition to pleural thickening rendered diagnostic criteria more specific at the cost of the sensitivity. CONCLUSION: During preoperative CT evaluation of lung cancer, the recognition of subtle pleural thickening helps detect pleural dissemination. The likelihood that subtle pleural thickening represents pleural dissemination is increased when a primary tumor is contiguous with the pleural surface, is an adenocarcinoma, or is peripherally located.

Evaluation of Mediastinal Lymph Node Metastasis in Lung Cancer: Factors influencing the Diagnostic Accuracy ofCT

PURPOSE: To evaluate factors influencing the CT assessment of mediastinal lymph node metastasis in patientswith non-small cell lung cancer. MATERIALS AND METHODS: CT scans of 198 patients who had undergone thoracotomyand mediastinal lymph node dissection for non-small cell lung cancer were retrospectively evaluated using a sizecriterion of > or = 10mm in the short axis. To evaluate the accuracy of CT in diagnosing lymph node metastasis on anodal station-by-station basis, CT and pathological results were correlated. Analysis included a comparison of thesensitivity and specificity of CT according to 1) cell type of tumor, squamous cell carcinoma versusadenocarcinoma (excluding bronchioloalveolar cell carcinoma) ; 2) histologic differentiation;3) tumor size;4)central and peripheral of the tumor;5) the presence or absence of obstructive pneumonitis and/or atelectasis;6)the presence or absence of prior granulomatous disease. RESULTS: The overall sensitivity, Specificity, positive predictive value, and negative predictive value of CT in diagnosing mediastinal lymph node metastasis were 65%,84%, 43%, and 93%, respectively. Sensitivity for squamous cell carcinoma (72%) was significantly higher than thatfor adenocarcinoma(44%)(p<0.01). Higher specificities were noted in patients without obstructive pneumonitisand/or atelectasis(91% versus 75%)(P<0.01), and with a peripherally located tumor (90% versus 82%)(P<0.01).sensitivity and specificity were not appreciably altered by other variables. CONCLUSION: In the CT assessment ofmediastinal lymph node metastasis the cell type of adenocarcinoma adversely affected sensitivity, with a highfrequency of normal-sized metastatic nodes. Obstructive pneumonitis caused by central tumor adversely affectedspecificity with the frequent occurrence of hyperplastc nodes.

Chest Wall and Fissural Invasion of Peripheral Lung Cancer: Evaluation with HRCT

PURPOSE: We studied the accuracy of high resolution computed tomography in staging chest wall/fissural invasion of peripheral lung cancer. MATERIALS AND METHODS: HRCT findings in 27 patients with suspected chest wall (n=18) or fissural (n=16) invasion of peripheral lung cancer were correlated with surgical and pathologic findings. The HRCT images were restrospectively evaluated for pleural thickenings adjacent to mass, maximal contact length (cm) between mass and chest wall/fissure, angle between the mass and chest wall/fissure, ratio of maximal contact to mass diameter, abnormality of extrapleural fat layer, mass extension across the fissure and fissural irregularity adjacent to mass. Various CT findings and the presence or absence of chest pain were correlated with surgical and pathologic findings. RESULTS: For the evaluation of chest wall invasion, abnormality of extraphleural fat layer was the most useful finding (sensitivity 100 %, specificity 36 %, accuracy 61 %). The remaining HRCT findings proved to have high sensitivity but low specificity, and a high false positive rate. For chest pain, sensitivity was 43 % and specificity, 82 %. In cases without chest pain, the positive predictive value of extraphleural fat abnormality was 44 % ; in the absence of chest pain and extrapleural fat abnormality,positive predictive value was zero. The evaluation of transfissural tumor invasion using variable HRCT findings proved to be accurate, especially when the criteria of mass extension across the fissure and fissural irregularity adjacent to the mass were used (accuracy 81 % and 75 %, respectively). CONCLUSION: Using the finding of 'extrapleural fat abnormeality', HRCT was accurate in the staging of chest wall invasion and its predictability was betten than that of other results obtained with conventional CT. Chest pain had high specificity but low prevalence, and extrapleural fat abnormality was more valuable in cases without chest pain. HRCT proved to be accurate in the evaluation of transfissural invasion of lung cancer using the findings 'fissural cross' and 'fissural irregularity'.