Advantages of positron emission tomography over computed tomography in mediastinal staging of non-small cell lung cancer

BACKGROUND: New treatment algorithms in early stage non-small cell lung cancer (NSCLC) involving preoperative chemotherapy require accurate clinical staging of the mediastinum. This study compares the accuracy of 2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) scanning with that of computed tomography (CT) scanning in the clinical staging of non-small cell lung cancer. MATERIALS AND METHODS: A retrospective review was performed on 52 patients with NSCLC who were evaluated with both CT and PET scans. All patients had their mediastinal lymph nodes sampled by mediastinoscopy or at the time of thoracotomy for pulmonary resection. Each imaging study was evaluated separately and correlated with histopathologic results. RESULTS: For detecting mediastinal metastases the sensitivities of PET and CT scans were 67 and 50%, respectively; specificities were 91 and 65%, respectively; accuracies were 88 and 63%, respectively; positive predictive values were 50 and 16%, respectively; negative predictive values were 95 and 88%, respectively. PET scans were significantly better than CT scans at detecting mediastinal metastases (PET, 4/8; CT, 3/19) (P = 0.01). CONCLUSIONS: PET scanning is superior to CT scanning for clinical staging of the mediastinum in NSCLC. A more confident decision regarding stratification of patients into current treatment algorithms can be made when the decision is based on PET scanning rather than the current "gold standard" of CT scanning.     

Lymph node staging in non-small cell lung cancer: evaluation by [18F]FDG positron emission tomography (PET)

BACKGROUND: A study was undertaken to investigate the accuracy of positron emission tomography (PET) with 2-[18F]-fluoro-2-deoxy-D- glucose (FDG) in the thoracic lymph node staging of non-small cell lung cancer (NSCLC). METHODS: Forty six patients with focal pulmonary tumours who underwent preoperative computed tomographic (CT) and FDG- PET scanning were evaluated retrospectively. Thirty two patients had NSCLC and 14 patients had a benign process. The final diagnosis was established by means of histopathological examination at thoracotomy, and the nodal classification in patients with lung cancer was performed by thorough dissection of the mediastinal nodes at surgery. RESULTS: FDG-PET was 80% sensitive, 100% specific, and 87.5% accurate in staging thoracic lymph nodes in patients with NSCLC, whereas CT scanning was 50% sensitive, 75% specific, and 59.4% accurate. The absence of lymph node tumour involvement was identified by FDG-PET in all 12 patients with NO disease compared with nine by CT scanning. Lymph node metastases were correctly detected by FDG-PET in three of five patients with N1 disease compared with two by CT scanning, in nine of 11 with N2 disease compared with six by CT scanning, an in all four with N3 nodes compared with two by CT scanning. CONCLUSIONS: FDG-PET provides a new and effective method for staging thoracic lymph nodes in patients with lung cancer and is superior to CT scanning in the assessment of hilar and mediastinal nodal metastases. With regard to resectability, FDG-PET could differentiate reliably between patients with N1/N2 disease and those with unresectable N3 disease.     

Comparative efficacy of positron emission tomography with FDG and computed tomographic scanning in preoperative staging of non-small cell lung cancer

OBJECTIVE: To determine the sensitivity, specificity, and accuracy of positron emission tomography with 2-fluorine-18-fluorodeoxyglucose (PET-FDG) in the preoperative staging (N and M staging) of patients with lung cancer. The authors wanted to compare the efficacy of PET scanning with currently used computed tomography (CT) scanning. MATERIALS AND METHODS: Results of whole-body PET-FDG imaging and CT scans were compared with histologic findings for the presence or absence of lymph node disease or metastatic sites. Sampling of mediastinal lymph nodes was performed using mediastinoscopy or thoracotomy. RESULTS: PET-FDG imaging was significantly more sensitive, specific, and accurate for detecting N disease than CT. PET changed N staging in 35% and M staging in 11% of patients. CT scans helped in accurate anatomic localization of 6/57 PET lymph node abnormalities. CONCLUSION: PET-FDG is a reliable method for preoperative staging of patients with lung cancer and would help to optimize management of these patients. Accurate lymph node staging of lung cancer may be ideally performed by simultaneous review of PET and CT scans.     

Bronchogenic carcinoma: incidence of metastases to normal sized lymph nodes.

BACKGROUND--The incidence of metastases to mediastinal lymph nodes was evaluated in patients with normal sized mediastinal nodes on the computed tomographic (CT) scan who underwent thoracotomy. The use of hilar lymph nodes in predicting mediastinal lymph node metastases was also assessed. METHODS--Ninety patients with non-small cell lung cancer who later underwent thoracotomy wer prospectively examined by CT scanning. Lymph nodes with a short axis diameter of 10 mm or more were considered abnormal. RESULTS--Mediastinal lymph node metastases were present at thoracotomy in 19 patients (21%). In 14 these lymph node metastases were misdiagnosed because the nodes were normal in size on the CT scan. In only one of the 19 patients with N2 nodes was an N1 lymph node enlarged, and four of the 19 patients with N2 nodes had metastases to these mediastinal nodes without N1 disease ("skipping metastases"). CONCLUSIONS--Metastases in normal sized nodes seen on the CT scan are a major problem in staging. Hilar lymph nodes did not help to predict reliably the presence or absence of metastases to the mediastinal lymph nodes.     

Study of mediastinal lymph nodes in lung cancer using transesophageal ultrasonography]

Evaluation of mediastinal lymph nodes in patients with lung cancer is fundamental for their treatment and prognosis. Chest computed tomography (CT) is presently the most utilized diagnostic modality. In recent years endoscopic ultrasound (EUS) is being employed for this purpose. We retrospectively compared the results of CT and EUS staging of 35 selected patients with postsurgical stage. A total of 175 lymph node sites were examined. Results CT vs EUS were as follows: specificity 92% vs 98%, sensitivity 88% vs 84%, positive predicted accuracy 80% vs 96%, negative predicted accuracy 95% vs 94%, overall accuracy 92% vs 95%. The region most accessible by EUS evaluation were the paraesophageal lymph nodes; the most difficult were the right superior mediastinal nodes which cannot be imaged for anatomic reasons. EUS not only allows one to arrive at correct diagnosis with less false positive results, but also permits evaluation of lymph nodes which are not enlarged. We think that EUS, in combination with CT, is an appropriate modality for staging of mediastinal lymph nodes in patients with lung cancer.     

支气管内超声引导针吸活检术在非小细胞肺癌术前分期中的临床应用

目的探讨支气管内超声引导针吸活检术(EBUS-TBNA)在非小细胞肺癌纵隔淋巴结分期中的应用价值。 方法2010年9月至2012年9月,北京大学人民医院利用EBUS-TBNA对术前确诊或CT扫描高度怀疑非小细胞肺癌且伴有纵隔淋巴结肿大(N₂站淋巴结短径≥1.0cm,或N₁站淋巴结短径≥1.0cm且N₂多站短径≥0.5cm者),有手术切除可能,术前无放、化疗史的126例患者进行纵隔淋巴结分期。最终入组82例非小细胞肺癌患者。 结果该组82例患者,经EBUS-TBNA检查证实纵隔淋巴结转移(阳性)者54例,未见纵隔淋巴结转移(阴性)者28例。EBUS-TBNA在该组肺癌术前纵隔淋巴结分期中的敏感度、特异度和准确性分别为94.7%(54/57)、100.0%(25/25)和96.3%(79/82),阳性预测值及阴性预测值分别为100.0%(54/54)和89.3%(25/28)。而CT对于本组患者纵隔淋巴结分期中的敏感度、特异度和准确性分别为98.2%(55/56)、38.5%(10/26)和79.3%(65/82),阳性预测值及阴性预测值分别为77.5%(55/71)和90.9%(10/11)。CT在术前纵隔淋巴结分期中的假阳性率为22.5%(16/71)。全组中,16例(19.5%)肺癌患者因EBUS-TBNA病理结果改变了治疗策略。 结论EBUS-TBNA用于非小细胞肺癌纵隔淋巴结分期的敏感性、特异性和准确性较高。EBUS-TBNA可以作为非小细胞肺癌术前分期、指导治疗策略的检查手段。     

Factors associated with false-positive staging of lung cancer by positron emission tomography

BACKGROUND: Positron emission tomography imaging is gaining popularity as a noninvasive staging tool in non-small cell lung cancer. Nonmalignant processes can also affect radio-tracer uptake. This study seeks to identify factors associated with false-positive staging of mediastinal metastases. METHODS: A retrospective review was performed of 100 patients with early stage non-small cell lung cancer referred for positron emission tomography scan evaluation. All had pathologic confirmation of their disease. Positron emission tomography scans, radiology records, operative reports, and pathology results were reviewed. Patients with positron emission tomography scans interpreted as positive for mediastinal involvement and negative pathology at operation were selected. RESULTS: Seven patients were found to have a false-positive positron emission tomography evaluation for mediastinal metastases. All but 1 patient had a concurrent inflammatory process or an anatomic factor associated with the false positive. The sensitivity and specificity in detecting involved mediastinal nodes was 87.5% and 90.7%, respectively. The negative predictive value was 95.8%. CONCLUSIONS: Although positron emission tomography has been established as an accurate modality to stage non-small cell lung cancer, false-positive evaluation of mediastinal metastases can occur in the setting of concurrent inflammatory lung diseases or for centrally located tumors. Pathologic evaluation of mediastinal disease should be pursued whenever suggested by a positive positron emission tomography scan especially in the face of those factors described.     

FDG-PET imaging for lymph node staging and pathologic tumor response after neoadjuvant treatment of non-small cell lung cancer.

PURPOSE: A number of studies have demonstrated that 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is effective for staging of lung cancer. However, the efficacy of FDG-PET for staging lung cancer after neoadjuvant treatment is still controversial. This study compared FDG-PET and computed tomography (CT) for lung cancer staging, and evaluated the ability of the two methods to predict the pathologic response of the primary tumor to neoadjuvant treatment. PATIENTS AND METHODS: Twenty-two patients who underwent neoadjuvant treatment followed by surgery were investigated. Eighteen patients received chemoradiotherapy and four patients received chemotherapy only. One hundred and three lymph node stations in the 22 patients were evaluated by FDG-PET and CT. The pathologic responses of the tumors were compared by FDG-uptake and tumor size on CT for the 15 patients who underwent FDG-PET and CT both before and after neoadjuvant treatment. RESULTS: There was no significant difference in the ability of FDG-PET or CT to predict residual viable tumor. Although positive predictive value by FDG-PET (0.29) was lower than that by CT (0.64) (p=0.04) in the mediastinal lymph nodes, there were no statistically significant differences in the other results of lymph nodes by FDG-PET and CT. Both decrease in FDG-uptake and decrease in tumor size by CT after neoadjuvant treatment correlated significantly with pathologic response in the 15 patients (p=0.003 and 0.009, respectively). CONCLUSION: FDG-PET did not appear to offer any advantages over CT for lymph node staging or for predicting the pathologic response after neoadjuvant treatment of non-small cell lung cancer.     

The value of computed tomography in staging bronchogenic carcinoma: a changing role for mediastinoscopy

Forty-one patients underwent operative staging for bronchogenic carcinoma following computed tomography of the mediastinum between August, 1982, and March, 1984. Twenty-seven patients were classified as Stage I preoperatively; in 2 of them, positive mediastinal nodes were found at thoracotomy. For the 14 patients in whom positive nodes had been identified by computed tomographic (CT) scanning, staging was unchanged as a result of the findings at mediastinoscopy or thoracotomy or both. In this series, computed tomography had a sensitivity of 89%, a specificity of 100%, and an overall accuracy rate of 95%. We conclude that mediastinoscopy is not needed in patients without evidence of mediastinal nodal enlargement by CT scan; when performed, it should be guided toward those nodes identified as positive.     

The practice of cardiothoracic surgeons in the perioperative staging of non-small cell lung cancer.

BACKGROUND: The treatment and prognosis of non-small cell lung cancer, and assessment of the results of treatment, depend on accurate perioperative staging. The extent to which this is carried out in the United Kingdom is unknown. METHODS: A postal questionnaire survey was undertaken in 1990 to determine the perioperative staging practices of cardiothoracic surgeons in the United Kingdom. RESULTS: Replies from 77 surgeons, who between them performed about 4833 pulmonary resections a year for lung cancer, were analysed. Forty four per cent of surgeons, operating on 43% of the patients, do not perform computed tomography of the thorax or mediastinal exploration before surgery. They may therefore embark on a thoracotomy for stage III disease. At thoracotomy 45% of surgeons, operating on 40% of patients, do not sample macroscopically normal lymph nodes. They may therefore understage cases as N0/N1 when there is at least microscopic disease in mediastinal lymph nodes. CONCLUSIONS: The staging of lung cancer in the United Kingdom in 1990 appears in many instances to be inadequate. There should be a more organised approach to perioperative staging so that prognosis may be assessed and comparisons between groups of patients can be made.     

Peripheral small-sized (2 cm or less) non-small cell lung cancer with mediastinal lymph node metastasis; clinicopathologic features and patterns of nodal spread

Objective: The diagnosis of small-sized (2 cm or less) non-small cell lung cancer (NSCLC) has increased with the development of computed tomography (CT), whereas unexpected extensive multiple-level mediastinal involvement has been occasionally detected in this small-sized lung cancer. To establish the optimal surgical strategy, we retrospectively analyzed the clinicopathologic features, efficacy of preoperative investigations and lobe specific patterns of nodal spread in small-sized NSCLC with mediastinal involvement. Methods: Among 1550 resected lung cancer cases between 1981 and 2000, 267 (17.2%) had peripheral small-sized NSCLC. Of these, 29 patients (10.8%) with mediastinal lymph node involvement who underwent pulmonary resection and systematic nodal dissection were reviewed. Results: Among 29 patients, 27 patients (93.1%) were adenocarcinoma, and 51.7% (15/29) showed no lymph node enlargement on CT (cN0). Surgical pathology revealed multiple-level mediastinal involvement in 65.5% (19/29) of all patients and 60.0% (9/15) of cN0 patients. All of right upper lobe tumors (n=11) showed multiple-level involvement. Thallium-201 single photon emission computed tomography (201Tl-SPECT) was positive for increased focal uptake in the mediastinum in 72.7% (8/11) of patients. Conclusions: The vast majority of cases were adenocarcinoma, and two thirds of them showed multiple-level mediastinal involvement, even in cN0 patients. We thus recommend to perform systematic nodal dissection or meticulous sampling for accurate intrathoracic staging, especially for right upper lobe tumor. 201Tl-SPECT appears to be more sensitive preoperative investigation for mediastinal metastasis compared with CT scan.     

Factors causing inaccurate staging of mediastinal nodal involvement in non-small cell lung cancer patients staged by positron emission tomography

Despite documented superiority of positron emission tomography over other investigative modalities in the preoperative staging of non-small cell lung cancer, a proportion of patients will have an inaccurate staging of their mediastinal nodes. The aim of this retrospective review is to analyse the clinicopathological factors responsible for inaccurate nodal staging by integrated PET-CT. A total of 100 consecutive patients with histologically proven non-small cell lung cancer underwent staging with PET-CT prior to lung resection. Thirty-three patients, inaccurately staged by PET-CT, were analysed. Univariate analysis identified the following as significant in causing inaccurate nodal staging: history of tuberculosis (P=0.039) and non-insulin dependant diabetes (P=0.014). In multivariate analysis, we have identified the following as independent factors in causing inaccurate staging of mediastinal lymph nodes: rheumatoid arthritis, non-insulin dependent diabetes, history of tuberculosis, presence of atypical adenomatous hyperplasia and pneumonia (P<0.05). The highest rate of inaccuracy in mediastinal nodal staging was in nodal station 4 (11%, P=0.01) followed by station 7 (10%, P=0.02) and station 9 (3.5%, P=0.01). Interpretation of PET-CT staging of the mediastinum in patients with a history of the above should be with caution, as the incidence of false upstaging and down staging in these subgroups is high. Vigilance of such factors may improve the accuracy of PET-CT in staging mediastinal lymph nodes. Histological confirmation should always be sought.     

Endoscopic ultrasound in lung cancer patients with a normal mediastinum on computed tomography

BACKGROUND: Computed tomography (CT) is the most common method of staging lung cancer. We have previously shown endoscopic ultrasound guided fine-needle aspiration (EUS-FNA) to be highly accurate in staging patients with nonsmall cell lung cancer (NSCLC) who have enlarged mediastinal lymph nodes on CT scan. In this study we report the accuracy and yield of EUS-FNA in staging patients without enlarged mediastinal lymph nodes by CT. METHODS: Patients with NSCLC and CT scan showing no enlarged mediastinal lymph nodes (> 1 cm for all nodes except > 1.2 cm for subcarinal) in the mediastinum underwent EUS. Fine needle aspiration was performed on at least one lymph node, if present, in the upper mediastinum, aortopulmonary window, subcarinal, and periesophagus regions. Each specimen was evaluated with on-site cytopathology and confirmed with complete cytopathologic examination. RESULTS: Sixty-nine patients without enlarged mediastinal lymph nodes were evaluated. Endoscopic ultrasound detected malignant mediastinal lymph nodes in 14 of 69 patients as well as other advanced (American Joint Committee on Cancer [AJCC] stage III/IV) in 3 others (1 left adrenal, and 2 with mediastinal invasion of tumor) for a total of 17 of 69 (25%, 95% confidence interval: 16% to 34%) patients. Eleven additional patients were found to have advanced disease by bronchoscopy (2), mediastinoscopy (2), and thoracotomy with mediastinal lymph node dissection (7). The sensitivity of EUS for advanced mediastinal disease was 61% (49% to 75%), and the specificity was 98% (95% to 100%). CONCLUSIONS: Endoscopic ultrasound guided fine needle aspiration can detect advanced mediastinal disease and avoid unnecessary surgical exploration in almost one of four patients who have no evidence of mediastinal disease on CT scan. In addition to previously reported results in patients with enlarged lymph nodes on CT, these data suggest that all potentially operable patients with nonmetastatic NSCLC may benefit from EUS staging.     

Comparison of Integrated Positron Emission Tomography/Computed Tomography and Mediastinoscopy in Mediastinal Staging of Non-Small Cell Lung Cancer: Analysis of 212 Patients

Background : Mediastinal staging is crucial to determine the prognosis and treatment options for patients with non-small cell lung cancer (NSCLC). In this study, we compared the results of integrated positron emission tomography-computerised tomography (PET/CT) with those of mediastinoscopy in mediastinal staging of NSCLC patients. Methods : PET/CT and mediastinoscopy was performed on 250 consecutive patients diagnosed with NSCLC between September 2005 and March 2008. Thirty-eight patients were excluded from the study. Standard cervical mediastinoscopy was performed in all patients, and simultaneous extended cervical mediastinoscopy was performed in 52 patients with left sided lesions. Patients with negative mediastinoscopy underwent resection. The pathological results were correlated with PET/CT findings.

Results : A total of 212 patients (199 male, 13 female; mean age: 58.3 years) were evaluated. In PET/CT analysis 60 true-positive, 45 false-positive, 103 true-negative and 4 false-negative patients were found. The rate of PET/CT positivity of mediastinal lymph nodes was 49.5%. The sensitivity, specificity, positive and negative predictive values and accuracy for PET/CT were 93.8%, 69.6%, 57.1%, 96.3% and 76.9% respectively. The incidence of N2 disease in NSCLC patients with negative mediastinal lymph node uptake on PET/CT was 3.7% (4 of 107). In univariate analysis, right upper lobe tumours were significantly (p < 0.05) more associated with occult N2 disease.

Conclusions : In patients with positive mediastinal lymph node uptake on PET/CT invasive mediastinal staging appears necessary for exact staging. Mediastinoscopy can be omitted in NSCLC patients with negative mediastinal uptake on PET/CT in regions where the rate of PET/CT positivity of mediastinal lymph nodes is high.     

Role of positron emission tomography in mediastinal lymphatic staging of non-small cell lung cancer.

OBJECTIVE: Positron emission tomography (PET) is used increasingly in staging of non-small cell lung cancer (NSCLC) as a non-invasive tool. The role of the PET in mediastinal lymphatic staging of NSCLC is not clear. We aimed to demonstrate the efficacy of PET in determining mediastinal lymphatic metastasis by comparing the results of PET with mediastinoscopy. PATIENTS AND METHODS: We performed PET preoperatively in 170 patients with clinically operable NSCLC between 2004 and 2006. Stations defined as metastasis by PET (SUV(max) >2.5) were recorded. Mediastinoscopy was performed initially in all patients and a total of 687 stations which can be reached with mediastinoscope were sampled (mean 4.04). Forty-three patients with mediastinal metastasis were referred to the oncology clinic for chemotherapy while lung resection and complete mediastinal lymphatic dissection through thoracotomy was performed in the remaining 127 patients. Involvement of mediastinal lymph nodes was verified to compare the sensitivity and specificity of mediastinoscopy and the related PET results. RESULTS: Histopathologic classification of the tumors revealed 79 squamous carcinomas and 58 adenocarcinomas. False positivity rate of PET was 26% (95% CI: 14-38), false negativity was 25% (95% CI: 18-33), sensitivity was 74% (95% CI: 63-86), specificity was 73% (95% CI: 66-82) and accuracy was 74% in mediastinal staging. Negative predictive value of mediastinoscopy was 94% (95% CI: 89-98), positive predictive value 100%, sensitivity 84% (95% CI: 74-94), specificity 100% and accuracy was 95%. CONCLUSION: PET results do not provide acceptable accuracy rates. Mediastinoscopy still remains the gold standard for mediastinal staging of NSCLC, although it cannot reach to all the mediastinal stations.     

Hybrid SPECT-CT: an additional technique for sentinel node detection of patients with invasive bladder cancer

OBJECTIVES: To explore the feasibility of performing lymphoscintigraphy combined with computed tomography (CT) for preoperative detection of sentinel lymph nodes in patients with invasive bladder cancer. MATERIALS: Six consecutive patients scheduled for radical cystectomy underwent lymphoscintigraphy after transurethral injection of Albures-technetium 99m in the detrusor muscle peritumourally both with planar imaging and with single-photon emission computed tomography/CT (SPECT/CT). CT for anatomic fusion was performed directly after the SPECT/CT and both investigations were combined to a fused image. Radical cystectomy started with extended lymphadenectomy and intraoperative detection of sentinel nodes with both Geiger probe and dye marker. The conventional planar lymphoscintigraphies and the fused SPECT/CT were compared with each other and with the outcome of intraoperative sentinel node detection and final histopathologic analyses. RESULTS: The method allowed anatomically detailed preoperative visualisation of 21 sentinel nodes in five of the six patients, whereas planar pictures only visualised two sentinel nodes in two of six patients. Two patients had lymph node metastases and in the other four the nodes were negative. The combined method visualised all metastatic sentinel nodes, whereas planar lymphoscintigraphy detected only one of six node metastases. CONCLUSIONS: The combination of lymphoscintigraphy with CT enhanced preoperative anatomic localisation of sentinel nodes in bladder cancer and aided in the identification of sentinel nodes during surgery. The yield of detected sentinel nodes, both metastatic and nonmetastatic, was markedly increased using the combined method compared to conventional planar lymphoscintigraphy.     

Significance of PET/CT in determining actual TNM staging for patients with various lung cancers

We investigated the difference in TNM stage of lung cancer provided by PET/CT (combining positron emission tomography and computed tomography) as compared with TNM stage obtained with conventional imaging studies (CI) with contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) with iron contrast media. Sixty-seven cases of lung cancer were included in this study. Overall, the rate of correction of TNM staging was 70.1% after PET/CT. The correction rate for each factor was 32.8% in T, 37.3% in N, and 37.3% in M. High rates of correction were observed in small cell lung cancer (SCLC), with 75% (6/8 cases) obtained by PET/CT. When SCLCs were divided into limited disease (n = 6) involving 1 hemithorax, including mediastinal and contralateral hilar lymph nodes, and others (extensive disease, n = 2), the correction rate was as high as 80% for limited disease. In conclusion, PET/CT can provide actual TNM staging and recognition for oncologists in staging, which would not mislead to selection of inadequate subsequent treatment.     

PET staging of mediastinal lymph nodes in thoracic oncology

There is an extensive and growing body of literature about the role of positron emission tomography (PET) in the management of non-small cell lung cancer and esophageal cancer. This article focuses on the use of PET in mediastinal staging of these common thoracic malignancies. PET is the most accurate noninvasive approach to staging mediastinal lymph nodes in non-small cell lung cancer. The role of PET in mediastinal lymph node staging in esophageal cancer is less clear, since it has been largely supplanted by endoscopic ultrasonography. A review of the evidence for and against the use of PET in mediastinal staging is provided and the use of PET in practice is discussed.     

Selective preoperative evaluation for possible N2 disease in carcinoma of the lung

The efficacy of computed tomography and surgical mediastinal exploration in determining tumor resectability were retrospectively evaluated in 92 consecutive patients with non-small cell lung carcinoma. Status of mediastinal nodes was ultimately determined by surgical mediastinal exploration or thoracotomy. Patients were divided into three groups on the basis of chest roentgenography: Group I comprised 30 patients with peripheral T1 or T2 lesions with normal hilar and mediastinal shadows. Only one patient was found to have an involved node. Chest roentgenography had an accuracy rate of 96% and computed tomography, 93%. Thoracotomy is recommended without either computed tomography or surgical mediastinal exploration in this group. Group II comprised 47 patients with T1 or T2 lesions with an abnormal hilus, an abnormal mediastinal shadow, or either the hilus or mediastinum obscured by overlying parenchymal disease. Computed tomography revealed mediastinal nodes 1 cm or greater in size (abnormal node group) in 21 patients (45%) and smaller than 1 cm (normal node group) in 26 patients (55%). Surgical mediastinal exploration was performed in the abnormal node group and involved nodes were found in 17 of 21 patients (81%). In the normal node group, thoracotomy only was performed and no involved nodes were found. Computed tomography is recommended in all patients in Group II. Patients in the normal node group may be subjected to thoracotomy only and those in the abnormal node group should undergo surgical mediastinal exploration as the next diagnostic step before thoracotomy. Group III comprised 15 patients with grossly abnormal mediastinal shadows. Findings from computed tomography were abnormal in all 10 patients in whom it was done. Surgical mediastinal exploration was done in all 15 and yielded abnormal results in 14. It is recommended in this group that computed tomography is unnecessary and surgical mediastinal exploration should be the only diagnostic procedure. Thus, in potentially resectable non-small cell lung carcinoma, the use of computed tomography and surgical mediastinal exploration should be selective and should be determined by appropriate initial interpretation of the chest roentgenogram.