Use of Positron Emission Tomography in Assessing Hidden Extrathoracic Metastasis in Non Small Cell Lung Cancer

IntroductionPositron emission tomography combined with computed axial tomography (PET/CT) is used for staging non small cell lung cancer (NSCLC). This study aims to describe PET/CT findings of unsuspected extrathoracic metastasis when used in mediastinal evaluation of patients with apparently resectable NSCLC.Patients and methodProspective and concurrent study including all NSCLC patients between June 2004 and November 2006 who underwent PET/CT after considering them as candidates for surgery, with resectable disease after bronchoscopy, thorax and abdominal CT, brain CT and bone gammagraphy evaluation, if metastasis at these locations were suspected. Metastasis were confirmed histopathologically or assumed when they had a compatible evolution.ResultsA total of 91 patients with NSCLC underwent PET/CT. In 24 of them (26%) at least one suspicious extrathoracic uptake was seen. In 7 patients (7.7%) those uptakes were NSCLC extrathoracic metastasis hidden from conventional staging. In 3 of these cases (13.1%) extrathoracic uptakes corresponded to metacrhonous tumours or pre-malignant conditions. Benign lesions were found in 12 patients (13.1%), and in 2 cases (2.2%) the uptake origins were undetermined.ConclusionsPET/CT is a complementary diagnosis method for assessing hidden metastases which could modify the therapeutical approach in patients otherwise suitable for surgery.     

Evaluation of fluorine-18-fluorodeoxyglucose whole body positron emission tomography imaging in the staging of lung cancer

BACKGROUND: Surgical resection of lung cancer remains the treatment of choice in appropriately staged disease, but conventional imaging techniques have limitations. Positron emission tomography (PET) may improve staging accuracy. METHODS: We studied whole body and localized thoracic PET in staging lung cancer. Standardized uptake value was calculated for the primary lesion. Ninety-seven patients under consideration for surgical resection were included. PET, computed tomography, and clinical staging were compared to stage at operation, biopsy, or final outcome. Mean follow up was 17.5 months. RESULTS: PET detected all primary lung cancers with two false-positive primary sites. Sensitivity and specificity for N2 and N3 mediastinal disease was 20% and 89.9% for computed tomography and 70.6% and 97% for PET. PET correctly altered stage in 26.8%, nodal stage in 13.4%, and detected distant metastases in 16.5%. PET missed 7 of 10 cerebral metastases. PET altered management in 37% of patients. PET staging (p<0.0001) and standardized uptake value (p<0.001) were the best predictors of time to death apart from operative staging. CONCLUSIONS: PET provides significant staging and prognostic information in lung cancer patients considered operable by standard criteria. Routine use of PET will prevent unnecessary operation and may be cost effective.     

Comparison of the number of pre-, intra- and postoperative lung metastases.

AIM: To compare the number of lung metastases seen preoperatively on computed tomography in patients with a previous history of malignant disease with the number of resected pulmonary nodules and the number of histologically proven lung metastases. PATIENTS AND METHODS: Between 1998 and 2003, we operated on 281 patients with suspected lung metastases. The histology of the primary tumour, the number of preoperatively diagnosed nodules, the number of lesions removed during surgery and the number of histologically confirmed metastases of 276 patients are presented. RESULTS: Resection of lung metastases was performed in 276 patients. The median age was 62 years (21-86 years). The mean number of nodules seen on the CT scan was 1.9 (total: 515 nodules), 2.9 pulmonary lesions were removed (total: 835 nodules) and 2.1 nodules were confirmed as lung metastases (total: 560). In 39%, the number of lesions found and removed during the operation was higher than counted on the preoperative CT scan. These extra nodules found during the operation were confirmed as lung metastases in 16% of all patients. A benign solitary lesion was found in 15.2% of the patients and in 7.9% a primary carcinoma of the lung was diagnosed. In patients with a solitary nodule we found no metastasis in 16.4%, one lung metastasis in 76.7% and more than one lung metastasis in 6.9%. In patients with more than one nodule on the preoperative CT scan, an identical number of lung metastases were histologically confirmed in 35% of the patients, a larger number in 27.4% and a smaller number in 37.6%. CONCLUSIONS: In patients with a previous history of malignant disease, 15.2% of the pulmonary lesions are benign. Video-assisted thoracoscopic surgery (VATS) is a safe diagnostic and therapeutic method for solitary lesions, with little discomfort for the patient. In patients with more than one nodule on the CT scan, manual exploration of the lung is necessary to detect further lesions.     

Results of the American College of Surgeons Oncology Group Z0050 trial: the utility of positron emission tomography in staging potentially operable non-small cell lung cancer

OBJECTIVES: The American College of Surgeons Oncology Group undertook a trial to ascertain whether positron emission tomography with 18F-fluorodeoxyglucose could detect lesions that would preclude pulmonary resection in a group of patients with documented or suspected non-small cell lung cancer found to be surgical candidates by routine staging procedures. METHODS: A total of 303 eligible patients registered from 22 institutions underwent positron emission tomography after routine staging (computed tomography of chest and upper abdomen, bone scintigraphy, and brain imaging) had deemed their tumors resectable. Positive findings required confirmatory procedures. RESULTS: Positron emission tomography was significantly better than computed tomography for the detection of N1 and N2/N3 disease (42% vs 13%, P =.0177, and 58% vs 32%, P =.0041, respectively). The negative predictive value of positron emission tomography for mediastinal node disease was 87%. Unsuspected metastatic disease or second primary malignancy was identified in 18 of 287 patients (6.3%). Distant metastatic disease indicated in 19 of 287 patients (6.6%) was subsequently shown to be benign. By correctly identifying advanced disease (stages IIIA, IIIB, and IV) or benign lesions, positron emission tomography potentially avoided unnecessary thoracotomy in 1 of 5 patients. CONCLUSIONS: In patients with suspected or proven non-small cell lung cancer considered resectable by standard staging procedures, positron emission tomography can prevent nontherapeutic thoracotomy in a significant number of cases. Use of positron emission tomography for mediastinal staging should not be relied on as a sole staging modality, and positive findings should be confirmed by mediastinoscopy. Metastatic disease, especially a single site, identified by positron emission tomography requires further confirmatory evaluation.     

Multimodal treatment of non small cell lung cancer

The primary treatment of lung cancer depends on tumor stage. Chest CT scan and bronchoscopy are used to define the TNM stage and resectability. In case of lung cancer without mediastinal lymph node enlargement or direct mediastinal involvement (clinical stage I-IIb + T3N1) surgical treatment is recommended. The use of adjuvant chemotherapy has to be defined, but will be indicated in stage II and IIIa. Expected 5-year survival achieves 40 to 80 % depending on tumor stage. Exceeds the shorter diameter of mediastinal lymph nodes in chest CT scan more than 1 cm (or in case of positive PET scan) mediastinoscopy is indicated. In case of N2-disease and after tumor response to preoperative chemotherapy (about 60 %) secondary resection of the tumor leads to higher 5-year survival rates (20-40 %) compared to patients without induction therapy (5-20 %). In these patients and after unexpected detection of solitary lymph node metastasis by primary resection adjuvant mediastinal radiotherapy should be added. If the tumor has infiltrated the mediastinum or the upper sulcus (T3/4) and/or mediastinal lymph nodes are obviously tumor burden (e. g. > 3 cm, N2 bulky, N3) radical primary resection may not be possible. In these patients combined radio- and chemotherapy induces a high percentage of tumor regression and can be used before secondary resection (5-year survival 5-20 %). Locally advanced tumors infiltrating the main bronchus close to the carina or the carina itself and tumors with metastases in the same lobe, both without mediastinal lymph node metastases (T3/4N0-1), can be resected by sleeve pneumonectomy and lobectomy with satisfactory results respectively. In patients with resectable lung cancer and no clinical sign of tumor disease (f. e. anemia, weight loss, pain) limited staging procedure with chest CT scan including upper abdomen and bronchoscopy is reasonable. In the remaining patients complete staging is necessary. We recommend an interdisciplinary approach to patients with lung cancer.     

The role of gallium-67 scanning in the clinical staging and preoperative evaluation of patients with carcinoma of the lung.

Gallium-67 scanning was evaluated in 100 patients with proved carcinoma of the lung. It was valuable in separating primary from secondary lung tumors, determining the extent of contralateral hilar or mediastinal lymph node involvement, and detecting distant organ metastases. In addition to multiplane whole-body Ga-67 tomographic scanning, colloid liver scans, bone scans, and computerized axial tomography scans of the brain were obtained to determine the presence of distant metastasis. The gallium scan detected 11 of 12 occult metastases and identified 7 of 7 liver, 9 of 14 brain, 4 of 4 soft tissues, 1 of 4 contralateral lung, and 9 of 11 bone metastases. The whole-body gallium scan accurately detected or excluded extrathoracic metastatic disease in 11 of 12 patients examined postmortem within three months of a gallium scan. An approach is recommended using gallium scanning along with chest roentgenograms for clinical staging and preoperative evaluation of patients with carcinoma of the lung. Specific organ scans should be reserved for the occasional symptomatic patient with a negative gallium scan or for clarification of an indeterminate gallium scan.     

Positron emission tomographic imaging with fluorodeoxyglucose isefficacious in evaluating malignant pulmonary disease

OBJECTIVE: Positron emission tomography (PET), when used with the intravenously administered radiopharmaceutical F-18 fluorodeoxyglucose (FDG), has the potential to help in the evaluation of patients with lung cancer because the radiopharmaceutical is concentrated by metabolically active cells. We conducted a retrospective study of PET-FDG in 96 patients evaluated at our institution over the past 2 years for suspected primary pulmonary neoplasms. PET-FDG results were compared with the findings of computed tomographic scans on the same patients. All patients underwent surgical exploration with or without resection of the malignant tumors. Sites of potential malignancy were subjected to biopsy and/or excision, with subsequent pathologic evaluation. RESULTS: A total of 96 patients with suspected or proven primary pulmonary malignant disease were evaluated. Sixty-six patients had histologically confirmed malignant tumors, and 30 had benign masses histologically. PET-FDG had an accuracy of detecting malignancy in pulmonary lesions of 92% (sensitivity 97%; specificity 89%). A total of 111 surgically sampled sites were from lymph nodes. PET-FDG was accurate in predicting the malignancy of nodes in 91% of instances, whereas computed tomography was correct in 64%. The sensitivity, specificity, and predictive accuracy of PET in detecting metastatic lymphadenopathy in mediastinal lymph nodes were 98%, 94%, and 95%, respectively. PET-FDG also changed the M stage in 8 (12%) patients (6 with and 2 without metastases). The 6 malignant (positive) lesions were correctly identified by PET-FDG, and the 2 without tumor were accurately predicted as benign (negative). CONCLUSION: These initial results suggest that PET-FDG is highly accurate in identifying and staging lung cancer. PET-FDG also appears to be more accurate in detecting metastatic mediastinal lymphadenopathy than computed tomographic scan.     

Mediastinal lymph node staging in suspected lung cancer: comparison of positron emission tomography with F-18-fluorodeoxyglucose and mediastinoscopy

BACKGROUND: In patients with bronchogenic carcinoma, mediastinal lymph node staging is essential for determining treatment options. In this retrospective analysis we compared the results of positron emission tomography (PET) using F-18 fluorodeoxyglucose with those of mediastinoscopy in nodal staging for suspected bronchogenic carcinoma. METHODS: From March 1997 to June 2001, 102 patients (86 male,16 female, age 62 +/- 9 years) underwent both PET and mediastinoscopy for radiologically suspected mediastinal lymph node disease in bronchogenic carcinoma. Total body emission scans were acquired 90 to 150 minutes after injection of 230 MBq of F-18 fluorodeoxyglucose. Mediastinoscopic evaluation of lymph node stations was performed according to the method of Mountain and Dresler (1R, 1L, 2L, 2R, 4L, 4R,7). Patients were eligible if surgical staging was performed within 6 weeks after the PET scan. RESULTS. Of the 102 patients, benign lesions were diagnosed in 15. In 87 patients malignant disease was proven by histology, and bronchogenic carcinoma was found in 82. Of 469 nodal stations analyzed, malignancy was documented by histology in 84. In PET analysis 79 true-positive and 304 true-negative samples were found. Five lymph node stations were false negative, and 81 samples were false positive. False-positive findings in PET frequently were seen in inflammatory lung disease. The sensitivity of PET was 94.1%, specificity was 79% with a diagnostic accuracy of 81.6%. The positive predictive value of PET was 49.3%, and the negative predictive value was 98.4%. CONCLUSIONS: In patients with positive PET scan results histologic verification appears necessary for exact lymph node staging. In view of the negative predictive value mediastinoscopy can be omitted in patients with bronchogenic carcinoma whose PET scan results were negative.     

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.     

Prolonged Survival After Extracranial Metastasectomy From Synchronous Resectable Lung Cancer

Background:Combined resection of solitary synchronous brain metastases and non–small-cell lung cancer has been shown to be successful. Thus, we proposed combining the surgery of solitary, extracranial metastases, and resectable lung cancer.Methods:Between March 1987 and December 1994, surgery was performed on nine patients with non–small-cell lung cancer with synchronous, solitary, extracranial, or distant metastasis: adrenal (n = 5), cutaneous (n = 2), axillary lymph node (n = 1) and kidney (n = 1). Criteria for operating on these patients included: primary tumor that was locally resectable in a radical manner, non–small-cell histology, no preoperative evidence of N2 disease, complete resection of histologically proven metastasis, and absence of other metastases found with computed tomography or bone scan.Results:Resection of the primary tumor and solitary metastases was achieved in all patients. Primary tumor was always resected by lobectomy. No mortality or major morbidity was reported. Five-year survival rate was 55.6%. Five patients who had adrenal (n = 3), or skin (n = 1), or axillary (n = 1) metastases, survived more than 5 years. All N2 patients (n = 2) died.Conclusions:The presence of solitary, distant metastasis should not be considered, per se, a factor for denying surgery for locally resectable, non–small-cell lung cancer. Unexpected, prolonged survival was demonstrated in our limited series.     

Can computed tomography of the chest stage lung cancer? Yes and no

To determine the accuracy of computed tomography (CT) of the chest in the staging of lung cancer, we studied 418 patients with primary pulmonary carcinoma between 1979 and 1986. Each had a preoperative scan performed before detailed operative staging. Each CT scan was analyzed for components of the current TNM staging system. Computed tomography sensitivity and specificity for mediastinal lymph node metastasis were 84.4% and 84.1%, with corresponding positive and negative predictive accuracies of 68.7% and 92.9%, respectively. When TNM stages were derived from CT scans, only 190 of 418 (45.4%) completely agreed with operative staging. An additional 53 of 418 (12.7%) predicted the correct stage, although components of the TNM system were incorrect. In 94 of 418 scans (22.5%) CT overestimated the stage, whereas in 81 (19.4%) CT downgraded the stage. Computed tomography suggested metastatic lesions in liver, lung, adrenal gland, bone, or abdominal lymph nodes in 40 of 373 scans (10.7%); only five of 40 (12.5%) had documented metastasis. In summary, CT of the chest cannot accurately stage primary lung carcinoma according to the TNM classification. Because the negative predictive accuracy for mediastinal lymph node metastasis remains high (92.9%), invasive staging can be deferred for definitive thoracotomy when no lymphadenopathy is evident on CT. The high negative predictive accuracy for scans of the chest and upper abdomen makes CT a useful tool for exclusion of metastatic disease.     

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.     

The impact of fluorodeoxyglucose F 18 positron-emission tomography on the surgical staging of non-small cell lung cancer

OBJECTIVES: Staging data on patients with non-small cell lung cancer were prospectively collected to evaluate the accuracy and anatomic information provided by fluorodeoxyglucose F 18 positron-emission tomography and its impact on improving the accuracy of surgical staging. METHODS: A total of 142 patients with potentially resectable non-small cell lung cancer were imaged with positron-emission tomography (neck to pelvis). Positron-emission tomographic scans were read prospectively with thoracic computed tomographic comparison. Patients without distant metastases at positron-emission tomography underwent staging with bronchoscopy and mediastinoscopy, with or without mediastinotomy or thoracoscopy. Patients with metastases, pleural implants, or N2 or N3 disease did not undergo primary resection. RESULTS: Positron-emission tomography revealed unsuspected distant metastases in 24 of 142 patients (16.9%) and unsuspected pleural implants in 6 others. Nodal stage was surgically established in 118 cases. Positron-emission tomography showed that 5 patients had nodal disease not accessible by mediastinoscopy. In 35 (24.6%) of these 142 cases, positron-emission tomography directed the evaluation away from routine bronchoscopy and mediastinoscopy staging that would have resulted in inappropriate treatment selection. Positron-emission tomography correctly differentiated resectable stages IA through IIIA (N1) from stages IIIA (N2) through IV in 88.7% of cases. In identifying N2 or N3 disease, positron-emission tomography had an accuracy of 90.7%, a sensitivity of 80.9%, a specificity of 96%, and positive and negative predictive values of 91.9% and 90.1%, respectively. Of the 8 cases in which positron-emission tomography missed N2 disease, 7 had the disease discovered by mediastinoscopy and 1 had it discovered at thoracotomy. CONCLUSIONS: The diagnostic accuracy of positron-emission tomography-enhanced clinical staging is high. Positron-emission tomography has previously been used primarily to screen for lymph node spread and distant metastases, but it also provides localizing information that allows directed and more sensitive surgical staging and refinement of patient selection for curative resection. Positron-emission tomography and surgical staging play complementary roles in the journey toward more accurate overall staging.     

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.     

Fluorodeoxyglucose positron emission tomography integrated with computed tomography to determine resectability of primary lung cancer

PURPOSE: Fluorodeoxyglucose positron emission tomography integrated with computed tomography (FDGPET/CT) was evaluated as a routine staging technique for primary lung cancer. MATERIALS AND METHODS: We prospectively compared FDG-PET/CT in determining clinical stage and surgical indication with conventional staging not including positron emission tomography (PET). A total of 50 consecutive patients diagnosed with primary lung cancer by cytological or histological examination were studied; 20 of them underwent surgery. RESULTS: Discrepancies between the two staging methods were observed in 14 patients (28%). The stage assigned by PET increased in 12 cases (24%) and decreased in 2 (4%). PET staging was accurate in eight cases with otherwise undetected distant metastases (M1) but was incorrect in six cases, including five where it overdiagnosed nodal metastases (N). Two clinical N3 patients (4%) would have missed a chance of surgery if the surgical indication had been determined by PET staging alone. According to our criteria for surgery, other patients were assigned correctly to surgery by PET staging. The maximum standard uptake value (maxSUV) of all primary lesions ranged from 0 to 23.0 (mean +/- SD, 8.0 +/- 4.4). The mean maxSUV among surgical cases (5.8 +/- 3.6) was significantly smaller than among nonsurgical cases (9.5 +/- 4.2) (P < 0.05). CONCLUSION: Staging examination including FDG-PET/CT and brain magnetic resonance imaging ordinarily can determine the clinical stage and resectability of primary lung cancer. False-positive findings in regional lymph nodes, possibly reflecting past infectious disease, are the most important remaining problem.     

Prospective Analysis of Accuracy of Positron Emission Tomography,Computed Tomography,and Endoscopic Ultrasonography in Staging of Adenocarcinoma of the Esophagus and the Esophagogastric Junction

Background: Exact preoperative staging of esophageal cancer is essential for accurate prognosis and selection of appropriate treatment modalities.Methods: Forty-two patients with adenocarcinoma of the esophagus or the esophagogastric junction suitable for radical esophageal resection were staged with positron emission tomography (PET), spiral computed tomography (CT), and endoscopic ultrasonography (EUS).Results: Diagnostic sensitivity for the primary tumor was 83% for PET and 67% for CT; for local peritumoral lymph node metastasis, it was 37% for PET and 89% for EUS; and for distant metastasis, it was 47% for PET and 33% for CT. Diagnostic specificity for local lymph node metastasis was 100% with PET and 54% with EUS, and for distant metastasis, it was 89% for PET and 96% for CT. Accuracy for locoregional lymph node metastasis was 63% for PET, 66% for CT, and 75% for EUS, and for distant metastasis, it was 74% with PET and 74% with CT. Of the 10 patients who were considered inoperable during surgery, PET identified 7 and CT 4. The false-negative diagnoses of stage IV disease in PET were peritoneal carcinomatosis in two patients, abdominal para-aortic cancer growth in one, metastatic lymph nodes by the celiac artery in four, and metastases in the pancreas in one. PET showed false-positive lymph nodes at the jugulum in three patients.Conclusions: The diagnostic value of PET in the staging of adenocarcinoma of the esophagus and the esophagogastric junction is limited because of low accuracy in staging of paratumoral and distant lymph nodes. PET does, however, seem to detect organ metastases better than CT.     

Role of CT assessment of mediastinal lymph nodes in the preoperative staging of T1 pulmonary carcinoma

The utility of the preoperative staging of T1 lung cancer is controversial. This is due to a lower prevalence of N2 metastases in tumors of small diameter. To assess the prevalence of N2 metastases in such tumors and the sensitivity and specificity of computed tomography in mediastinal sadiation, the authors reviewed CT scans and pathology reports of 56 patients who had undergone surgical resection of a T1 lung cancer so distributed: Adenocarcinoma 20 cases, adenosquamous carcinoma 14, Bronchioloalveolar carcinoma 7, Undifferentiated 7, Carcinoid 5, Small cells carcinoma 3. Mediastinal nodal metastases were present in 11 patients: 6 of them were correctly detected by CT scan. Some differences in terms of N2 prevalence and sensitivity were noted when the T1 were divided in two groups of diameter greater or smaller of 2 cm. Important considerations derived after dividing our patients according to the histological type. The prevalence of N2 metastases was greater in adenocarcinoma than in adenosquamous carcinoma but CT sensitivity was lower in adenocarcinoma (40% Vs 100%). The authors conclude that the prevalence of N2 metastases is high enough to request a preoperative sadiation, but the utility of CT in this purpose is limited by a low sensitivity.     

Oesophageal endoscopic ultrasound with fine needle aspiration improves and simplifies the staging of lung cancer

BACKGROUND: Positron emission tomography (PET) is accurate for mediastinal staging of lung cancer but has a moderate positive predictive value, necessitating pathological verification. Endoscopic ultrasonography with fine needle aspiration (EUS-FNA) is a technique for tissue verification of mediastinal and upper retroperitoneal abnormalities. The use of EUS-FNA may decrease the number of surgical procedures and thereby staging costs. METHODS: EUS-FNA was used prospectively for the cytological assessment of mediastinal and/or upper retroperitoneal PET hot spots in patients with suspected lung cancer. Only if EUS-FNA was positive for malignancy was subsequent mediastinoscopy or exploratory thoracotomy cancelled. The cost effectiveness of EUS-FNA was determined. RESULTS: Of 488 consecutive patients with suspected lung cancer, 81 were enrolled with mediastinal and/or upper retroperitoneal PET hot spots. EUS-FNA was positive in 50 (62%) patients, negative in six, and inconclusive in 25. Of the 31 negative or inconclusive patients, 26 underwent surgical staging (resulting in 14 patients with and 12 without mediastinal malignancy), while five patients had mediastinal metastases during follow up. No EUS-FNA related morbidity or mortality was encountered. The accuracy of the decision to proceed to surgery (or not) on the basis of EUS-FNA was 77% (95% CI 68 to 86). EUS-FNA detected more mediastinal abnormalities than PET except for the upper mediastinal region. Addition of EUS-FNA to conventional lung cancer staging reduced staging costs by 40% per patient, mainly due to a decrease in surgical staging procedures. CONCLUSION: EUS-FNA can replace more than half of the surgical staging procedures in lung cancer patients with mediastinal and/or upper retroperitoneal PET hot spots, thereby saving 40% of staging costs.     

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.     

Evaluation of lymph node metastases in squamous cell carcinoma of the esophagus with positron emission tomography

BACKGROUND: Previous studies suggest positron emission tomography (PET) may improve staging accuracy of esophageal cancer compared with conventional methods, especially in detecting occult distant metastases. We evaluated the accuracy of PET in the detection of lymph node metastasis prospectively with pathologic findings. METHODS: Fifty-three patients with squamous cell carcinoma underwent whole-body PET scan and chest computed tomography (CT). The findings of PET and chest CT of 50 patients who underwent curative esophagectomy with radical lymph node dissection were compared with the pathologic findings. RESULTS: Among 53 primary esophageal tumors, PET detected 51 (96.2%) and CT detected 49 (92.5%) tumors correctly. Nodal metastases were present in 108 of 436 dissected lymph node groups. PET detected 56 metastatic node groups (51.9% sensitivity, 94.2% specificity, 83.7% accuracy), compared with CT, which detected 16 (14.8% sensitivity, 96.7% specificity, 76.6% accuracy; sensitivity: p < 0.005). CONCLUSIONS: PET was more sensitive than CT in the detection of nodal metastases and may improve staging of squamous cell carcinoma of the esophagus.