Combined contrast-enhanced computed tomography and 18-fluoro-2-deoxy-D-glucose-positron emission tomography in the diagnosis and staging of non-small cell lung cancer

We present the current optimal uses and limitations of positron emission tomography/computed tomography (PET/CT) as it relates to the diagnosis and staging of non-small cell lung cancer (NSCLC). PET/CT demonstrates increased accuracy in the workup of solitary pulmonary nodules for malignancy compared with CT alone, and we discuss its benefits and limitations. We review pitfalls in measured standardized uptake values of lung lesions caused by respiratory artifacts, the lower sensitivity for detection of small lung nodules on non-breath-hold CT, and the benefits of obtaining an additional diagnostic CT for the maximum sensitivity of lung nodule detection. There are limitations of quantitatively comparing separate PET/CT examinations from different facilities with standardized uptake values. As for staging, we describe how PET/CT supplements clinical tumor-nodes-metastases (ie, TNM) staging, as well as mediastinoscopy, endobronchial ultrasound, and endoscopic ultrasound, which are the gold standard pathologic staging methods. We touch on the 7th edition TNM staging system based on the work by the International Association for the Study of Lung Cancer, an anatomically based staging method.     

Axillary staging using positron emission tomography in breast cancer patients qualifying for sentinel lymph node biopsy

Axillary lymph node dissection (ALND) is the standard of care for nodal staging of patients with invasive breast cancer. Due to significant somatic and psychological side effects, replacement of ALND with less invasive techniques is desirable. The goal of this study was to evaluate the clinical usefulness of axillary lymph node (ALN) staging by means of positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) in breast cancer patients qualifying for sentinel lymph node biopsy (SLNB). FDG-PET was performed within 1 week before surgery in 24 clinically node-negative breast cancer patients with tumors smaller than 3 cm. Sentinel lymph nodes (SLNs) were identified by preoperative lymphoscintigraphy following peritumoral technetium 99m-labeled colloid albumin injection, and by intraoperative gamma detector and blue dye localization. Following SLNB, a standard ALND was performed. Serial sectioning and immunohistochemistry of the SLN as well as standard histologic examination of the non-SLN was performed. FDG-PET detected all primary breast cancers. Staging of ALNs by PET was accurate in 15 of 24 patients (62.5%), whereas PET staging was false negative in 8 of 10 node-positive patients and false-positive in 1 patient. The sensitivity, specificity, positive predictive value, and negative predictive value of FDG-PET for nodal status was 20%, 93%, 67%, and 62%, respectively. The mean diameter of false-negative ALN metastases was 7.5 mm (range 1-15 mm). Lymph node staging using FDG-PET is not accurate enough in clinically node-negative patients with breast cancer qualifying for SLNB and should not be used for this purpose.     

Application of whole-body positron emission tomography in the imaging of esophageal cancer: Report of a case

We describe herein a case of esophageal cancer in which both primary and metastatic lymph node foci were successfully imaged with whole-body positron emission tomography (PET) scanning. A 75-year-old woman with biopsy-proven squamous cell carcinoma of the esophagus underwent whole-body PET scanning for staging evaluation. The patient was injected with 373.7 MBq [¹⁸F]-2-fluoro-2-d-deoxyglucose (FDG), and 60 min later, scanning was performed from the neck to the pelvis. The whole-body images showed intense FDG uptake in the primary lesion and multiple focal areas of increased FDG uptake in the mediastinum and abdomen, which corresponded to the lymph node foci confirmed by computed tomography (CT) scan. To our knowledge, this is the first report of whole-body PET scanning being applied in the imaging of esophageal cancer.     

The decision to operate: role of integrated computed tomography positron emission tomography in staging oesophageal and oesophagogastric junction cancer by the multidisciplinary team

OBJECTIVE: Our objective was to assess the role of fusion positron emission tomography-computed tomography (PET-CT) in staging patients for minimally invasive oesophagectomy (MIO) with potentially resectable disease from the perspective of a multidisciplinary team (MDT) deciding on operability with conventional staging investigations. METHODS: Fifty consecutive patients presenting with potentially operable oesophageal or oesophagogastric junctional tumours were staged with computed tomography (CT) and endoluminal ultrasound (EUS). The MDT categorised patients as group A (n=33; CT N0M0) or group B (n=17; CT N1/possible M1). All patients underwent FDG PET-CT. Patients with localised disease (at T3), including single level N1 disease on PET-CT, were deemed suitable for induction chemotherapy followed by surgery. RESULTS: PET-CT re-categorised 12% of patients as inoperable on grounds of distant metastases (four in group A, two in group B). Five patients did not proceed to resection for other reasons. Two had metastatic disease at thoracoscopy. Resection specimens (n=37) contained 24 nodes (median). Compared with pN status, positive predictive value of PET-CT was 40% and negative predictive value was 43%. The expected PET-CT N1 group had the highest mean number of involved nodes. Median survival for all patients (n=50) was 31.9 months for group A compared with 17.3 months for group B (not statistically significant). There was no significant difference between patients who were PET-CT N0 or N1 in survival or disease-free survival in patients undergoing surgery (n=37). CONCLUSIONS: PET-CT informs the MDT decision to operate in avoiding futile surgery in stage IV disease or widespread nodal disease. In this study, overall PET-CT N1 status has low positive and negative predictive value for overall pN status.     

Positron‐emission tomography/computed tomography (PET/CT) in the initial staging of primary rectal cancer

Objective The aim of this study was to assess the role of ¹⁸flourodeoxyglucose positron‐emission tomography/computed tomography (PET/CT) in the initial staging of primary rectal adenocarcinoma. Method A total of 20 patients with adenocarcinoma of the rectum were assessed with both PET/CT and conventional staging (CT chest/abdomen/pelvis, MRI rectum). Discordance with conventional imaging and incidental findings on PET were recorded and the patients presented to a colorectal cancer multidisciplinary team to assess management changes. Patients were followed up so that discordant or incidental findings could be verified by intra‐operative examination, imaging or histology where possible. Results Positron‐emission tomography/computed tomography correctly identified the primary tumour in all 20 patients. Comparing PET/CT with conventional staging modalities, there were 11 discordant or incidental findings in nine patients (45%). This resulted in a potential change in stage in 30% (four patients downstaged and two upstaged). PET/CT suggested additional neoplastic pathology in three patients and excluded the same in two patients. The incidental neoplastic findings were of minor clinical significance and one was eventually deemed false positive. While PET/CT resulted in potential management changes in five patients (25%), no changes in surgical management occurred. When tumours were grouped according to conventional stage, PET/CT resulted in fewer changes in stage in stage I (0%), compared with stages II to IV (43%) (P = 0.08). Conclusion Positron‐emission tomography/computed tomography provides additional information to conventional staging in primary rectal cancer. This information produced minor management changes in this study and did not effect surgical management. PET/CT may be most appropriately used selectively in more advanced stages and where indeterminate findings exist with conventional staging.     

Clinical value of whole body fluorine‐18 fluorodeoxyglucose positron emission tomography/computed tomography in the detection of metastatic bladder cancer

Objectives: To investigate the value of whole‐body fluorine‐18 2‐fluoro‐2‐deoxy‐D‐glucose positron emission tomography/computed tomography for the detection of metastatic bladder cancer. Methods: From December 2006 to August 2010, 60 bladder cancer patients (median age 60.5 years old, range 32–96) underwent whole body positron emission tomography/computed tomography positron emission tomography/computed tomography. The diagnostic accuracy was assessed by performing both organ‐based and patient‐based analyses. Identified lesions were further studied by biopsy or clinically followed for at least 6 months. Results: One hundred and thirty‐four suspicious lesions were identified. Among them, 4 primary cancers (2 pancreatic cancers, 1 colonic and 1 nasopharyngeal cancer) were incidentally detected, and the patients could be treated on time. For the remaining 130 lesions, positron emission tomography/computed tomography detected 118 true positive lesions (sensitivity = 95.9%). On the patient‐based analysis, the overall sensitivity and specificity resulted to be 87.1% and 89.7%, respectively. There was no difference of sensitivity and specificity in patients with or without adjuvant treatment in terms of detection of metastatic sites by positron emission tomography/computed tomography. Compared with conventional imaging modality, positron emission tomography/computed tomography correctly changed the management in 15 patients (25.0%). Conclusions: Positron emission tomography/computed tomography has excellent sensitivity and specificity in the detection of metastatic bladder cancer and it provides additional diagnostic information compared to standard imaging techniques.     

Accuracy of computed tomography in nodal staging of colon cancer patients

AIM: To predict node-positive disease in colon cancer using computed tomography(CT).METHODS: American Joint Committee on Cancer stage Ⅰ-Ⅲ colon cancer patients who underwent curavtiveintent colectomy between 2007-2010 were identified at a single comprehensive cancer center. All patients had preoperative CT scans with original radiology reports from referring institutions. CT images underwent blinded secondary review by a surgeon and a dedicated abdominal radiologist at our institution to identify pericolonic lymph nodes(LNs). Comparison of outside CT reports to our independent imaging review was performed in order to highlight differences in detection in actual clinical practice. CT reviews were compared with final pathology. Results of the outside radiologist review, secondary radiologist review, and surgeon review were compared with the final pathologic exam to determine sensitivity, specificity, positive and negative predictive values, false positive and negative rates, and accuracy of each review. Exclusion criteria included evidenceof metastatic disease on CT, rectal or appendiceal involvement, or absence of accompanying imaging from referring institutions.RESULTS: From 2007 to 2010, 64 stageⅠ-Ⅲ colon cancer patients met the eligibility criteria of our study. The mean age of the cohort was 68 years, and 26(41%) patients were male and 38(59%) patients were female. On final pathology, 26 of 64(40.6%) patients had nodepositive(LN+) disease and 38 of 64(59.4%) patients had node-negative(LN-) disease. Outside radiologic review demonstrated sensitivity of 54%(14 of 26 patients) and specificity of 66%(25 of 38 patients) in predicting LN+ disease, whereas secondary radiologist review demonstrated 88%(23 of 26) sensitivity and 58%(22 of 38) specificity. On surgeon review, sensitivity was 69%(18 of 26) with 66% specificity(25 of 38). Secondary radiology review demonstrated the highest accuracy(70%) and the lowest false negative rate(12%), compared to the surgeon review at 67% accuracy and 31% false negative rate and the outside radiology review at 61% accuracy and 46% false negative rate.CONCLUSION: CT LN staging of colon cancer has moderate accuracy, with administration of NCT based on CT potentially resulting in overtreatment. Active search for LN+ may improve sensitivity at the cost of specificity.     

Preoperative intrathoracic lymph node staging in patients with non-small-cell lung cancer: accuracy of integrated positron emission tomography and computed tomography

Objective: To evaluate the accuracy of integrated positron emission tomography with ¹⁸F-fluoro-2-deoxy-d-glucose (FDG) and computed tomography (PET/CT) in preoperative intrathoracic lymph node staging in patients with non-small-cell lung cancer (NSCLC) and to ascertain the role of invasive staging in verifying positron emission tomography (PET)/computed tomography (CT) results. Methods: Retrospective, single institution study of consecutive patients with suspected or pathologically proven, potentially resectable NSCLC undergoing integrated PET/CT scanning in the same PET centre. Lymph node staging was pathologically confirmed on tissue specimens obtained at mediastinoscopy and/or thoracotomy. Statistical evaluation of PET/CT results was performed on a per-patient and per-nodal-station bases. Results: A total of 1001 nodal stations (723 mediastinal, 148 hilar and 130 intrapulmonary) were evaluated in 159 patients. Nodes were positive for malignancy in 48 (30.2%) out of 159 patients (N1 = 17; N2 = 30; N3 = 1) and 71 (7.1%) out of 1001 nodal stations (N1 = 24; N2 = 46; N3 = 1). At univariate analysis, lymph node involvement was significantly associated (p < 0.05) with the following primary tumour characteristics: increasing diameter, maximum standardised uptake value >9, central location and presence of vascular invasion. PET/CT staged the disease correctly in 128 out of 159 patients (80.5%), overstaging occurred in nine patients (5.7%) and understaging in 22 patients (13.8%). The overall sensitivity, specificity, positive and negative predictive values, and accuracy of PET/CT for detecting metastatic lymph nodes were 54.2%, 91.9%, 74.3%, 82.3% and 80.5% on a per-patient basis, and 57.7%, 98.5%, 74.5%, 96.8% and 95.6% on per-nodal-station basis. With regard to N2/N3 disease, PET/CT accuracy was 84.9% and 95.3% on a per-patient basis and on per-nodal-station basis, respectively. Referring to nodal size, PET/CT sensitivity to detect malignant involvement was 32.4% (12/37) in nodes <10 mm, and 85.3% (29/34) in nodes ≥10 mm. Conclusion: Our data show that integrated PET/CT provides high specificity but low sensitivity and accuracy in intrathoracic nodal staging of NSCLC patients and underscore the continued need for surgical staging.     

The role of positron emission tomography in the management of colorectal cancer

Positron emission tomography (PET) is a functional imaging modality that has made the transition from the research enviroment to the clinical enviroment over the last 10 years. Its major role is in the field of oncology where it is being used increasingly in the management of several tumour types including colorectal cancer. This review aims to outline the current and future role of PET scanning in the field of colorectal cancer.