Pulmonary metastatic melanoma -- the survival benefit associated with positron emission tomography scanning.

OBJECTIVE: Positron emission tomography (PET) scanning is more sensitive at detecting metastatic disease than conventional radiological techniques. For patients with pulmonary metastatic melanoma, we investigate if PET scanning to detect occult extra pulmonary disease prior to thoracotomy and metastectomy is associated with improved survival compared to patients staged by conventional radiology. METHODS: Between November 1984 and December 1999, 121 patients (90 males, 31 females) have undergone a thoracotomy and pulmonary metastectomy for metastatic melanoma. The age range was 19-84 years (mean 57, median 59). In every case all palpable nodules were removed and the diagnosis confirmed histologically. A total of 68 (56%) patients had a PET scan preoperatively, 53 (44%) underwent conventional or nuclear imaging. Patients with only radiologically isolated pulmonary disease are included. RESULTS: Survival is 100% complete and totals 238 pt/years (mean 2.2 years, median 1.4 years). Survival (+/-SE) at 1, 3, 5 and 7 years for all patients is 68% (+/-4.5) (n=67), 36.6% (+/-5.2) (n=27), 22.1% (+/-4.8) (n=15) and 13.5% (+/-4.2) (n=7), respectively. Survival (+/-SE) was significantly better at 3 and 5 years in patients who underwent a PET scan preoperatively (Log rank P=0.002). There was no significant difference in survival by 7 years. CONCLUSIONS: There is a significant survival benefit associated with excluding extra pulmonary disease using a PET scan prior to thoracotomy and metastectomy. We recommend that PET scanning be used in the investigation of patients with pulmonary metastatic melanoma prior to metastectomy.     

Preoperative positron emission tomography to evaluate potentially resectable hepatic colorectal metastases

HYPOTHESIS: Positron emission tomography (PET) influences clinical management in the preoperative evaluation of patients with hepatic metastases from colorectal cancer. DESIGN: Prospective cohort study. SETTING: Academic tertiary care center. PATIENTS: From January 1, 2000, through December 31, 2002, 71 consecutive patients referred with potentially resectable hepatic metastases based on conventional imaging findings underwent PET or PET with computed tomography in the subsequent preoperative evaluation. INTERVENTION: Performance of hepatic resection was based on the results of the overall preoperative evaluation. MAIN OUTCOME MEASURES: Concordance with conventional imaging findings, identification of additional findings, and change in clinical management were analyzed. RESULTS: The PET findings confirmed the lesions identified by conventional imaging techniques in 64 (90%) of the patients. Additional lesions were identified on PET in 23 patients (32%). The information obtained by PET resulted in a change in clinical management in 17 cases (24%). False-positive PET findings occurred in 6 patients (8%), whereas false understaging occurred in 11 (15%). In no cases did PET findings have an adverse impact on patient outcome. CONCLUSIONS: Positron emission tomography provides useful information in the selection of patients with hepatic metastases from colorectal cancer being considered for surgical therapy. Such improved selection may serve to reduce the number of unnecessary surgical explorations and result in improved long-term survival in patients undergoing resection. Positron emission tomography should be integrated into the routine preoperative evaluation of patients being considered for hepatic resection of colorectal metastases.     

Malignant prolactinoma with multiple intracranial metastases studied with positron emission tomography

A rare case of a patient with multiple intracranial metastases from a prolactin-secreting pituitary neoplasm is described. At the age of 14 years, the patient had been operated on for a sellar tumor; he presented 12 years later with severe headache, at which time computed tomographic and magnetic resonance imaging scans revealed multiple intracranial metastases. Histopathology examination showed pituitary neoplastic cells with positive immunostaining for prolactin. The patient was investigated with positron emission tomography (PET) and dopamine D2-receptor binding, and the amino acid metabolism of the tumor was characterized in vivo. High dopamine D2-receptor binding and high amino acid metabolism were found in the tumor. The patient was subsequently treated with bromocriptine injections that resulted in a decrease in serum prolactin levels, decreased dopamine D2-receptor binding, reduced amino acid metabolism, and a reduction in tumor volume. This case demonstrates a beneficial effect of bromocriptine treatment in a patient with prolactinoma with multiple intracranial metastases. It also illustrates the great potential of PET in the in vivo characterization of the D2-binding and the high sensitivity of 11C-labeled L-methionine in the follow-up of treatment in patients with pituitary adenomas.     

Fluorodeoxyglucose positron emission tomography for detection of recurrent or metastatic breast cancer

Fluorodeoxyglucose-positron emission tomography (FDG-PET) is a noninvasive imaging technique capable of identifying primary tumors and metastases with high sensitivity and accuracy. The aim of this study was to evaluate the diagnostic accuracy of whole-body FDG-PET imaging for the detection of recurrent or metastatic breast cancer after surgery. Whole-body FDG-PET imaging was performed on 27 patients with suspected recurrent breast carcinoma. PET images were evaluated qualitatively for each patient and lesion. FDG-PET scans showed that there were 61 reference sites of malignant or benign lesions in 27 patients. In a patient-based analysis, FDG-PET scans correctly identified 16 of 17 patients with recurrent or metastatic disease and 8 of 10 without recurrence, resulting in a sensitivity, specificity, and accuracy of 94%, 80%, and 89%, respectively. In a lesion-based analysis, FDG-PET scans correctly identified 46 of 48 lesion sites with recurrent or metastatic disease and 11 of 13 without recurrence. The overall sensitivity, specificity, and accuracy for all lesion sites were 96%, 85%, and 93%, respectively. FDG-PET scans revealed unsuspected recurrent or metastatic diseases in 8 of 27 (30%) of patients and 11 of 20 (55%) distant metastatic lesions. In 13 patients treatment was altered by the outcome of the PET scan. We concluded that whole-body FDG-PET scan is a useful diagnostic imaging modality for detecting recurrent or metastatic breast carcinoma in patients suspected of having recurrent disease after primary surgery.     

正电子发射型断层显像在结直肠癌肝转移诊断中的应用

目的 评价正电子发射型断层显像(PET)在结直肠癌术后肝转移诊断中的作用。方法 对18例怀疑结直肠癌术后肝转移的患者和3例怀疑其他疾病的患者进行PET检查，通过与CT比较及手术探查，评价PET在结直肠癌肝转移诊断中的作用。结果 怀疑术后肝转移的18例患者，经PET显像确诊17例，其中14例同时伴有肝脏以外的其他脏器转移(肺转移2例、腹壁转移2例、骨转移1例、腹腔淋巴结转移6例、纵隔淋巴结转移2例、锁骨上淋巴结转移1例)；PET诊断阴性的1例患者，随访1年后仍无瘤存活。3例怀疑其他疾病的患者经PET检查发现有结肠癌伴肝转移。结论 与CT相比，PET对结直肠癌术后肝脏及其他部位转移的敏感度更高，对术后肝转移患者是否选择再次手术具有更好的指导意义。     

The role of positron emission tomography (PET) in the detection of local recurrence and metastases of colorectal cancer

We presented here the results of PET imaging of 12 patients, previously operated on for colorectal cancer and followed at the 1st Department of Surgery, University of Debrecen. The tests were carried out using 0.15 mCi/kg FDG injections. Whole body imaging was performed in eleven patients. The indication for PET was elevated tumor marker levels in three patients, although CT scan was negative. The PET scan showed lymph node, hepatic and disseminated lymph node metastases with liver involvement in these patients. Suspicious lesions were found on CT scan in the pelvis of four patients. Local recurrence was identified in three of them, PET was negative in the fourth case. Bone scan suggested rib metastasis in one patient, which was not supported at PET investigation. In one patient, the malignant nature of large retroperitoneal lymph nodes could not be determined by CT. PET imaging proved that they were malignant and detected a previously unknown pulmonary metastasis at the same time. In one patient both pulmonary and liver metastases were seen on CT, whereas PET confirmed only the latter. Similarly, CT failed to identify liver metastasis detected at ultrasound, while PET proved it. Finally, a pulmonary metastasis detected on X-ray, could be confirmed by PET only. Based on our experience, we recommend PET-scanning with FDG when conventional imaging is equivocal and/or elevated tumor marker levels are present during follow-up. FDG-PET is important in the detection of local recurrence and metastases as well. It is advisable to use PET more often in the evaluation of patients with recurrent colorectal cancer in order to diagnose recurrences in earlier stages, which helps to identify patients who will benefit from surgery.     

Positron emission tomography for detection of lymph node metastases in lung cancer

Although radiography, computed tomography (CT), and magnetic resonance imaging are still the methods of choice for the study of lung cancer, they have certain limitations in the evaluation of mediastinal lymph node metastases. Positron emission tomography (PET) with 18F-fluoro-2-deoxy-D-glucose (FDG) has recently emerged as a practical and useful imaging modality in patients with lung cancer. We evaluated the usefulness of FDG-PET in the detection of mediastinal lymph node metastases and then compared the findings with the results of CT by region based on the histological diagnosis. For FDG-PET, the sensitivity, specificity and accuracy were 93%, 76%, and 98%, respectively, whereas, for CT, this was 65%, 87%, and 82%, which showed significant differences. FDG-PET is significantly more accurate than CT in lymph node staging of lung cancer, and also can improve the diagnostic accuracy in distant metastases.     

Positron emission tomography is superior to computed tomography for metastatic detection in melanoma patients

BACKGROUND: Whole-body positron emission tomography (PET) provides diagnostic information not currently available with traditional imaging and may improve the accuracy of staging melanoma patients. METHODS: A retrospective cohort review was performed of 104 patients with primary or recurrent melanoma who underwent PET to determine sensitivity/specificity for metastatic detection compared with body computed tomography (CT). One hundred fifty-seven PET and 70 CT scans were analyzed, with a median patient follow-up of 24 months. Metastases were confirmed with positive histology (87.5%) or documented disease progression (12.5%). Fifty-three patients prospectively underwent consecutive studies within a mean 3-week interval for direct comparative analysis. RESULTS: PET demonstrated 84% sensitivity (95% confidence interval [CI],.78 to.89) and 97% specificity (95% CI,.91 to.99), whereas CT showed 58% sensitivity (95% CI,.49 to.66) and 70% specificity (95% CI,.51 to.84). Exclusion of areas not evaluated on CT (head, neck/supraclavicular, extremities) increased CT sensitivity to 69% (95% CI,.59 to.77). Sixty-six consecutive PET and CT scans were performed with 81% and 57% of metastases detected, respectively. CONCLUSIONS: PET is more sensitive and specific than CT for detection of melanoma metastasis and should be considered the primary staging study for recurrent disease. PET shows greater ability to detect soft tissue, small-bowel, and lymph node metastasis that do not meet criteria designated as abnormal by CT. PET is superior to CT even when sites not routinely evaluated by CT are excluded from comparative analysis.     

Fluorine-18-fluorodeoxyglucose positron emission tomography is useless for the detection of local recurrence after radical prostatectomy.

OBJECTIVE: After radical retropubic prostatectomy a rise of the prostate-specific antigen (PSA) indicates a local recurrent or metastatic disease. If the bone scan shows no apparent bone metastasis, morphological imaging methods like x-ray computed tomography, magnetic resonance imaging or transrectal ultrasound often cannot distinguish between postoperative scar and local recurrence. Therefore we investigated the feasibility of fluorine-18-fluorodeoxyglucose positron emission tomography (F-18 FDG PET) for metabolic characterization of prostatic cancer, especially for differentiation of scar or recurrent prostate cancer after radical prostatectomy. METHODS: Dynamic PET with 370 MBq F-18 deoxyglucose (F-18 FDG) up to 60 min p.i. was performed in 2 patients with biopsy-proven benign prostatic hyperplasia, in 11 patients with a histologically proven prostate cancer prior to radical retropubic prostatectomy (RRP) and 7 patients with suspected local recurrence (with negative bone scan) after RRP prior to biopsy of anastomosis (3 local recurrence, 4 postoperative scar). RESULTS: Prostate cancer showed a very low F-18 FDG uptake. The placement of regions of interest was only possible by the use of other imaging methods. There was not difference between the F-18 FDG uptake of benign prostate hyperplasia, prostate carcinoma, postoperative scar or local recurrence after radical prostatectomy. CONCLUSION: F-18 FDG seems not to be useful to distinguish between postoperative scar and local recurrence after radical prostatectomy.     

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.     

Role for positron emission tomography in skeletal diseases

Imaging plays a prominent role in the diagnosis and management of rheumatic diseases. Conventional imaging methods provide high-resolution structural information but usually fail to distinguish between active lesions and residual changes. Positron emission tomography (PET) with the tracer 18F-fluorodeoxyglucose (18F-FDG) was recently introduced into clinical practice as a means of obtaining information on both structure and metabolic activity. 18F-FDG-PET is widely used in oncology and may be valuable in patients with infections or inflammatory diseases, most notably vasculitis. Although encouraging results have been published, the number of studies remains small, as 18F-FDG-PET is an expensive investigation that is not available everywhere. Further work is needed to determine the cost-effectiveness ratio of 18F-FDG-PET in patients with infections or inflammatory diseases. Imaging plays a prominent role in the diagnosis and management of many musculoskeletal diseases. Although considerable progress has been made recently, the structural information supplied by conventional imaging methods is inadequate in some patients. Positron emission tomography (PET) after injection of 18fluorodeoxyglucose (18F-FDG) provides information on tissue metabolism. The usefulness of 18F-FDG-PET in oncology is now widely recognized. Other uses are emerging, in part thanks to the development of new cameras that combine dedicated detectors and an X-scanner in order to ensure accurate three-dimensional localization of metabolically active lesions. However, the exact role for 18F-FDG-PET needs to be studied in larger populations of patients.     

Language localization with activation positron emission tomography scanning.

We report the first instance of the use of 3-dimensional magnetic resonance imaging anatomically correlated to positron emission tomography (PET) scanning to identify language areas in a patient with an arteriovenous malformation (AVM) in the posterior speech region. The patient was a 24-year-old right-handed woman with an angiographically proven AVM (3-4 cm) in the left mid-posterior second temporal convolution in whom a left intracarotid injection of sodium Amytal produced significant language disruption. A baseline PET cerebral blood flow study identified the AVM, and an activation PET scan performed during the reading and speaking of simple words showed increased activity in the left parastriate cortex (the second visual area), in the left posterior third frontal convolution (Broca's area), and in the left inferior and midtemporal gyri (Wernicke's area). Increased activity was also noted in the right and left transverse temporal (Heschl's) gyri, in the left precentral gyrus, in the left medial superior frontal gyrus (the supplementary motor area), and in the right cerebellum. We conclude that activation PET scanning is useful in the preoperative assessment of patients who harbor cerebral AVMs in classically described speech regions.     

Clinical use of fluorodeoxyglucose F 18 positron emission tomography for detection of renal cell carcinoma

PURPOSE: We evaluate the role of fluorodeoxyglucose F 18 positron emission tomography (PET) in patients with renal cell carcinoma (RCC) by retrospective review. To our knowledge this series is the largest reviewing the use of PET in patients with RCC. MATERIALS AND METHODS: A total of 66 patients who underwent 90 PET scans for suspected or known RCC were identified. Dictated reports of PET, chest computerized tomography (CT), abdominal/pelvic CT and bone scan were examined with confirmation of results by histopathology or followup of at least 1 year. The accuracies of PET and conventional imaging modalities were compared. RESULTS: PET exhibited a sensitivity of 60% and specificity of 100% for primary RCC tumors (abdominal CT demonstrated 91.7% sensitivity and 100% specificity). For retroperitoneal lymph node metastases and/or renal bed recurrence, PET was 75.0% sensitive and 100.0% specific (92.6% sensitivity and 98.1% specificity for abdominal CT). PET had a sensitivity of 75.0% and a specificity of 97.1% for metastases to the lung parenchyma compared to 91.1% and 73.1%, respectively, for chest CT. PET had a sensitivity of 77.3% and specificity of 100.0% for bone metastases, compared to 93.8% and 87.2% for combined CT and bone scan. In 39 scans (32 patients) PET failed to detect RCC lesions identified by conventional imaging. CONCLUSIONS: The role of fluorodeoxyglucose F 18 PET in the detection of RCC is limited by low sensitivity. With superior specificity PET may have a complementary role as a problem solving tool in cases that are equivocal on conventional imaging.     

Utility of 18F-FDG positron emission tomography scanning on selection of patients for resection of hepatic colorectal metastases

BACKGROUND: Hepatectomy represents a standard and potentially curative therapy for hepatic colorectal metastases. However, up to two thirds of patients explored for resection are found to have unsuspected disease, which precludes resection. METHODS: In order to determine if 18F-FDG positron emission tomography (PET) scanning may prevent unnecessary surgery, a group of 40 patients being considered for hepatic resection but at high risk for unresectable disease by clinical criteria were subjected to whole body 18F-FDG-PET scanning. Effect on clinical outcome was evaluated. In addition, PET findings in the 25 patients who underwent resection of hepatic metastases were directly compared with the resected specimen to determine the sensitivity of 18F-FDG PET scanning in the liver. RESULTS: Findings on 18F-FDG-PET scanning influenced the clinical management in 16 patients (40%) and directly altered management in 9 cases (23%). Six patients were spared laparotomy, and 3 others had PET-directed surgery that found extrahepatic tumor and spared the patient unwarranted liver resection. In 3 cases PET missed peritoneal metastases found on laparotomy. In these cases all missed tumors were less than 1 cm in size. Out of 52 resected hepatic lesions, 18F-FDG-PET detected 37. Within the liver, sensitivity of detection was also related to size. Only 25% of hepatic lesions smaller than 1 cm were detected by PET, while 85% of lesions larger than 1 cm were detected. CONCLUSIONS: FDG-PET is best for detecting extrahepatic disease. There are few false positives, and surgeons should carefully evaluate and biopsy extrahepatic positive sites. This test should be used for patients at high risk for extrahepatic disease and should be evaluated prospectively for all patients under consideration for liver resection.