Positron emission tomography in the staging and management of breast cancer

BACKGROUND: Breast cancer is the commonest cause of cancer death in women in the Western world, and imaging is essential in its diagnosis and staging. Metabolic imaging is a novel approach to improving the detection of cancers, as malignant transformation of cells is often associated with increased metabolic activity. This review assesses the possible role of positron emission tomography (PET) as a single non-invasive imaging modality to replace or complement current imaging and surgical practices in the diagnosis and staging of breast cancer. METHODS AND RESULTS: A Medline search was performed and articles were cross-referenced with other relevant material. Evaluation of primary breast cancer with PET has shown a sensitivity of between 64 and 100 per cent and a specificity of 33-100 per cent; diagnostic accuracy appears to be related to tumour size. Difficulties arise in altered fluorodeoxyglucose uptake in lobular carcinoma, carcinoma in situ and benign inflammatory breast disease. In axillary staging, sensitivities of between 25 and 100 per cent have been reported, but with a false-negative of up to 20 per cent. In the assessment of distant metastasis and asymptomatic patients with raised levels of tumour markers, PET was superior to conventional imaging modalities. CONCLUSION: PET is not a single diagnostic and staging tool that can replace current surgical, histological and radiological staging. Its main role in breast cancer lies in the investigation of metastatic disease and the evaluation of pathological response to various chemotherapeutic regimens.     

Positron emission tomography with F-18-fluorodeoxyglucose in a combined staging strategy of esophageal cancer prevents unnecessary surgical explorations

Distant metastases or local invasion are frequently found during the explorative phase of surgery for esophageal cancer. This study was performed to determine the rate of patients with incurable disease encountered during exploration and to examine the impact of preoperative staging, including positron emission tomography (PET), on the number of unnecessary explorations. The records of 203 patients with esophageal cancer who were eligible for curative resection were retrospectively reviewed. The surgical reports were analyzed to obtain the reasons for abandoning resection. Furthermore, the different staging modalities according to the related time interval were reviewed for each patient to analyze the influence of them on the number of explorations. After exploratory surgery, resection was abandoned in 78 of the 203 patients (38%) because of distant metastases (n = 59; 29%), metastatic spread and local irresectability (n = 5; 2%), and local irresectability (n = 14; 7%). In a logistic regression model with all preoperative staging modalities and the year of examination as independent variables, F-18-fluorodeoxyglucose (FDG)-PET) was the only modality that predicts intended curative resection in these patients (P < 0.001). In patients with esophageal cancer who are suitable for potentially curative surgery, resection was abandoned mainly because of distant metastases encountered during exploration. The addition of FDG-PET may have reduced the rate of unnecessary surgery in this group of patients. Presented at the Forty-Fifth Annual Meeting of The Society for Surgery of the Alimentary Tract, New Orleans, Louisiana, May 15–19, 2004 (poster presentation).     

Positron emission tomography in lung cancer

Recent advances in positron emission tomography (PET) with 2-deoxy-2-fluoro [F-18]-d-glucose (FDG) has enabled not only the diagnosis and staging of lung cancer but also the prediction of its malignancy grade. However, FDG-PET has been known to have several pitfalls for imaging of lung cancer. For the effective clinical use of FDG-PET in lung cancer, we reviewed the pitfalls of using FDG-PET in the diagnosis of pulmonary nodules, semiquantitative analysis of FDG-uptake, N-staging, prediction of tumor aggressiveness, prognostic significance, and prediction of pathological response after chemoradiotherapy. __________ This review was submitted at the invitation of the editorial committee.     

Positron emission tomography does not add to computed tomography for the diagnosis and staging of pancreatic cancer

BACKGROUND: Positron emission tomography (PET) has been proposed for pancreatic cancer diagnosis and staging. METHODS: 112 patients with suspected pancreatic cancer underwent 18F-fluoro-2-deoxy-D-glucose gamma camera PET and computed tomography (CT), of whom 62 also had laparoscopic ultrasonography and 70 underwent abdominal exploration for potential resection. The final diagnosis was malignancy in 78 and benign disease in 34 patients (25 with chronic pancreatitis). RESULTS: The diagnostic sensitivity and specificity for PET were 73 and 60% compared to 89 and 65% for CT respectively (Cohen's kappa = 0.59). In 30 patients CT was equivocal with cancer in 14 and benign disease in 16. PET correctly diagnosed 13 of these patients (cancer in 6 and benign disease in 7), interpreted 4 as equivocal (cancer in 3 and benign disease in 1) but was incorrect in the remaining 13 patients (cancer in 5 and benign disease in 8). The sensitivity and specificity for detecting small volume metastatic disease were 20 and 94% for CT and 22 and 91% for PET, respectively. CONCLUSION: PET had a similar accuracy to that of CT for imaging pancreatic cancer but it did not provide any additional information in patients with equivocal CT findings and currently would seem of little benefit for the staging of pancreatic cancer.     

Positron emission tomography and colorectal cancer

BACKGROUND: The oncological applications of positron emission tomography (PET) have gained widespread acceptance. This rapidly evolving technology has been applied successfully to colorectal cancer, but has not yet become part of routine clinical practice. This review considers (1) the biological basis for the use of PET in colorectal cancer, (2) the technical aspects of PET relevant to the referring clinician and (3) the application of PET to the management of primary and recurrent disease. METHODS: A Medline database search was performed for the period 1980-2000. Experience was also drawn from the first 40 patients with colorectal cancer investigated at this institution. RESULTS AND CONCLUSION: PET has a proven role, and is cost effective in the management of recurrent cancer and the monitoring of therapy. However, further evaluation is still required to justify its routine use for other indications in colorectal cancer. Development of new positron-labelled radio- pharmaceuticals, in parallel with advances in detector technology and innovative models for tracer production and distribution, means that the availability of PET and its applications in the management of colorectal cancer will expand over the coming years.     

Positron emission tomography for staging and management of malignant melanoma

BACKGROUND: The incidence of malignant melanoma is rising; it now has an incidence of ten per 100 000 per annum in the UK. The development of metastases is unpredictable, but prognosis is linked directly to the initial stage at diagnosis. Positron emission tomography (PET) can allow the detection of malignant cells at a relatively early stage. METHODS: A review of the literature was undertaken by searching the Medline database for the period 1980-2000 without any language restrictions. RESULTS: The overall sensitivity and specificity of PET are 74-100 and 67-100 per cent respectively. PET has a reduced sensitivity and specificity for thinner lesions (less than 1 x 5 mm). Comparison with computed tomography and magnetic resonance imaging has shown a higher sensitivity and specificity for PET in all regions of the body except the thorax. CONCLUSION: Currently the accepted indication for PET is recurrent melanoma when surgical intervention is being considered. However, other potential indications include the detection of occult or distant metastasis at initial presentation and the clarification of abnormal radiological findings at follow-up. The routine use of PET for American Joint Commission on Cancer stage I or II disease is of uncertain benefit and is not indicated at present.     

Positron emission tomography in non-medullary thyroid cancer

While iodine scanning is the mainstay of functional imaging in differentiated thyroid cancer, there is now a significant body of literature regarding positron emission tomography with 2-fluoro-2-deoxy glucose in thyroid cancer. This clinical review will examine the evidence supporting the use of 2-fluoro-2-deoxy glucose-positron emission tomography throughout the diagnosis and management of thyroid cancer, and provide suggestions for its clinical use and potential future roles.     

Positron emission tomography (PET) and combined imaging modalities for staging lung cancer

FDG PET in its current form supplements but does not yet replace other noninvasive imaging modalities for the evaluation and staging of the patient with NSCLC. Clinicians await further data from well-designed clinical trials to help integrate FDG PET into current clinical practice. Looking forward, sophisticated radiolabeling techniques promise to improve both the diagnostic accuracy of PET and our ability to deliver targeted cancer therapy to patients.     

Positron emission tomography

Summary One of the most exciting new techniques introduced in the last ten years is positron emission tomography (PET). PET provides quantitative, three-dimensional images for the study of specific biochemical and physiological processes in the human body. This approach is analogous to quantitativein vivo autoradiography but has the added advantage of permitting non-invasivein vivo studies. PET scanning requires a small cyclotron to produce short-lived positron emitting isotopes such as oxygen-15, carbon-11, nitrogen-13 and fluorine-18.Proper radiochemical facilities and advanced computer equipment are also needed. Most important, PET requires a multidisciplinary scientific team of physicists, radiochemists, mathematicians, biochemists and physicians. This review analyses the most recent trends in imaging technology, radiochemistry, methodology, and clinical applications of positron emission tomography.Reproduced with kind permission of Pergamon Press from the special issue of Radiation Physics and Chemistry on Radiation and Medicine (1984). Guest Editors: B. C. Lentle and H. Singh.     

The utility of positron emission tomography for the diagnosis and staging of recurrent esophageal cancer

OBJECTIVE: To study the utility of whole-body positron emission tomography with (18)F-fluoro-deoxy-D -glucose (FDG-PET) for the evaluation of recurrence after curative resection of cancer of the esophagus or gastroesophageal junction. METHODS: Forty-one patients with a clinical or radiologic suspicion of recurrent disease underwent conventional diagnostic work-up, including a spiral computed tomographic scan, an endoscopic ultrasound, and a dedicated whole-body FDG-PET. PET lesions were classified as equivocal or suspicious recurrence. The conventional diagnostic work-up and PET findings were correlated with pathology or with radiologic and clinical follow-up. Equivocal lesions were classified as positive. RESULTS: Forty recurrences were found in 33 patients. The lesions were perianastomotic (n = 9), regional (n = 12), and at distant sites (n = 19). For the diagnosis of a perianastomotic recurrence, the sensitivity, specificity, and accuracy of FDG-PET were 100%, 57%, and 74%, versus 100%, 93%, and 96% for conventional diagnostic work-up, respectively (P = not significant). False-positive PET lesions were found in patients with a progressive anastomotic stenosis requiring repetitive endoscopic dilatation. For the diagnosis of regional and distant recurrences, the sensitivity, specificity, and accuracy of PET were 94%, 82%, and 87%, versus 81% (P = not significant), 82% (P = not significant), and 81% (P =.0771) for conventional diagnostic work-up. All false-positive PET lesions (n = 4) had been reported as equivocal. On a patient base, PET provided additional information in 11 of 41 (27%) patients. A major impact on diagnosis was found in 5 patients with equivocal or negative findings on complete diagnostic work-up in whom PET provided a true-positive diagnosis. In 5 other patients the diagnosis was staged upward from localized to extended recurrent disease, and in 1 patient with an equivocal complete diagnostic work-up, PET correctly excluded malignancy. CONCLUSION: FDG-PET allows a highly sensitive diagnosis and accurate whole-body staging of symptomatic recurrent esophageal cancer. Further studies in asymptomatic patients are needed to assess the potential benefit on survival.     

Positron emission tomography for preoperative lymph node diagnosis in esophageal carcinoma]

BACKGROUND: Exact preoperative staging is a prerequisite for the indication and the choice of appropriate operative technique for patients with esophageal carcinoma. The objective of this prospective study was to assess whether positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) increases the accuracy of preoperative lymph node staging with standard computed tomography (CT) and thus leads to a different surgical approach. PATIENTS AND METHODS: Fifty-eight patients with carcinoma of the esophagus (46 men and 12 women) with a median age of 61 years underwent FDG-PET imaging of the neck, chest, and abdomen as well as CT of the chest and abdomen. Sensitivity, specificity, and accuracy were calculated for both imaging techniques to evaluate the detection of histologically verified lymph node metastases. RESULTS: The FDG-PET showed higher specificity, whereas CT proved to be more accurate for detecting lymph node metastases not only of the abdomen (73% vs 59%) but also of the thorax (73% vs 63%). Resections were transhiatal in 23 patients and transthoracal in 16. As a supplement to conventional CT diagnostic procedure, FDG-PET was not decisive for the surgical approach. CONCLUSIONS: Altogether, pretherapeutical PET imaging did not increase the accuracy of lymph node staging for our patients with esophageal carcinoma, which had already been defined through CT. Therefore, no new consequences resulted for the surgical procedure. Due to the high costs involved with PET investigation, lymph node staging with it is momentarily indicated mainly for clinical studies and when CT does not offer unequivocal results. Increased sensitivity of the already advantageous whole-body FDG-PET imaging by means of tumor-affinitive radiopharmaceuticals and optimized apparatus resolution could lead to new indications for this staging procedure.     

Prospective evaluation of positron emission tomography in the preoperative staging of esophageal carcinoma

HYPOTHESIS: Positron emission tomography (PET) is a useful tool in the selection of patients with esophageal cancer who may not benefit from esophageal resection. DESIGN: Case series. SETTING: Tertiary care hospital. PATIENTS: Eighty-one patients with newly diagnosed esophageal cancer who underwent PET and computer tomography (CT) of the chest and abdomen (and of the neck in 45 patients) within 45 days were included. MAIN OUTCOME MEASURES: We calculated the sensitivity and specificity in detecting metastatic sites on the basis of 31 histologically verified lesions. In addition to results obtained on CT, the information provided by PET was evaluated with a view to the choice of management strategies. RESULTS: The PET findings had a higher specificity (89% vs 11%) but a lower sensitivity (38% vs 63%) than CT findings in the detection of metastatic sites. The CT results showed greater agreement with histopathological findings than did PET results. In 8 patients (10%), PET detected distant metastases that were not identified with CT. In 4 patients (5%), PET detected bone metastases only, but in all of these patients metastases in other locations were detected by CT. Although PET led to upstaging (M1) in 2 patients (2%), it did not enable the exclusion of esophageal resection. CONCLUSIONS: Preoperative PET was not characterized by greater accuracy in the detection of metastatic sites previously identified by CT. Therefore, PET did not lead to a change in the indication for esophagectomy. An increase in the sensitivity and the combined use of CT and PET may lead to new indications for this staging procedure.     

前列腺癌分子影像学的PET研究进展

前列腺癌是男性泌尿系统中最常见的恶性肿瘤。它的生物学行为与临床情况有很大的异质性,这一特点使前列腺癌的早期诊断、鉴别诊断、治疗及预后评价面临挑战。PET是反映肿瘤生物学的一种理想的非侵入性的功能显像方法,目前已有多种分子影像途径及药物用于前列腺癌的定位诊断及疗效监测。本文综述国内外有关前列腺癌分子影像学的最新PET研究进展并展望其发展前景。     

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.     

Positron emission tomography in clinical oncology

A NEW FORM OF MEDICAL IMAGING: Positron emission tomography (PET) is used for the non-invasive in vivo visualisation of biochemical cell processes. It reveals the metabolic characteristics of neoplastic lesions and hence their identification by compensating the lack of lesion specificity of radiological techniques. VARIOUS INDICATIONS: Using the current oncology marker, 18F-fluorodeoxyglucose (FDG), excellent results with PET have been established at all stages of neoplasia, notably for the diagnosis of initial malignancy and the identification of residual lesions and early detection of relapses. Moreover, the fact that the whole of the body can be explored makes PET the tool of choice in the control of the extension and operability of cancers. With the close correlation between imaging and the metabolism of the lesions, PET is the earliest and most precise for assessing the effects of treatment. LIMITS AND PERSPECTIVES: The existence of benign inflammatory FDG binding should lead to the development of markers of other metabolisms directly linked to cell proliferation. The lack of anatomical reference points characteristic of PET does not permit the precise localisation of the lesions detected and could be corrected by combining, in a single apparatus, the PET camera and an X scan, the anatomical resolution of which is irreplaceable. This type of equipment represents the development of a new branch of medical imaging, oncological imaging.     

Positron emission tomography in urological malignancy

Positron emission tomography is a unique imaging modality with the capability of studying regional metabolism. The major clinical applications of positron emission tomography have been in the detection of brain, breast, cardiac, lung and colorectal tumours, as well as the evaluation of coronary artery disease by imaging the metabolism of heart muscle. In the field of urology, positron emission tomography has been evaluated in the relevant malignancies with promising results in certain areas and disappointing results in others. This article attempts to summarize recent advances in positron emission tomography scanning with regards to urological malignancy. At this stage positron emission tomography scanning is capable of visualizing urological tumours and associated lymph nodes and distal metastatic sites. However, its use is severely limited by the excretion of the most commonly used radioisotope via the urinary tract, making pelvic imaging particularly unrewarding. It is, however, undoubtedly capable of diagnosing malignancy in soft tissue masses or lymph nodes before these changes become apparent on conventional cross-sectional imaging modalities (computerized tomography or magnetic resonance imaging). Larger studies are required before it can be advocated for clinical use in the field of urology.     

Evaluation of 18 F-fluorodeoxyglucose positron emission tomography and computed tomography with histopathologic correlation in the initial staging of head and neck cancer

OBJECTIVE: To prospectively evaluate the use of 18F-Fluorodeoxyglucose positron emission tomography (FDG-PET) in the initial staging of squamous cell head and neck carcinoma. SUMMARY BACKGROUND DATA: The status of cervical lymph nodes is an important prognostic factor and determinant of management approach in squamous cell head and neck cancer. METHODS: FDG-PET findings were compared with those of computed tomography (CT) before removal of the primary tumor and/or neck dissection. Histopathologic analysis was used as the gold standard for assessment of the sensitivity and specificity of these modalities. RESULTS: FDG-PET correctly identified the primary tumor in 35 of 40 patients in whom the site of the primary was known clinically and still present (sensitivity 88%). None of four unknown primaries were detected. Tumors not detected by FDG-PET were generally superficial, with depths of less than 4 mm. CT correctly identified 18 of the 35 primary tumors (sensitivity 51%). Eleven of 17 CT false-negative tumors were detected by FDG-PET. The sensitivity and specificity for the presence of metastatic neck disease on FDG-PET were 82% and 100%, respectively; those for CT were 81% and 81%, respectively. FDG-PET was true positive for metastatic neck disease in two of the three CT false-negative patients. CONCLUSIONS: FDG-PET shows promise in the initial staging of head and neck cancer and provides additional accuracy to a conventional staging process using CT.     

Diagnosis of esophageal cancer using positron emission tomography

Fluorodeoxyglucose positron emission tomography (FDG-PET) is more accurate than computed tomography (CT) for evaluating lymph node metastases and for N staging, but less accurate than combined CT and endoscopic ultrasonography (EUS). Lymph nodes located adjacent to the primary lesion tend to be false negatives. We consider that combined FDG-PET and EUS is the most accurate for the detection of lymph node metastasis in esophageal cancer. FDG-PET is also more accurate than CT for detecting distant metastases and improves the detection of stage IV disease compared with the conventional staging modalities. For the diagnosis of recurrence except for perianastomotic recurrence, FDG-PET provides additional information and is more sensitive than conventional work-ups. FDGPET is a valuable tool for the noninvasive assessment of tumor response after neoadjuvant therapy. 11C-methionine (MET) is another tracer for PET that can be used to assess the metabolism of amino acids, since MET accumulates in esophageal malignant tumors. Choline-PET is more accurate than FDG-PET for the detection of mediastinal lymph node metastases.     

Positron emission tomography with f18-fluorodeoxyglucose in the staging and preoperative evaluation of malignant pleural mesothelioma

OBJECTIVES: The purpose of this study was to evaluate the utility of positron emission tomography with F18-fluorodeoxyglucose in the preoperative evaluation and staging of malignant mesothelioma in patients who were candidates for aggressive combined modality therapy. METHODS: Eighteen consecutive patients with biopsy-proven malignant mesothelioma underwent positron emission tomographic scanning. The results of positron emission tomographic imaging were compared with results obtained by computed tomography, mediastinoscopy, thoracoscopy, and pathologic examination of surgical specimens. All patients fasted and received an average of 14.5 +/- 2.7 mCi of F18-fluorodeoxyglucose for positron emission tomographic scanning. Attenuation-corrected whole-body and regional emission images of the chest and upper abdomen were acquired and formatted into transaxial, coronal, and sagittal images. RESULTS: All primary malignant mesotheliomas accumulated F18-fluorodeoxyglucose, and the mean standardized uptake value was 7. 6 (range, 3.33-14.85; n = 9). There were no false-negative results of positron emission tomography. Identification of occult extrathoracic metastases by positron emission tomography was the basis for excluding two patients from surgical therapy. There were two false-positive results of positron emission tomography: increased F18-fluorodeoxyglucose uptake in the contralateral chest that was negative by thoracoscopic biopsy (n = 1) and increased abdominal F18-fluorodeoxyglucose uptake after partial colectomy for diverticular disease (n = 1). CONCLUSIONS: Positron emission tomography can identify malignant pleural mesothelioma and appears to be a useful noninvasive staging modality for patients being considered for aggressive combined modality therapy.