Role of positron emission tomography in urological oncology

??Positron emission tomography (PET) is a diagnostic tool using radiotracers to show changes in metabolic activities in tissues. We analysed the role of PET and PET/computed tomography (CT) in the diagnosis, staging, and follow-up of urological tumours. ??A critical, non-structured review of the literature of the role of PET and PET/CT in urological oncology was conducted. ??PET and PET/CT can play a role in the management of urological malignancies. For prostate cancer, the advances in radiotracers seems promising, with novel radiotracers yielding better diagnostic and staging results than 18F-fluorodeoxyglucose (18F-FDG). In kidney cancer, PET and PET/CT allow a proper diagnosis before the pathological examination of the surgical specimen. For testis cancer, PET and PET/CT have been shown to be useful in the management of seminoma tumours. In bladder cancer, these scans allow a better initial diagnosis for invasive cancer, while detecting occult metastases. ??PET and its combined modality PET/CT have shown their potential in the diagnosis of urological malignancies. However, further studies are needed to establish the role of PET in the management of these diseases. Future applications of PET may involve fusion techniques such as magnetic resonance imaging with PET.     

临界可切除胰腺癌的诊疗策略

胰腺癌早期诊断困难,80%的患者就诊时已发生局部进展或远处转移。目前,手术切除仍是胰腺癌患者获得长期生存的唯一方法。近年来,胰腺癌综合治疗水平较前有所提高。针对临界可切除胰腺癌进行新辅助治疗,可以达到降期,甄别人群,筛选潜在获益人群进行手术的目的。合理选择有效化疗方案,恰当选择手术时机,能进一步提高胰腺癌的切除率,从而延长该类高危人群的生存期。     

Adjuvant treatments for resectable pancreatic cancer

Pancreatic cancer remains one of the most challenging malignancies to treat successfully. The majority of patients present with unresectable advanced-stage cancer, and only 20% of patients can undergo resection. Even if surgical resection is performed, the recurrence rate is high and the survival rate after surgery is poor. Therefore, effective adjuvant therapy is needed to improve the prognosis of patients with pancreatic cancer. Until now, no universally accepted standard adjuvant therapy for this disease has been available: chemoradiotherapy followed by chemotherapy is considered the optimal therapy in the United States, while chemotherapy alone is the current standard in Europe. However, recent randomized controlled trials (RTOG [Radiation Therapy Oncology Group] 9704; CONKO [Charité Onkologie]-001; and a Japanese study) have suggested a benefit of adjuvant chemotherapy with gemcitabine for patients with resectable pancreatic cancer. This article will review the clinical trials of adjuvant therapy for this disease, including the results of recent trials.     

18F-FDG PET在胰腺癌患者预后评估中的价值

目的 评估18F-FDG PET判断胰腺癌患者预后的价值.方法 回顾性分析54例胰腺癌病例资料.取所有病例PET检查的标准摄取值(standard uptake value,SUV)平均值4为截断点分组,A组22例(SUV≤4),B组32例(SUV＞4),分析两组患者的预后.结果 A组1、3年生存率为68.18%、34.91%;B组1、3年生存率为33.61%、11.95%,两组生存率比较差异有统计学意义(P=0.01);Cox回归分析提示肿瘤分期和SUV是胰腺癌患者预后的独立危险因素.结论 18F-FDG PET在判断胰腺癌预后方面有一定的价值.     

The role of positron emission tomography in germ cell cancer

Positron emission tomography (PET) is a non-invasive tool for imaging regional metabolic processes, which adds another dimension to current anatomy-derived imaging techniques, i.e. metabolic imaging. To date, 2-¹⁸fluoro-2-deoxy-D-glucose (FDG) has been the only tracer used for imaging germ cell tumors (GCT), which can be distinguished from normal tissue by their different glucose utilization. However, FDG PET has several limitations: (1) inflammatory and granulomatous tissues also show extensive FDG uptake, (2) lesions <1 cm in size can often not be detected, and (3) mature teratoma is indistinguishable from normal and necrotic tissue. Studies assessing the clinical role of FDG PET in GCT suggest that the technique has a place as a standard tool in evaluating post chemotherapy seminoma residuals. Whether it also improves the assessment of the risks carried by clinical stage I non-seminoma patients and the early prediction of response to salvage chemotherapy is still under investigation, or at least needs to be confirmed by further trials. In relapsing patients with a mismatch between tumor markers and imaging data, FDG PET appears to be useful whenever salvage surgery is considered, although systematic trials are not yet available.     

Comparison of preoperative whole-body positron emission tomography with MDCT in patients with primary colorectal cancer

Objective  Preoperative use of emission tomography with¹⁸F-fluorodeoxyglucose (FDG-PET) in patients with primary colorectal cancer remains controversial. This study evaluated the additional value of FDG-PET in comparison with routine multidetector row computed tomography (MDCT) in patients with primary colorectal cancer.
Method  Retrospective analysis was performed in 65 patients with colorectal cancer who underwent whole-body FDG-PET. Results of FDG-PET were compared with routine preoperative evaluation by MDCT regarding detection of primary tumour, lymph node involvement and distant metastases. All images were evaluated before surgery.
Results  Tumour detection rate was 100% (63/63) for MDCT and 98% (62/63) for FDG-PET. Lymph node involvement was pathologically confirmed in 35 patients. MDCT and FDG-PET displayed sensitivities of 89% (31/35; 95% CI: 73–97%) and 43% (15/35; 95% CI: 26–61%) and specificities of 52% (11/21; 95% CI: 30–74%) and 95% (20/21; 95% CI: 76–100%), respectively. Liver metastases were present in 22 patients. MDCT and FDG-PET showed accuracies of 98% (64/65; 95% CI: 92–100%) and 97% (63/65; 95% CI: 89–100%), respectively. FDG-PET detected additional extrahepatic metastatic lesions and affected treatment plan compared with MDCT in 10 patients.
Conclusion  Preoperative FDG-PET is not superior to MDCT for detection of primary tumour, lymph node involvement or liver metastases, but may have potential clinical value in patients with advanced colorectal cancer by detecting extrahepatic distant metastases.     

An engineered anti-CA19-9 cys-diabody for positron emission tomography imaging of pancreatic cancer and targeting of polymerized liposomal nanoparticles

Background

Antibody-based therapeutics is a rapidly growing field. Small engineered antibody fragments demonstrate similar antigen affinity compared with the parental antibody but have a shorter serum half-life and possess the ability to be conjugated to nanoparticles. The goal of this study was to engineer an anti-carbohydrate antigen 19-9 (CA19-9) cys-diabody fragment in hopes of targeting nanoparticles to pancreatic cancer.

Methods

The anti-CA19-9 cys-diabody was created by engineering a C-terminal cysteine residue into the DNA single-chain Fv construct of the anti-CA19-9 diabody and expressed in NS0 cells. Maleimide chemistry was used to conjugate the cys-diabody to polymerized liposomal nanoparticles (PLNs) through the cysteine residues. Flow cytometry was used to evaluate targeting of cys-diabody and cys-diabody–PLN conjugate to human pancreatic cancer cell lines. The cys-diabody was radiolabeled with a positron emitter (¹²⁴I) and evaluated in a mouse model of CA19-9–positive and CA19-9–negative xenografts with micro–positron emission tomography/micro–computed tomography at successive time intervals after injection. Percentage of injected dose per gram of radioactivity was measured in blood and tumor to provide objective confirmation of the micro–positron emission tomographic images.

Results

Tumor xenograft imaging of the anti-CA19-9 cys-diabody demonstrated an average tumor-to-blood ratio of 3.0 and positive-to-negative tumor ratio of 7.4. Successful conjugation of the cys-diabody to PLNs was indicated by flow cytometry showing specific binding of cys-diabody–PLN conjugate to human pancreatic cancer cells in vitro.

Conclusions

Our results show that the anti-CA19-9 cys-diabody targets pancreatic cancer providing specific molecular imaging in tumor xenograft models. Furthermore, the cys-diabody–PLN conjugate demonstrates target-specific binding of human pancreatic cancer cells with the potential to deliver targeted treatment.     

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.     

Trends in treatment for pancreatic cancer

Although surgical resection is considered to be the only approach that offers a possibility of cure to patients with pancreatic cancer, the prognosis of the disease has not been improved markedly by any surgical procedures in the past 20 years. Large-scale randomized prospective clinical trials are being conducted in the United States and Italy, comparing standard lymph node dissection with extended lymph node dissection. Although preoperative chemoradiation has various advantages in the treatment of pancreatic cancer, it does not contribute to its downstaging and eventual cure. The combination of leucovorin, 5-fluorouracil (5-FU), and extracorporeal irradiation, however, has been proven to improve the patient's quality of life (QOL). Palliative surgery still requires further research in areas such as the examination of morbidity rates and the duration of bypass effects, now that laparoscopic and endoscopic surgery have both been well developed. Recent biological research has revealed the mechanisms of the carcinogenesis and the progression of pancreatic cancer, and, against this background, we assume that more effective trials will be conducted soon. Immunotherapy with dendritic cells, as well as gene therapy with mutant adenovirus, has already been employed clinically. Pancreatic cancer therapy is now facing new prospects. Received: February 15, 2001 / Accepted: April 10, 2001     

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.     

Limited value of positron emission tomography in treatment of pancreatic cancer: surgeon's view

We aimed to assess, from a surgical point of view, the value of positron emission tomography (PET) in the routine preoperative diagnostic evaluation of a pancreatic mass. In particular, we were interested in PET's ability to distinguish a malignancy from a nonmalignant process and its impact on surgical decision making. We documented prospectively the results of preoperative ultrasonography, computed tomography (CT), endoscopic retrograde cholangiopancreatography (ERCP), and PET in terms of a correct diagnosis of malignancy in 103 patients. All patients underwent surgery at our department and had a complete histologic workup. We then related the preoperative findings to the intraoperative and histologic findings and analyzed the advantages and limitations of PET in comparison with conventional diagnostic techniques. Both CT and PET showed high sensitivities (82% and 84%, respectively) but rather low specificities (61%). ERCP showed good specificity at 83% but weak sensitivity at 46%. The positive predictive value was higher than 80% for all methods, whereas the negative predictive value was around 60% at best. Both the CT and the PET diagnoses were wrong in 15% of the cases. In all cases with a false CT diagnosis, the results of the other conventional examinations provided sufficient evidence to indicate the need for surgical intervention. In all cases where PET gave misleading results, CT findings indicated the need for surgery. PET overlooked pT1 cancers in three of the patients. PET does not reliably prove or exclude malignancy in situations where conventional diagnostic procedures leave doubt as to the nature of a pancreatic mass. PET does introduce a new procedure-related spectrum of misinterpretations to the diagnostic process.     

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.     

Update on positron emission tomography for imaging of prostate cancer

Prostate cancer is the most common non‐cutaneous malignancy among men in the Western world, and continues to be a major health problem. Imaging has recently become more important in the clinical management of prostate cancer patients, including diagnosis, staging, choice of optimal treatment strategy, treatment follow up and restaging. Positron emission tomography, a functional and molecular imaging technique, has opened a new field in clinical oncological imaging. The most common positron emission tomography radiotracer, ¹⁸F‐fluorodeoxyglucose, has been limited in imaging of prostate cancer. Recently, however, other positron emission tomography tracers, such as ¹¹C‐acetate and ¹¹C‐ or ¹⁸F‐choline, have shown promising results. In the present review article, we overview the potential and current use of positron emission tomography or positron emission tomography/computed tomography imaging employing the four most commonly used positron emission tomography radiotracers, ¹⁸F‐fluorodeoxyglucose, ¹¹C‐acetate and ¹¹C‐ or ¹⁸F‐choline, for imaging evaluation of prostate cancer.     

Detection of recurrent and metastatic colorectal cancer: Comparison of positron emission tomography and computed tomography

Background: This study evaluates the clinical value of positron emission tomography (PET) with 2-[F-18] fluoro-2-deoxy-D-glucose (FDG) as compared to computed tomography (CT) in patients with suspected recurrent or metastatic colorectal cancer (CRC). Methods: A retrospective review of the records of 58 patients who had FDG-PET for evaluation of recurrent or advanced primary CRC was performed. FDG-PET results were compared with those of CT and correlated with operative and histopathologic findings, or with clinical course and autopsy reports. Results: Recurrent or advanced primary CRC was diagnosed in 40 and 11 patients, respectively. The sensitivity and specificity of FDG-PET were 91% and 100% for detecting local pelvic recurrence, and 95% and 100% for hepatic metastases. These values were superior to CT, which had sensitivity and specificity of 52% and 80% for detecting pelvic recurrence, and 74% and 85% for hepatic metastases. FDG-PET correctly identified pelvic recurrence in 19 of 21 patients; CT was negative in 6 of these patients and equivocal in 4. FDG-PET was superior to CT in detecting multiple hepatic lesions and influenced clinical management in 10 of 23 (43%) patients. Conclusion: FDG-PET is more sensitive than CT in the clinical assessment of patients with recurrent or metastatic CRC, and provides an accurate means of selecting appropriate treatment for these patients. Presented at the 50th Annual Cancer Symposium of The Society of Surgical Oncology, Chicago, Illinois, March 20–23, 1997.     

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.     

抽动秽语综合征PET脑代谢显像的研究

目的:利用PET技术观察抽动秽语综合征(TS)患者脑功能异常的部位.方法:经临床确诊TS患者65例,利用18氟-脱氧葡萄糖(18F-FDG)行PET脑显像,图像采集自动重建后,目视观察18F-FDG在PET脑显像图像中的代谢分布.结果:65例TS患者中PET脑显像异常者61例(93.8%).异常部位代谢分布表现为放射性...