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.     

High-resolution fluorodeoxyglucose positron emission tomography with compression ("positron emission mammography") is highly accurate in depicting primary breast cancer

We sought to prospectively assess the diagnostic performance of a high-resolution positron emission tomography (PET) scanner using mild breast compression (positron emission mammography [PEM]). Data were collected on concomitant medical conditions to assess potential confounding factors. At four centers, 94 consecutive women with known breast cancer or suspicious breast lesions received 18F-fluorodeoxyglucose (FDG) intravenously, followed by PEM scans. Readers were provided clinical histories and x-ray mammograms (when available). After excluding inevaluable cases and two cases of lymphoma, PEM readings were correlated with histopathology for 92 lesions in 77 women: 77 index lesions (42 malignant), 3 ipsilateral lesions (3 malignant), and 12 contralateral lesions (3 malignant). Of 48 cancers, 16 (33%) were clinically evident; 11 (23%) were ductal carcinoma in situ (DCIS), and 37 (77%) were invasive (30 ductal, 4 lobular, and 3 mixed; median size 21 mm). PEM depicted 10 of 11 (91%) DCIS and 33 of 37 (89%) invasive cancers. PEM was positive in 1 of 2 T1a tumors, 4 of 6 T1b tumors, 7 of 7 T1c tumors, and 4 of 4 cases where tumor size was not available (e.g., no surgical follow-up). PEM sensitivity for detecting cancer was 90%, specificity 86%, positive predictive value (PPV) 88%, negative predictive value (NPV) 88%, accuracy 88%, and area under the receiver-operating characteristic curve (Az) 0.918. In three patients, cancer foci were identified only on PEM, significantly changing patient management. Excluding eight diabetic subjects and eight subjects whose lesions were characterized as clearly benign with conventional imaging, PEM sensitivity was 91%, specificity 93%, PPV 95%, NPV 88%, accuracy 92%, and Az 0.949 when interpreted with mammographic and clinical findings. FDG PEM has high diagnostic accuracy for breast lesions, including DCIS.     

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.     

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.     

Peritoneal recurrence of colon cancer detected by positron emission tomography: Report of a case

Increased glucose metabolism has been reported to occur in association with colorectal cancer. As positron emission tomography (PET) using [¹⁸F]fluorodeoxyglucose is able to depict hypermetabolic sites, it can therefore be used to detect colorectal cancer. A 69-year-old male patient with a recurrent solitary liver metastasis from colon cancer underwent whole-body PET which revealed high [¹⁸F]fluorodeoxyglucose uptake in the lesion. Furthermore, PET revealed peritoneal metastases that had not been detected by conventional imaging methods. Consequently, PET proved useful in helping us to avoid performing unnecessary treatment for the liver metastasis. Although it is uncertain whether early identification of recurrence can prolong survival, it may help to prevent unnecessary treatments being carried out. Thus, the application of PET in carefully selected patients could be beneficial to the management of recurrent colorectal cancer.     

The use of positron emission tomography in detecting hepatoblastoma recurrence--a cautionary tale

Purpose

The use of positron emission tomography (PET) with [18F] fluorodeoxyglucose (FDG) in the detection of recurrences has been well established in many tumor types. Here the authors present their experience using this modality in the evaluation of posttreatment hepatoblastoma patients.

Methods

The authors conducted a retrospective review on patients with hepatoblastoma diagnosed from 1996 to 2003. FDG-PET imaging was performed together with measurement of alpha-fetal protein (AFP) during posttreatment follow-up.

Results

Sixteen patients (8 boys and 8 girls) were identified in this series. The mean age was 23.5 months (range, 5 months to 4 years). Three posttreatment patients had PET results suggestive of tumor recurrence. One of these patients had normal AFP level and suspected recurrence in the caudate lobe. Radiologic-guided biopsy was performed 3 times, and there was no evidence of tumor. The other 2 patients underwent further liver resections because of mildly raised AFP levels. The histology of these showed regenerative liver tissue only with no hepatoblastoma recurrence.

Conclusions

Although PET has been gaining popularity as a tool in the detection of tumor recurrences worldwide, it has been shown in this series that PET may not be useful in hepatoblastoma patients, and caution must be taken in the interpretation of positive results.     

Assessment of residual liver functional reserve after portal embolization with positron emission tomography usingl-[methyl-11C] methionine and computed tomography

Hepatic functional reserve after portal embolization was assessed in eight patients according to the functional volume index (FVI), a new index obtained using positron emission tomography (PET) withl-[methyl-¹¹C] methionine. FVI in residual liver was 1744–5252 (mean, 3441) (normal range, 3106–6211) before percutaneous transhepatic portal embolization (PTPE) and 2457–6906 (mean, 4590) after PTPE. FVI exceeded 4000 in five patients and did not reach 4000 in three patients after PTPE. Two patients with FVI values of more than 4000 survived after hepatectomy and one with FVI under 4000 died of liver failure. FVI is a useful criterion for determining indications for PTPE; a value exceeding 4000 is needed before major hepatectomy can be safely performed after PTPE.     

氟脱氧葡萄糖和乙酸盐联合在正电子发射型计算机体层显像诊断肝细胞癌的效能：Meta分析

目的通过meta分析的方法,系统评价^11F—FDG和^11C—Acetate正电子发射型计算机体层扫描联合诊断肝细胞癌的效能。方法使用相关检索词对Medline Pubmed和中国知识基础设施数字图书馆（CNKI）进行检索,收集近年来公开发表的相关中英文文献,并对纳入文献质量进行评分,提取纳入文献的研究数据进行meta分析。结果共有5篇文献纳入本次meta分析。其中英文4篇。中文1篇;对纳入文献进行质量评分,文献得分占总分的78．8％,两种正电子药物联合显像对肝细胞癌的显示率可达到82．9％;肿瘤直径小于2cm、2.5cm之间及5cm以上的肝细胞癌FDG显示阳性率为25％、45．9％、80．9％,Acetate为79．2％、80．1％、78．7％;1、2级分化的肝细胞癌,FDG显示阳性率为48％,Acetate为73．3％;3、4级分化的肝细胞癌,FDG显示阳性率为89．5％,Acetate为86．8％;肝功能Child A级时,FDG显示肝细胞癌的阳性率为59％,Acetate为72％。结论Acetate和FDGPET对肝细胞癌显像有重要的补充作用,二者联合能提高肝细胞癌的显像效能。     

Evolving role of positron emission tomography (PET) in urological malignancy

We present a review on the increasing indications for the use of positron emission tomography (PET) in uro‐oncology. In this review we describe the details of the different types of PET scans, indications for requesting PET scans in specific urological malignancy and the interpretation of the results.     

Use of positron emission tomography (PET) in stereotactic conditions for brain biopsy

Summary In order to take advantage of the metabolic information provided by positron emission tomography (PET) in cases of brain tumour, we have developed a technique to integrate PET images routinely in the planning of stereotactic brain biopsy. We used stereotactic PET with [¹⁸F]-labelled fluorodeoxyglucose (PET-FDG) in 38 patients undergoing brain biopsy. To evaluate the contribution of PET-FDG in guiding brain biopsy, we analyzed the diagnosis provided by the 78 Stereotactic trajectories obtained in these patients.We found that stereotactic PET-FDG seemed to provide more information in cases of anaplastic astrocytomas and glioblastomas than in low-grade gliomas. Our results also show that biopsy trajectories performed in areas where increased FDG uptake is found within the lesion boundaries always provide interpretable specimens; this was not the case for trajectories guided by CT only. Therefore, the routine integration PET-FDG in the planning of stereotactic brain biopsy may lead to a reduction in sampling. Recently, we also tested consecutive stereotactic PET with [¹¹C]-labelled methionine (PET-Met) and PET-FDG. This technique allowed us to compare accurately the tumoural glucose metabolism and protein synthesis.Our results suggest that stereotactic PET may increase the diagnostic yield of brain biopsy and may improve the understanding of PET in neuro-oncology.     

False positive accumulation in 18F fluorodeoxyglucose positron emission tomography scan due to sarcoid reaction following induction chemotherapy for lung cancer

We present a case of lung cancer that showed false positive accumulation in an ¹⁸F fluorodeoxyglucose positron emission tomography (FDG-PET) scan following induction chemotherapy for suspected metastasis and progression of malignancy. A 66-year-old man was diagnosed with squamous cell carcinoma in the lung, classified as clinical stage IIIA (T2N2M0), and underwent induction chemotherapy. An FDG-PET scan prior to chemotherapy demonstrated accumulation only in the tumor, whereas following treatment it revealed a strong accumulation not only in the tumor, but also in the supraclavicular lymph nodes, which indicated lymph node metastasis. The patient underwent a biopsy of the right supraclavicular lymph node and mediastinoscopy, after which all dissected lymph nodes showed sarcoid reactions and no tumor cells were found pathologically. We concluded that when evaluating the effect of induction chemotherapy for malignancy, a sarcoid reaction might lead to the false positive accumulation of FDG.     

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.     

Positron emission tomography in the study of cerebral tumours

Summary Positron emission tomography (PET) uses the shortlived positron-emitting radioisotopes of elements such as oxygen, nitrogen, and carbon as tracers both to image and to measure, non-invasively, normal regional tissue physiology and pathophysiology in man. This technique has been used to study the pathophysiology of brain tumours at the time they present and after therapeutic intervention.     

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。     

18-fluorodeoxyglucose positron emission tomography in predicting survival of patients with pancreatic carcinoma

The prediction of survival of patients with pancreatic cancer is usually based on tumor staging and grading and on the level of tumor markers. However, accurate tumor staging can be obtained only after resection, and still there is a great difference in survival rates among patients with the same clinicopathologic parameters. Recently the uptake of 18-fluorodeoxyglucose (FDG) by positron emission tomography (PET) has been found to be correlated with survival in patients with pancreatic cancer. This study evaluated the role of ¹⁸FDG PET as a prognostic factor for patients with pancreatic cancer. From June 1996 to July 2002, a total of 118 patients underwent PET for pancreatic cancer. The standardized uptake value (SUV) of ¹⁸FDG was calculated in 60 of them, and these patients were divided into high (>4) and low (≦4) SUV groups. They were also evaluated according to the tumor node metastasis (TNM) classification system of the International Union Against Cancer, and by tumor grade, medical or surgical treatment, diabetes, age, sex, and CA19-9 serum levels. Twenty-nine cancers showed high and 31 showed low SUVs. Survival was significantly influenced by tumor stage (P = 0.0001), tumor grade (P = 0.01), and SUV (P = 0.005). Multivariate analysis showed that only stage (P = 0.001) and SUV (P = 0.0002)were independent predictors of survival. When patients who were analyzed for SUV were stratified according to the other variables, FDG uptake was related to survival also after stratification for the following: stage III to IVa (P = 0.002), stage IVb (P = 0.01), tumor resection (P = 0.006), moderately differentiated tumors (P = 0.01), age less than 65 years (P = 0.006), CA 19–9 levels greater than 300 kU/L (P = 0.002), and absence of diabetes (P = 0.0001). The SUV calculated with ¹⁸FDG PET is an important prognostic factor for patients with pancreatic cancer and may be useful in selecting patients for therapeutic management. Presented at the Forty-Fourth Annual Meeting of The Society for Surgery of the Alimentary Tract, Orlando, Florida, May 17–22, 2003 (oral presentation); and the Sixth National Congress of the Italian Association of Nuclear Medicine, Genoa, Italy, November 15–19, 2002.     

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.     

18F-FDGPET/CT与传统影像检查寻找骨转移瘤原发灶的比较

[目的]比较18F-FDG PET/CT与传统影像检查(胸片、彩超、CT及MRI等)为骨转移瘤患者寻找原发灶的临床价值.[方法]回顾性分析37例于2008年5月～2010年6月间本中心收治的经病理证实的骨转移瘤患者的病例资料,并随访其后续的诊治情况.以病理结果或临床随访作为原发灶确认标准.并将PET/CT与传统影像检查对原发灶的检出情况进行比较.且对治疗方案的调整进行汇总.[结果]37例患者中,PET/CT提示原发灶28例,其中正确检出原发灶27例(73％),1例为假阳性;传统影像检查正确检出原发灶17例(46％),两者原发灶正确检出率的差异有显著性(x2=5.61,P=0.018).27例经PET/CT正确检出原发灶的病例中,17例(63％)采取了针对原发灶的治疗措施.此外9例PET/CT未提示原发灶的患者中,3例经病理证实为假阴性.[结论]与传统影像检查相比,18F-FDG PET/CT可更有效、更便捷的找出骨转移瘤患者原发灶,进而为制定更合理的治疗方案提供依据.