Pitfalls of Positive Findings in Staging Esophageal Cancer With F-18-Fluorodeoxyglucose Positron Emission Tomography

Background: 18-F-fluorodeoxyglucose positron emission tomography (FDG-PET) is valuable in staging of esophageal cancer. However, FDG-PET may falsely upstage patients leading to incorrect exclusion from surgical treatment. This study was performed to determine the false-positive rate and possible causes.Methods: The rate of false-positive lesions on FDG-PET was documented in 86 out of a group of 98 patients. Lesions were defined as false positive when pathological examination was negative or as absence of tumor activity within 6 months of follow-up. To evaluate the influence of a learning curve on the false-positive rate, the PET scans were revised recently.Results: False-positive lesions were found in 13 patients (13 of 86; 15%). FDG-PET incorrectly revealed only locoregional node metastases in 5 patients in whom surgery with curative intent was performed. Ten lesions in the other 8 patients were classified as distant organ or as nonregional node metastases (M1a/1b). Finally, 5 patients upstaged to M1a/1b underwent a curative resection. The number of false-positive lesions decreased from 16 to 5 (6%) after revision.Conclusions: Proper interpretation of FDG-PET in staging esophageal cancer is impeded by false-positive results. Even after completion of the learning curve, positive FDG-PET findings still have to be confirmed by additional investigations.     

Evaluation of Shoulder Disorders by 2-[F-18]-fluoro-2-deoxy-D-glucose Positron Emission Tomography and Computed Tomography

Background

Although flourine-18-flourodeoxyglucose (FDG) positron emission tomography (PET) has a limitation for localizing anatomical structures, combining it with computed tomography (CT) has made it more efficient for overcoming such limitations. This study aims to evaluate the efficacy of PET/CT for evaluating diseases of the shoulder.

Methods

Retrospective examination was performed on 25 patients who underwent FDG-PET/CT scanning. All the patients were over 60 years of age, and they were evaluated both clinically and radiologically for shoulder pain. The study period was from May, 2006 to May, 2008. One of the patients had metastatic lesion in a shoulder and this patient was excluded from the study, so the total number of subjects in the study was finally 24 patients.

Results

PET/CT showed 67% sensitivity, 73% specificity, a positive predictive value of 60%, a negative predictive value of 79%, 27% false positivity and 33% false negativity concerning shoulder pain. PET/CT showed negative finding in 4 cases that were successfully treated by operative treatment (rotator cuff tear [RCT], 3 cases; impingement syndrome, 1 case). Negative findings were also noted in 6 cases in which the pain subsided after conservative treatment (RCT, 1 case; suspected RCT, 2 cases; impingement syndrome, 3 cases). All the patients with osteoarthritis and rheumatoid arthritis had positive findings on PET/CT scanning.

Conclusions

PET/CT is a useful adjunct to the existing imaging modalities to assess functional and pathophysiologic processes and at a very early stage, and so PET/CT can help physicians make better preoperative and postoperative decisions on treatment.     

Molecular Mechanism Underlying the Detection of Colorectal Cancer by 18F-2-Fluoro-2-Deoxy-d-Glucose Positron Emission Tomography

Background  

Biological imaging by positron emission tomography (PET) using 18F-2-fluoro-2-deoxy-d-glucose (FDG) has been widely used clinically for the detection of primary tumors and for early prediction of response to chemotherapy. In this study, we examined the molecular mechanism underlying the detection of colorectal cancers by FDG-PET.     

Impact of 18-Fluorodeoxyglucose Positron Emission Tomography on the Management of Pancreatic Cancer

Background  

We compared the usefulness of positron emission tomography with the glucose analogue 2-deoxy-2-[18F]-fluoro-d-glucose (FDG-PET) and multidetector-row computed tomography (MD-CT) in diagnosing pancreatic cancer and in determining the patients’ suitability for surgery.     

18-Fluorodeoxyglucose Positron Emission Tomography Predicts Recurrence in Resected Pancreatic Ductal Adenocarcinoma

Background

We aimed to determine whether treatment should be stratified according to 18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) maximum standardized uptake values (SUV_max) in pancreatic ductal adenocarcinoma.

Methods

Patients who underwent preoperative 18F-FDG PET/CT between 2006 and 2014 (n = 138) were stratified into high (≥ 4.85) and low (< 4.85) PET groups. The clinicopathological characteristics and prognostic outcomes were analyzed retrospectively.

Results

The primary tumor SUV_max was positively correlated with preoperative CA19-9 levels (P < 0.001). The high PET group failed to achieve postoperative CA19-9 normalization (P = 0.014). Disease-specific (P < 0.001), recurrence-free (P < 0.001), liver recurrence-free (P < 0.001), and peritoneal recurrence-free (P = 0.020) survivals were significantly shorter in the high PET group. The primary tumor SUV_max was an independent predictive risk factor for liver metastasis (hazard ratio 3.46, 95% confidence interval 1.61–7.87; P = 0.001) and peritoneal recurrence (hazard ratio 3.36, 95% confidence interval 1.18–10.89; P = 0.023).

Conclusions

Surgical resection failed to achieve CA19-9 normalization in the high PET group and distant recurrence was frequent. This suggests the potential for residual cancer at distant sites, even after curative resection. Stronger preoperative systemic chemotherapy is preferred for the high PET group patients.

     

Positron Emission Tomography in Lung Cancer

Reports on positron emission tomography have become more common in the oncology literature. After a short introduction to positron emission tomography, this review will look at the data relating to the use of this technology in the diagnosis, the staging, and the posttreatment evaluation of patients with lung cancer and will discuss its potential role in these evaluations.     

18F-脱氧葡萄糖正电子发射体层显像检查在肺结核患者中的应用

目的探讨18F-脱氧葡萄糖正电子发射体层显像(18F-FDG-PET)检查在肺结核患者中的应用价值。方法回顾性分析53例肺结核患者的18F-FDG-PET检查结果,采用目测法判读,半定量分析法检测肺部结核显影病灶的最大标准摄取值(SUVmax)和平均标准摄取值(SUVmean)以及相应正常肺组织标准摄取值(SUVlung)。结果36例肺结核结节在18F-FDG-PET检查中显影,目测法判断为活动性结核,半定量分析法观察结核病变的SUVmax(2.77±1.20)和SUVmean(2.15±0.86)分别高于SUVlung(0.41±0.09,Z=-5.232,P<0.01;Z=-5.232,P<0.01)。SUVmax和SUVmean与病变大小(Dmax、Dmin)、SUVlung、患者年龄、血糖水平均无明显的相关性(P>0.05)。17例无干酪样坏死的陈旧性结核纤维化和钙化病灶未显影。结论18F-FDG-PET检查可以有效地判断肺结核结节是否属活动期、确定结核累及的范围和有助于制定治疗方案。     

Fluorodeoxyglucose F18 Positron Emission Tomography Coupled With Computed Tomography in Suspected Acute Renal Allograft Rejection

Management of kidney transplant recipients (KTRs) with suspected acute rejection (AR) ultimately relies on kidney biopsy; however, noninvasive tests predicting nonrejection would help avoid unnecessary biopsy. AR involves recruitment of leukocytes avid for fluorodeoxyglucose F¹⁸ (¹⁸F‐FDG), thus ¹⁸F‐FDG positron emission tomography (PET) coupled with computed tomography (CT) may noninvasively distinguish nonrejection from AR. From January 2013 to February 2015, we prospectively performed 32 ¹⁸F‐FDG PET/CT scans in 31 adult KTRs with suspected AR who underwent transplant biopsy. Biopsies were categorized into four groups: normal (n = 8), borderline (n = 10), AR (n = 8), or other (n = 6, including 3 with polyoma BK nephropathy). Estimated GFR was comparable in all groups. PET/CT was performed 201 ± 18 minutes after administration of 3.2 ± 0.2 MBq/kg of ¹⁸F‐FDG, before any immunosuppression change. Mean standard uptake values (SUVs) of both upper and lower renal poles were measured. Mean SUVs reached 1.5 ± 0.2, 1.6 ± 0.3, 2.9 ± 0.8, and 2.2 ± 1.2 for the normal, borderline, AR, and other groups, respectively. One‐way analysis of variance demonstrated a significant difference of mean SUVs among groups. A positive correlation between mean SUV and acute composite Banff score was found, with r² = 0.49. The area under the receiver operating characteristic curve was 0.93, with 100% sensitivity and 50% specificity using a mean SUV threshold of 1.6. In conclusion, ¹⁸F‐FDG PET/CT may help noninvasively prevent avoidable transplant biopsies in KTRs with suspected AR.     

18F-2-Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography Scanning Affects Surgical Management in Selected Patients With High-Risk, Operable Breast Carcinoma

Background The role of positron emission tomography (PET) scanning in determining the extent of disease in patients with breast cancer has not been defined. We investigated the utility of ¹⁸F-2-fluoro-2-deoxy-D-glucose (FDG)-PET scanning compared with conventional imaging with computed tomographic scanning and bone scanning in determining the extent of disease in patients with high-risk, operable breast cancer. Methods This was a prospective study of patients who presented to Memorial Sloan-Kettering Cancer Center for operative treatment of breast cancer. Eighty eligible patients were enrolled and underwent computed tomographic chest, abdomen, pelvis, and bone scans, followed by FDG-PET. Changes in treatment based on scan findings were recorded by the operating surgeons. Imaging findings were verified by biopsy or long-term follow-up. Results Eight (10%) of 80 patients were found to have metastatic disease that was seen on both conventional imaging and PET. Four additional patients (5%) had additional foci of disease on PET that affected treatment decisions. No patient had findings on conventional imaging alone. Conventional imaging studies resulted in a higher number of findings that generated additional tests and biopsies that ultimately had negative results (17% vs. 5% for PET). There was a statistically significant difference in specificity for PET compared with conventional imaging (P = .01). Conclusions Conventional imaging and PET were equally sensitive in detecting metastatic disease in patients with high-risk, operable breast cancer, but PET generated fewer false-positive results. FDG-PET scanning should be further studied in this setting and considered in the preoperative evaluation of selected patients with breast cancer.     

18F-Fluorodeoxyglucose Positron Emission Tomography: Useful Technique for Predicting Malignant Potential of Gastrointestinal Stromal Tumors

The malignant potential of gastrointestinal stromal tumors (GISTs) is difficult to diagnose before surgery because the diagnoses are based on tumor diameter and mitotic index. The progression of small GISTs is always observed because they do not seem to have malignant potential. ¹⁸F-Fluorodeoxyglucose (FDG)-positron emission tomography (PET) is a useful technique for assessing tumor activity. The objective of this study was to determine if FDG-PET is useful for predicting the malignant potential of gastric GISTs. Ten patients diagnosed with gastric GISTs participated. FDG-PET was performed on all of them before tumor resection. A whole-body image was initiated 40 minutes after the injection of 275 to 370 MBq FDG. FDG uptake was assessed by a standardized uptake value. All tumors had FDG uptake. There was a significant correlation between the FDG uptake and both the Ki67 index and the mitotic index but not the tumor diameter. The FDG uptake and malignant potential of gastric GISTs had a significant correlation. FDG-PET may be of considerable value for predicting the malignant potential of gastric GISTs before surgery. A gastric GIST with a high FDG uptake should be regarded as having malignant potential.     

Positron Emission Tomography in Clinical Islet Transplantation

The fate of islets in clinical transplantation is unclear. To elude on this positron emission tomography combined with computed tomography (PET/CT) was performed for 60 min during islet transplantation in five patients receiving six transplants. A fraction of the islets (23%) were labeled with 18F‐fluorodeoxyglucose ([¹⁸F]FDG) and carefully mixed with unlabeled islets just prior to intraportal transplantation. The peak radioactivity concentration in the liver was found at 19 min after start of islet infusion and corresponded to only 75% of what was expected, indicating that islets are lost during the transplantation procedure. No accumulation of radioactivity was found in the lungs. A nonphysiological peak of C‐peptide was found in plasma during and immediately after transplantation in all subjects. Distribution in the liver was heterogeneous with wide variations in location and concentration. Islets found in areas with concentrations of >400 IEQ/cc liver tissue varied between 1% and 32% of the graft in different subjects. No side effects attributed to the PET/CT procedure were found. Clinical outcome in all patients was comparable to that previously observed indicating that the [¹⁸F]FDG labeling procedure did not harm the islets. The technique has potential to be used to assess approaches to enhance islet survival and engraftment in clinical transplantation.     

Clinical Significance of 18F-fluorodeoxyglucose Positron Emission Tomography in Superficial Esophageal Squamous Cell Carcinoma

Purpose

To assess the clinical usefulness and significance of ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) in superficial esophageal squamous cell carcinoma (ESCC).

Methods

We examined FDG-PET for 80 consecutive patients with superficial ESCC without neoadjuvant treatment. Fifty-seven patients underwent radical esophagectomy, and 23 patients received endoscopic resection. The FDG uptake index was evaluated with clinicopathological findings, and glucose transporter 1 (Glut-1) expression in primary tumors was examined immunohistochemically.

Results

The FDG uptake in primary tumors correlated with histology, depth of tumor invasion, lymph node metastasis, lymphatic invasion, vascular invasion, and Glut-1 expression. All patients with more than 4.4 maximum standardized uptake value (SUV_max) had deeper invasion of submucosa. Among 16 patients with lymph node metastasis, only two were found to have lymph node metastasis. FDG uptake, depth of tumor invasion, lymph node metastasis, and histology were found to be prognostic factors, and histology was an independent prognostic factor. In FDG uptake–positive patients, depth of tumor invasion and histology were prognostic factors.

Conclusions

FDG-PET is useful for diagnosing tumors with deeper invasion of submucosa and is helpful in making decisions regarding endoscopic treatment for superficial ESCC. Patients with FDG uptake–positive disease, deeper invasion of submucosa, poorly differentiated tumor, and poor prognosis should receive multimodal treatment.     

18F-脱氧葡萄糖正电子发射体层显像在食管癌患者中的应用

目的探讨^18F-脱氧葡萄糖正电子发射体层显像（^18F-FDG—PET）检查在食管癌患者诊断、治疗中的应用价值。方法1999年10月～2005年12月，对52例食管癌患者行全身^18F-FDG—PET检查，其中15例在检查前未经任何治疗，37例为综合治疗后复查。采用目测法结合半定量分析法判读^18F-FDG—PET检查结果，并与病理检查和随访结果进行对比。结果在15例行^18F-FDG—PET检查前未经任何治疗的食管癌患者中，11例患者（T2～T4）原发肿瘤显影，4例T1原发肿瘤未显影；^18F-FDG—PET检查定性诊断的灵敏度为73．3％（11／15）。8例手术治疗的患者切除纵隔和腹腔直径〉1cm的淋巴结16处，术前6处经^18F-FDG—PET检查定性为恶性，其中5处为转移淋巴结，1处为淋巴结结核；7例患者经^18F-FDG—PET检查发现有远处器官转移，不适合手术治疗。37例经综合治疗后患者复查^18F-FDG—PET，发现34例有肿瘤复发和／或转移。结论^18F-FDG—PET检查对食管癌原发肿瘤和局部淋巴结转移的定性诊断价值有限，但对发现远处器官转移和判断治疗效果有较大的帮助，^18F-FDG—PET检查需结合其他辅助检查才能发挥其优势。     

Efficacy of Preoperative Combined 18-Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography for Assessing Primary Rectal Cancer Response to Neoadjuvant Therapy

Purpose Efficacy of F-18 fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) for determining neoadjuvant therapy response in rectal cancer is not well established. We sought to evaluate serial FDG-PET/CT for assessing tumor down-staging, percentage residual tumor, and complete response or microscopic disease with rectal cancer neoadjuvant therapy. Methods Patients with rectal cancer undergoing neoadjuvant therapy, definitive surgical resection, and FDG-PET/CT before and 4–6 weeks after neoadjuvant treatment were included. Tumors were evaluated pretreatment and on final pathology for size and stage. FDG-PET/CT parameters assessed were visual response score (VRS), standardized uptake value (SUV), PET-derived tumor volume (PETvol), CT-derived tumor volume (CTvol), and total lesion glycolysis (δTLG). Results Twenty-one rectal cancer patients over 3 years underwent neoadjuvant treatment, serial FDG-PET/CT, and resection. Complete response or microscopic disease (n = 7, 33%) was associated with higher ΔCTvol (AUC = 0.82, p = 0.004) and ΔSUV (AUC = 0.79, p = 0.01). Tumor down-staging (n = 14, 67%) was associated with greater ΔPETvol (AUC = 0.82, p < 0.001) and ΔSUV (AUC = 0.82, p < 0.001). Pathologic lymph node disease (n = 7, 33%) correlated with ΔCTvol (AUC = 0.75, p = 0.03) and ΔPETvol (AUC = 0.70, p = 0.08). Conclusion FDG-PET/CT parameters were best for assessing tumor down-staging and percentage of residual tumor after neoadjuvant treatment of rectal cancer and can potentially assist in treatment planning. This work was presented in the plenary session of the 47th Annual Meeting of the Society for Surgery of the Alimentary Tract at the Digestive Disease Week in Los Angeles, CA on 24 May 2006.     

Preoperative Evaluation of Pancreatic Masses with Positron Emission Tomography Using 18F-fluorodeoxyglucose: Diagnostic Limitations

Identification of pancreatic cancer in patients presenting with an enlarged pancreatic mass is a major diagnostic problem. Positron emission tomography (PET) using the radiolabeled glucose analogue ¹⁸F-fluorodeoxyglucose (FDG) has been suggested to provide excellent accuracy for noninvasive determination of suspicious pancreatic masses. We conducted a prospective study to verify these results. Forty-two patients admitted for pancreatic surgery underwent PET scanning. Image analysis was based on visual film evaluation and quantification of regional tracer uptake. PET imaging was visually analyzed by three observers blinded for the results of other diagnostic tests; they qualitatively graded the scans using a five-point scale (I = low to V = high) for the presence and intensity of focal FDG uptake. Diagnosis was proven by histology (n= 38) or follow-up (n= 4). Furthermore, the results of PET were compared with helical computed tomography (CT) and conventional ultrasonography (US), done during the routine diagnostic workup before pancreatic cancer surgery. Regarding only the results with scores of IV and V as positive for representing definite malignancy yielded a sensitivity of 71% and a specificity of 64% for film reading. Quantification of regional tracer uptake contributed no significant diagnostic advantage for differentiation between benign and malignant tumors. Helical CT revealed a sensitivity of 74% and a specificity of 45.5% and abdominal US 56% and 50%, respectively. We concluded that PET imaging provides only fair diagnostic accuracy (69%) for characterizing enlarged pancreatic masses. PET does not allow exclusion of malignant tumors. In doubtful cases, the method must be combined with other imaging modalities, such as helical CT. The results indicate that the number of invasive procedures is not significantly reduced by PET imaging.     

Evaluation of 18F-2-deoxy-2-fluoro-<Emphasis Type="SmallCaps">d</Emphasis>-glucose Positron Emission Tomography for Gastric Cancer

Positron emission tomography (PET) with ¹⁸F-2-deoxy-2-fluoro-d-glucose (FDG) has been investigated as a means of detecting certain primary tumors and their metastatic disease in recent years. The aim of this study was to compare the performance of FDG-PET and operative assessment with formal pathologic staging. Altogether, 85 patients had undergone surgical treatment for gastric cancer with curative intent, with FDG-PET preoperatively. The results using FDG-PET were compared with those using computed tomography (CT); they were also correlated with the pathologic findings. For quantitative analysis, the regional tumor uptake was measured by the standard uptake value (SUV) using a region of interest technique. Using FDG-PET, the primary tumor was visualized in 75.2% of patients. A comparison of the FDG uptake and the clinicopathologic findings showed that there was a significant association between FDG uptake and the depth of invasion, the size of the tumor, and lymph node metastasis. FDG-PET scans had less accuracy for diagnosing locoregional lymph nodes than CT because of a significant lack of sensitivity (23.3% vs. 65.0%). The survival rate for patients with high FDG uptake (SUV > 4) was significantly lower than that for those with low FDG uptake (SUV < 4) (p < 0.05). FDG-PET was successful in detecting the primary gastric cancer lesion but not for finding early-stage gastric cancers. Detection of nodal metastasis also was not possible by FDG-PET. However, FDG-PET appears to provide important additional information concerning the aggressiveness of the tumor and the prognosis in patients with gastric cancer.