A prospective diagnostic accuracy study of 18F-fluorodeoxyglucose positron emission tomography/computed tomography, multidetector row computed tomography, and magnetic resonance imaging in primary diagnosis and staging of pancreatic cancer. Ann Surg. 2009;250:957-963. [PMID: 19687736 DOI: 10.1097/sla.0b013e3181b2fafa]

Impact of F18-fluorodeoxyglycose positron emission tomography/computed tomography on the management of resectable pancreatic tumours

BACKGROUND

Positron emission tomography/computed tomography (PET/CT) using F18-fluorodeoxyglucose has been shown to be valuable in the management of malignant disease. The aim of this study is to investigate the impact of this technique on the management of patients with resectable pancreatic tumours.

METHODS

Thirty-six patients with 37 potentially resectable pancreatic tumours on diagnostic CT imaging underwent PET/CT scans. Operative findings, histological reports and/or clinical follow-up served as standard of reference. The impact of PET/CT on patient management was estimated by calculating the percentage of patients whose treatment plan was altered due to PET/CT.

RESULTS

Pancreatic adenocarcinoma was diagnosed in 30 patients, neuroendocrine tumours in 3, mass-forming pancreatitis in 3 and serous cystadenoma in 1. The median standard uptake (max) value was 5.0 (range 2.2-12.0). Sensitivity and specificity of detecting extrapancreatic metastatic disease were 73% and 100%, respectively. Three occult liver metastases were detected at laparotomy following negative PET/CT. PET/CT findings influenced the management of 8 (22%) patients - 3 with liver metastases, 3 with bone metastases, 1 with lymph node metastases and 1 by identifying the benign appearance of the pancreatic tumour.

CONCLUSION

PET/CT achieves a significant diagnostic impact in detecting extrapancreatic metastatic disease. F18-fluorodeoxyglucose PET/CT appears to be useful in assessing suspicious pancreatic masses.

MR imaging versus PET/CT for evaluation of pancreatic lesions

PURPOSE

To retrospectively determine the diagnostic accuracy of magnetic resonance imaging (MRI) and combined positron emission tomography/computed tomography (PET/CT) in the differential diagnosis of benign and malignant pancreatic lesions.

MATERIALS AND METHODS

Twenty-seven patients (15 women/12 men, mean age 56.5 years) with MR imaging and PET/CT studies performed to differentiate benign and malignant pancreatic lesions were identified between October 2008 and October 2010. Both MR and PET/CT data sets were retrospectively and blindly evaluated by two independent readers (4 readers total) with different degrees of experience, using a visual five-point score system. The results were correlated with final diagnosis obtained by histopathology.

RESULTS

17 patients had malignant diseases and 10 patients had benign diseases. Depending on the observer, the sensitivity, specificity, positive predictive value and negative predictive value of MRI varied between 88-94%, 50-80%, 75-89% and 71-89% respectively. Sensitivities, specificities, positive predictive values and negative predictive values of PET/CT were 73%, 56%, 73% and 56% respectively. The diagnostic accuracy of MR for the differential diagnosis of pancreatic lesions was 74-89%, compared with 67% for PET/CT. The weighted Cohen's kappa coefficient was 0.47 at MR and 0.53 at PET/CT.

CONCLUSION

MRI achieved higher sensitivity and specificity in the differential diagnosis of pancreatic lesions.

CA19-9 as a Potential Target for Radiolabeled Antibody-Based Positron Emission Tomography of Pancreas Cancer

Introduction. Sensitive and specific imaging of pancreas cancer are necessary for accurate diagnosis, staging, and treatment. The vast majority of pancreas cancers express the carbohydrate tumor antigen CA19-9. The goal of this study was to determine the potential to target CA19-9 with a radiolabeled anti-CA19-9 antibody for imaging pancreas cancer. Methods. CA19-9 was quantified using flow cytometry on human pancreas cancer cell lines. An intact murine anti-CA19-9 monoclonal antibody was labeled with a positron emitting radionuclide (Iodine-124) and injected into mice harboring antigen positive and negative xenografts. MicroPET/CT were performed at successive time intervals (72 hours, 96 hours, 120 hours) after injection. Radioactivity was measured in blood and tumor to provide objective confirmation of the images. Results. Antigen expression by flow cytometry revealed approximately 1.3 × 10⁶ CA19-9 antigens for the positive cell line and no expression in the negative cell line. Pancreas xenograft imaging with Iodine-124-labeled anti-CA19-9 mAb demonstrated an average tumor to blood ratio of 5 and positive to negative tumor ratio of 20. Conclusion. We show in vivo targeting of our antigen positive xenograft with a radiolabeled anti-CA19-9 antibody. These data demonstrate the potential to achieve anti-CA19-9 antibody based positron emission tomography of pancreas cancer.

Current treatment options for pancreatic carcinoma

Pancreas cancer is a significant cause of cancer mortality; therefore, the development of early diagnostic strategies and effective treatment is essential. Improvements in imaging technology, as well as use of biomarkers such as CA 19-9, are changing the way that pancreas cancer is diagnosed and staged. Although progress in treatment for pancreas cancer has been incremental, development of combination therapies involving both chemotherapeutic and biologic agents is ongoing. This article reviews current strategies in the diagnosis and treatment of resectable and advanced pancreas cancer.

Pancreato-biliary malignancy diagnosed by endoscopic ultrasonography in absence of a mass lesion on transabdominal imaging: prevalence and predictors

BACKGROUND AND AIMS

Pancreatic adenocarcinoma is the fourth leading cause of cancer-related death in the United States. Pancreatic cancer is diagnosed in some patients by endoscopic ultrasonography (EUS) even in the absence of an obvious mass lesion on transabdominal imaging studies. The purpose of this study was to estimate the prevalence of PBM on EUS-FNA in patients with no obvious mass on transabdominal imaging and identify possible predictors of PBM in this cohort of patients.

METHODS

Three hundred and twenty-six patients (219 female; mean age: 57) with no obvious neoplastic lesion on trans-abdominal imaging underwent EUS. Demographic data, indication of EUS, history of weight loss, smoking, alcohol use, diabetes, cholecystectomy status, CT and USG findings, and liver function tests (LFTs) were reviewed.

RESULTS

Thirty patients (9%) were diagnosed with a PBM by EUS-FNA (27 pancreatic adenocarcinoma, three ampullary adenocarcinoma). The mean age of patients diagnosed with PBM was significantly (P < 0.01) higher than controls. The mean size of the tumor was 2.8 cm (range: 0.9-7 cm). Male gender, presence of jaundice, abnormal LFTs, weight loss, and nonspecific trans-abdominal imaging results such as dilated common bile duct (CBD), and abnormal appearing pancreas predicted the presence (P < 0.05) of PBM, whereas patients with previous cholecystectomy and abdominal pain were less likely to have this diagnosis.

CONCLUSIONS

Normal trans-abdominal imaging does not completely exclude the presence of PBM. Nonspecific pancreatic abnormalities and CBD dilation on trans-abdominal imaging, with jaundice, abnormal LFTs, weight loss, and lack of abdominal pain are predictors of PBM.

Imaging evaluation of therapeutic response in patients with pancreatic cancer: recent advances

Chemoradiotherapy is the primary choice of non-surgical treatment of advanced pancreatic cancer, and diagnostic imaging plays an important role in objectively assessing early therapeutic response. This article systematically reviews the criteria for evaluation of therapeutic response in solid tumors and their application in pancreatic cancer, highlighting some key contents in imaging evaluation of therapeutic response in patients with pancreatic cancer.

Anti-CA19-9 diabody as a PET imaging probe for pancreas cancer

BACKGROUND

Intact antibodies are poor imaging agents due to a long serum half-life (10-20 d) preventing adequate contrast between the tumor and surrounding blood. Smaller engineered antibody fragments overcome this problem by exhibiting shorter serum half-lives (4-20 h).The diabody (55 kDa) is the smallest antibody fragment, which retains the bivalency of the intact antibody. Our goal was to develop and characterize the anti-CA19-9 diabody fragment and determine its ability to provide antigen specific imaging of pancreas cancer.

METHODS

The diabody DNA construct was created by isolation of the variable region genes of the intact anti-CA19-9 antibody. Diabody expression was carried out in NS0 cells and purified using HPLC from supernatant. Specific antigen binding was confirmed with flow cytometry and immunofluorescence. Radiolabeled diabody was injected into mice harboring an antigen positive xenograft (BxPC3 or Capan-2) and a negative xenograft (MiaPaca-2). MicroCT and MicroPET were performed at successive time intervals after injection. Radioactivity was measured in blood and tumor to provide objective confirmation of the microPET images.

RESULTS

Immunofluorescence and flow cytometry showed specific binding of the anti-CA19-9 diabody. Pancreas xenograft imaging of BxPC3/MiaPaca-2 and Capan-2/MiaPaca-2 models with the anti-CA19-9 diabody demonstrated an average tumor:blood ratio of 5.0 and 2.0, respectively, and an average positive:negative tumor ratio of 11 and 6, respectively. With respect to the tumor:blood ratio, these data indicate five times and two times more radioactivity in the tumor than in the blood yielding adequate contrast between tumor tissue and background (i.e., blood) to create the representative microPET images.

CONCLUSIONS

We successfully engineered a functional diabody against CA19-9, a tumor antigen present on the vast majority of pancreas cancers. Additionally, we demonstrate high contrast antigen specific microPET imaging of pancreas cancer in xenograft models.

Value of contrast-enhanced 18F-fluorodeoxyglucose positron emission tomography/computed tomography in detection and presurgical assessment of pancreatic cancer: a prospective study

BACKGROUND AND AIM

Positron Emission Tomography (PET) using (18)F-fluorodeoxyglucose (FDG) associated with computed tomography (CT) is increasingly used for the detection and the staging of pancreatic cancer, but data regarding its clinical added value in pre-surgical planning is still lacking. The aim of this study is to investigate the performance of FDG PET associated with contrast-enhanced CT in detection of pancreatic cancer.

METHODS

We prospectively evaluated FDG PET/CT studies obtained in patients with suspicion of operable pancreatic cancer between May 2006 and January 2008. Staging was conducted according to a standardized protocol, and findings were confirmed in all patients by surgical resection or biopsy examination.

RESULTS

Forty-five patients with a median age of 69 (range 22-82) were included in this study. Thirty-six had malignant tumors and nine had benign lesions (20%). The sensitivity of enhanced versus unenhanced PET/CT in the detection of pancreatic cancer was 96% versus 72% (P=0.076), the specificity 66.6% versus 33.3% (P=0.52), the positive predictive value 92.3% versus 80% (P=0.3), the negative predictive value 80% versus 25% (P=0.2), and the accuracy 90.3% versus 64% (P=0.085).

CONCLUSIONS

Our preliminary data obtained in a limited number of patients shows that contrast-enhanced FDG PET/CT offers good sensitivity in the detection and assessment of pancreatic cancer, but at the price of a relatively low specificity. Enhanced PET/CT seems to be superior to unenhanced PET/CT. Further larger prospective studies are needed to establish its value for pre-surgical diagnosis and staging in pancreatic cancer.

Gadobenate dimeglumine-enhanced 3.0-T MR imaging versus multiphasic 64-detector row CT: prospective evaluation in patients suspected of having pancreatic cancer

PURPOSE

To compare the diagnostic performance (detection, local staging) of multiphasic 64-detector row computed tomography (CT) with that of gadobenate dimeglumine-enhanced 3.0-T magnetic resonance (MR) imaging in patients suspected of having pancreatic cancer.

MATERIALS AND METHODS

The institutional review board approved this prospective study, and all patients provided written informed consent. Multidetector CT and MR imaging were performed in 89 patients (48 women aged 46-89 years [mean, 65.6 years] and 41 men aged 46-86 years [mean, 65.3 years]) suspected of having pancreatic cancer on the basis of findings from clinical examination or previous imaging studies. Two readers independently assessed the images to characterize lesions and determine the presence of focal masses, vascular invasion, distant metastases, and resectability. Findings from surgery, biopsy, endosonography, or follow-up imaging were used as the standard of reference. Logistic regression, the McNemar test, and κ values were used for statistical analysis.

RESULTS

Focal pancreatic masses were present in 63 patients; 43 patients had adenocarcinoma. For reader 1, the sensitivities and specificities in the detection of pancreatic adenocarcinoma were 98% (42 of 43 patients) and 96% (44 of 46 patients), respectively, for CT and 98% (42 of 43 patients) and 96% (44 of 46 patients) for MR imaging. For reader 2, the sensitivities and specificities were 93% (40 of 43 patients) and 96% (44 of 46 patients), respectively, for CT and 95% (41 of 43 patients) and 96% (44 of 46 patients) for MR imaging. Vessel infiltration was determined in 22 patients who underwent surgery, and reader 1 obtained sensitivities and specificities of 90% (nine of 10 vessels) and 98% (119 of 122 vessels), respectively, for CT and 80% (eight of 10 vessels) and 96% (117 of 122 vessels) for MR imaging; for reader 2, those values were 70% (seven of 10 vessels) and 98% (120 of 122 vessels) for CT and 50% (five of 10 vessels) and 98% (120 of 122 vessels) for MR imaging. Both readers correctly assessed resectability in 87% (13 of 15 patients) of cases with CT and 93% (14 of 15 patients) of cases with MR imaging. Nonresectability was assessed correctly with CT in 75% (six of eight patients) of cases by reader 1 and 63% (five of eight patients) of cases by reader 2; nonresectability was correctly assessed with MR imaging in 75% (six of eight patients) of cases by reader 1 and 50% (four of eight patients) of cases by reader 2. None of the differences between modalities and readers were statistically significant (P > .05).

CONCLUSION

Both CT and MR imaging are equally suited for detecting and staging pancreatic cancer.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101189/-/DC1.

Pancreatic neoplasia: a practical cross-sectional imaging primer for the nonradiologist

PURPOSE

The purpose of this article is to provide a practical review of basic pancreatic imaging protocols and key cross-sectional imaging findings of the more common pancreatic neoplasms.

METHODS

We performed a literature search and reviewed numerous cases archived in the radiology department of a large university hospital to find examples which illustrate the key cross-sectional imaging findings of pancreatic neoplasms.

RESULTS

We reviewed the literature and provided several practical examples of common cross-sectional imaging findings in patients with pancreatic neoplasms.

CONCLUSIONS

Cross-sectional imaging plays a pivotal role in the evaluation of pancreatic neoplasms and allows proper triage of patients for conservative, medical or surgical management due to its ability to reliably detect and characterize pancreatic lesions, determine involvement of local structures, and assess metastatic disease. Familiarity with the key imaging findings will allow the clinician to better implement imaging data into daily practice.

Role of staging laparoscopy in peri-pancreatic and hepatobiliary malignancy

Even after extensive preoperative assessment, staging laparoscopy may allow avoidance of non-therapeutic laparotomy in patients with radiographically occult metastatic or locally unresectable disease. Staging laparoscopy is associated with decreased postoperative pain, a shorter hospital stay and a higher likelihood of receiving systemic therapy compared to laparotomy but its yield has decreased with improvements in imaging techniques. Current uses of staging laparoscopy include the following: (1) In the staging of pancreatic adenocarcinoma, laparoscopic staging allows for the identification of sub-radiographic metastatic disease in locally advanced cancer in approximately 30% of patients and, in radiographically resectable cancer, may identify metastatic disease in 10%-15% of cases; (2) In colorectal liver metastases, selective use of laparoscopic staging in patients with a clinical risk score of over 2 identifies unresectable disease in approximately 20% of patients; (3) In hepatocellular carcinoma, laparoscopic staging could be selectively used in high-risk patients such as those with clinically apparent liver cirrhosis and in patients with major vascular invasion or bilobar tumors; and (4) In biliary tract malignancy, staging laparoscopy may be used in all patients with potentially resectable primary gallbladder cancer and in selected patients with T2/T3 hilar cholangiocarcinoma. Because of the decreasing yield of SL secondary to improvements in imaging techniques, staging laparoscopy should be used selectively for patients with pancreatic and hepatobiliary malignancy to avoid unnecessary non-therapeutic laparotomy and to improve resource utilization. Each individual surgeon should apply his or her threshold as to whether staging laparoscopy is indicated according to the quality of preoperative imaging studies and the availability of resources at their own institution.

Ampullary cancer

PURPOSE OF REVIEW

This manuscript reviews the recent literature on ampullary cancer, including new staging definitions, histological characteristics and treatment options.

RECENT FINDINGS

Recent publications emphasize the importance of the histological differentiation (intestinal vs. pancreatobiliary), which is one of the most important prognostic factors for ampullary cancer. These histological subtypes can be differentiated by immunohistochemistry: while positivity for mucin-2 (MUC2) and caudal homeobox gene transcription factor-2 (CDX2) excludes the pancreatobiliary subtype, positivity for MUC1 and cytokeratin-17 (CK17) excludes the intestinal subtype. Also, different mechanisms of cancer development have been described, which might be related to the type of differentiation. Due to the very low risk of lymphatic spread, local resections appear sufficient for well differentiated T1 cancer smaller than 1 cm, whereas larger, less differentiated or more invasive cancer requires a radical resection. As cancer with intestinal differentiation shares a similar biology with colon cancer, and the pancreatobiliary differentiation is close to ductal adenocarcinoma of the pancreas, adjuvant chemotherapy should probably be given according to colon cancer (intestinal) and pancreatic cancer (pancreatobiliary), respectively. However, randomized trials are lacking.

SUMMARY

The recent research suggests that the histological differentiation of periampullary cancer is more important than the anatomical location (ampulla). Future studies are required to take this emerging issue into account.