Diagnostic imaging for pancreatic cancer: computed tomography, magnetic resonance imaging, and positron emission tomography

Deep Learning for Medical Image-Based Cancer Diagnosis

(1) Background: The application of deep learning technology to realize cancer diagnosis based on medical images is one of the research hotspots in the field of artificial intelligence and computer vision. Due to the rapid development of deep learning methods, cancer diagnosis requires very high accuracy and timeliness as well as the inherent particularity and complexity of medical imaging. A comprehensive review of relevant studies is necessary to help readers better understand the current research status and ideas. (2) Methods: Five radiological images, including X-ray, ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), positron emission computed tomography (PET), and histopathological images, are reviewed in this paper. The basic architecture of deep learning and classical pretrained models are comprehensively reviewed. In particular, advanced neural networks emerging in recent years, including transfer learning, ensemble learning (EL), graph neural network, and vision transformer (ViT), are introduced. Five overfitting prevention methods are summarized: batch normalization, dropout, weight initialization, and data augmentation. The application of deep learning technology in medical image-based cancer analysis is sorted out. (3) Results: Deep learning has achieved great success in medical image-based cancer diagnosis, showing good results in image classification, image reconstruction, image detection, image segmentation, image registration, and image synthesis. However, the lack of high-quality labeled datasets limits the role of deep learning and faces challenges in rare cancer diagnosis, multi-modal image fusion, model explainability, and generalization. (4) Conclusions: There is a need for more public standard databases for cancer. The pre-training model based on deep neural networks has the potential to be improved, and special attention should be paid to the research of multimodal data fusion and supervised paradigm. Technologies such as ViT, ensemble learning, and few-shot learning will bring surprises to cancer diagnosis based on medical images.

T2-weighted MRI and reduced-FOV diffusion-weighted imaging of the human pancreas at 5 T: A comparison study with 3 T

PURPOSE

The purpose of this study was to explore the feasibility of pancreatic imaging at 5 T and evaluate the practical improvement of T2-weighted MRI and diffusion-weighted imaging (DWI) at 5 T as compared with 3 T.

METHODS

Eighteen healthy subjects were recruited for this pilot study. MRI examinations were performed using 3 and 5 T scanners. MRI sequences included T2-weighted fast spin-echo and DWI with reduced field-of-view. Subjective image analysis using a four-point Likert scale was performed by two experienced radiologists. The SNR, contrast ratio, and apparent diffusion coefficient (ADC) were measured in the pancreatic head, body, and tail. The coefficient of variation (CV) of the ADC was calculated. A series of paired Wilcoxon tests were used to compare the subjective image quality, mean ADC value, and CV of ADC between the 3 and 5 T measurements. p <0.05 was considered statistically significant.

RESULTS

For T2-weighted images, there were no significant differences in image quality ratings between 3 and 5 T. On DWI images (b = 0 and 800 s/mm² ), the image quality ratings were significantly higher at 5 T than at 3 T. The SNRs of both T2-weighted and DWI images were significantly higher at 5 T. There was no significant difference in the mean ADC values and CV of ADC between 3 and 5 T.

CONCLUSION

This initial study proved that 5 T MRI can be used to acquire pancreatic images with higher SNR and sufficient image quality compared to 3 T MRI.

The Role of Endoscopic Ultrasonography in the Diagnosis and Staging of Pancreatic Cancer

Pancreatic cancer is the fourth leading cause of cancer-related death and the second gastrointestinal cancer-related death in the United States. Early detection and accurate diagnosis and staging of pancreatic cancer are paramount in guiding treatment plans, as surgical resection can provide the only potential cure for this disease. The overall prognosis of pancreatic cancer is poor even in patients with resectable disease. The 5-year survival after surgical resection is ~10% in node-positive disease compared to ~30% in node-negative disease. The advancement of imaging studies and the multidisciplinary approach involving radiologists, gastroenterologists, advanced endoscopists, medical, radiation, and surgical oncologists have a major impact on the management of pancreatic cancer. Endoscopic ultrasonography is essential in the diagnosis by obtaining tissue (FNA or FNB) and in the loco-regional staging of the disease. The advancement in EUS techniques has made this modality a critical adjunct in the management process of pancreatic cancer. In this review article, we provide an overall description of the role of endoscopic ultrasonography in the diagnosis and staging of pancreatic cancer.

MRI-Based Upper Abdominal Organs-at-Risk Atlas for Radiation Oncology

PURPOSE

The purpose of our study was to provide a guide for identification and contouring of upper abdominal organs-at-risk (OARs) in the setting of online magnetic resonance imaging (MRI)-guided radiation treatment planning and delivery.

METHODS AND MATERIALS

After a needs assessment survey, it was determined that an upper abdominal MRI-based atlas of normal OARs would be of benefit to radiation oncologists and radiation therapists. An anonymized diagnostic 1.5T MRI from a patient with typical upper abdominal anatomy was used for atlas development. Two MRI sequences were selected for contouring, a T1-weighted gadoxetic acid contrast-enhanced MRI acquired in the hepatobiliary phase and axial fast imaging with balanced steady-state precession. Two additional clinical MRI sequences from commercial online MRI-guided radiation therapy systems were selected for contouring and were included in the final atlas. Contours from each data set were completed and reviewed by radiation oncologists, along with a radiologist who specializes in upper abdominal imaging, to generate a consensus upper abdominal MRI-based OAR atlas.

RESULTS

A normal OAR atlas was developed, including recommendations for contouring. The atlas and contouring guidance are described, and high-resolution MRI images and contours are displayed. OARs, such as the bile duct and biliary tree, which may be better seen on MRI than on computed tomography, are highlighted. The full DICOM/DICOM-RT MRI images from both the diagnostic and clinical online MRI-guided radiation therapy systems data sets have been made freely available, for educational purposes, at econtour.org.

CONCLUSIONS

This MRI contouring atlas for upper abdominal OARs should provide a useful reference for contouring and education. Its routine use may help to improve uniformity in contouring in radiation oncology planning and OAR dose calculation. Full DICOM/DICOM-RT images are available online and provide a valuable educational resource for upper abdominal MRI-based radiation therapy planning and delivery.

Detection of Marker miRNAs, Associated with Prostate Cancer, in Plasma Using SOI-NW Biosensor in Direct and Inversion Modes

Information about the characteristics of measuring chips according to their storage conditions is of great importance for clinical diagnosis. In our present work, we have studied the capability of chips to detect nanowire biosensors when they are either freshly prepared or have been stored for either one or two years in a clean room. Potential to detect DNA oligonucleotides (oDNAs)-synthetic analogues of microRNAs (miRNAs) 198 and 429 that are associated with the development of prostate cancer (PCa)-in buffer solution was demonstrated using a nanowire biosensor based on silicon-on-insulator structures (SOI-NW biosensor). To provide biospecific detection, nanowire surfaces were sensitized with oligonucleotide probes (oDNA probes) complimentary to the known sequences of miRNA 183 and 484. In this study it is demonstrated that freshly prepared SOI-NW biosensor chips with n-type conductance and immobilized oDNA probes exhibit responses to the addition of complimentary oDNAs in buffer, leading to decreases in chips' conductance at a concentration of 3.3 × 10-16 M. The influence of storage time on the characteristics of SOI-NW biosensor chips is also studied herein. It is shown that a two-year storage of the chips leads to significant changes in their characteristics, resulting in "inverse" sensitivity toward negatively charged oDNA probes (i.e., through an increase in chips' conductance). It is concluded that the surface layer makes the main contribution to conductance of the biosensor chip. Our results indicate that the detection of target nucleic acid molecules can be carried out with high sensitivity using sensor chips after long-term storage, but that changes in their surface properties, which lead to inversed detection signals, must be taken into account. Examples of the applications of such chips for the detection of cancer-associated microRNAs in plasma samples of patients with diagnosed prostate cancer are given. The results obtained herein are useful for the development of highly sensitive nanowire-based diagnostic systems for the revelation of (prostate) cancer-associated microRNAs in human plasma.

Extradomain-B Fibronectin-Targeted Dextran-Based Chemical Exchange Saturation Transfer Magnetic Resonance Imaging Probe for Detecting Pancreatic Cancer

A dextran-peptide conjugate was developed for magnetic resonance (MR) molecular imaging of pancreatic ductal adenocarcinoma (PDAC) through its overexpressed microenvironment biomarker, extradomain-B fibronectin (EDB-FN). This new agent consists of diamagnetic and biocompatible dextran and a targeting peptide. Dextrans can be directly detected by chemical exchange saturation transfer magnetic resonance imaging (CEST MRI) without the need for radionuclide or metallic labeling. In addition, large molecular weight dextran, dextran 10 (MW ∼ 10 kDa), provides an approximately 50 times higher sensitivity per molecule than a single glucose unit. The potential of this highly biocompatible diamagnetic probe is demonstrated in a murine syngeneic allograft PDAC tumor model. The biocompatibility and sensitivity of this new agent clearly show potential for a path to clinical translation.

Magnetic resonance imaging (MRI) compared with computed tomography (CT) for interobserver agreement of gross tumor volume delineation in pancreatic cancer: a multi-institutional contouring study on behalf of the AIRO group for gastrointestinal cancers

BACKGROUND

Due to the high soft tissue resolution, magnetic resonance imaging (MRI) could improve the accuracy of pancreatic tumor delineation in radiation treatment planning. A multi-institutional study was proposed to evaluate the impact of MRI on inter-observer agreement in gross tumor volume (GTV) and duodenum delineation for pancreatic cancer compared with computer tomography (CT).

MATERIAL AND METHODS

Two clinical cases of borderline resectable (Case 1) and unresectable (Case 2) pancreatic cancer were selected. In two sequential steps, diagnostic contrast-enhanced CT scan and MRI sequences were sent to the participating centers. CT-GTVs were contoured while blinded to MRI data sets. DICE index was used to evaluate the spatial overlap accuracy.

RESULTS

Thirty-one radiation oncologists from different Institutions submitted the delineated volumes. CT- and MRI-GTV mean volumes were 21.6 ± 9.0 cm³ and 17.2 ± 6.0 cm³, respectively for Case 1, and 31.3 ± 15.6 cm³ and 33.2 ± 20.2 cm³, respectively for Case 2. Resulting MRI-GTV mean volume was significantly smaller than CT-GTV in the borderline resectable case (p < .05). A substantial agreement was shown by the median DICE index for CT- and MRI-GTV resulting as 0.74 (IQR: 0.67-0.75) and 0.61 (IQR: 0.57-0.67) for Case 1; a moderate agreement was instead reported for Case 2: 0.59 (IQR:0.52-0.66) and 0.53 (IQR:0.42-0.62) for CT- and MRI-GTV, respectively.

CONCLUSION

Diagnostic MRI resulted in smaller GTV in borderline resectable case with a substantial agreement between observers, and was comparable to CT scan in interobserver variability, in both cases. The greater variability in the unresectable case underlines the critical issues related to the outlining when vascular structures are more involved. The integration of MRI with contrast-enhancement CT, thanks to its high definition of tumor relationship with neighboring vessels, could offer a greater accuracy of target delineation.

MRI guided stereotactic radiotherapy for locally advanced pancreatic cancer

OBJECTIVE:

We want to explore the safety and technical feasibility of MRI-guided stereotactic radiotherapy for locally advanced pancreatic cancer.

METHODS:

A custom-made abdominal corset was manufactured to reduce breathing induced tumour motion. Delineation of the tumour and organs at risk (OARs) was performed on CT and multiparametric MRI. Tumour motion was quantified with cine MRI. After treatment planning, the static dose distribution was convolved with the cine MRI-based motion trajectory to simulate the delivered dose to the tumour and OARs. Stereotactic body radiation therapy (SBRT) was carried out up to a dose of 24 G in three fractions in 1 week.

RESULTS:

From July 2013 to January 2016, 20 patients were included. Tumours and OARs were clearly visible with contrast-enhanced CT and MRI. After simulation of the delivered dose taking the motion into account, an adequate target coverage was achieved with acceptable dose in the OARs. No Grade3 or higher treatment related toxicity was observed.

CONCLUSION:

MRI-guided SBRT for pancreatic cancer is technical feasible and safe, with no treatment related grade ≥3 toxicity. New strategies are applied, including an individual corset to reduce breathing motion, MRI-based delineation and simulation of motion-integrated dose distributions.

ADVANCES IN KNOWLEDGE:

This article is the first to describe an MRI-integrated workflow in SBRT for locally advanced pancreatic cancer. In addition, it demonstrated that SBRT with an abdominal corset to reduce tumour motion is feasible and safe.

TRIAL REGISTRATION:

This trial was registered at www.clinicaltrials.gov (NCT01898741) on July 9, 2013.

Accessory Spleen Mimicking a Pancreatic Neuroendocrine Tumor

A 60-year-old man underwent computed tomography as part of colorectal cancer follow-up. A hypervascular nodule was found within the pancreatic tail and subsequently proved to be positive on [111In] DTPA-octreotide scan. A neuroendocrine tumor of the pancreas was supposed and a distal pancreatectomy performed. Heterotopic splenic tissue was finally proved by pathological examination. The present case suggests that intrapancreatic accessory spleen be considered in the differential diagnosis of pancreatic lesions positive on [111In] DTPA-octreotide scan.

Primary pancreatic lymphoma: what we need to know

Hodgkin's lymphoma is a group of malignant lymphoid which involve various organs including gastrointestinal tract. Stomach and small intestine are commonly involved more; however, pancreas can be primarily involved as well. The secondary involvement of pancreas caused by Hodgkin's lymphoma is more prevalent than the primarily involvement (1 .25-2.2% vs. <1%). Primary pancreatic lymphomas (PPLs) consist of 1-2% of all lymphoma outside nods. The symptoms and findings of PPL imaging can be akin to that of pancreas adenocarcinoma and differentiating them is difficult without examining the tissue sample. The prognosis and treatment of PPL are different from those of adenocarcinoma and due to the superior prognosis of PPL compared to pancreas adenocarcinoma, the proper diagnosis of the disease is important.

Multiplexed detection of lung cancer biomarkers in patients serum with CMOS-compatible silicon nanowire arrays

In this work, a real-time assay for highly sensitive, label-free, multiplexed electrical detection of lung cancer biomarkers was developed by using silicon nanowire field-effect (SiNW-FET) devices. Highly responsive SiNW arrays were fabricated using a CMOS-compatible anisotropic self-stop etching technique with mass reproducibility and low cost character. The SiNW nanosensor was integrated with PDMS microfluidic device, which allows rapid analyte delivery, makes the analysis to be conducted using exceedingly small samples and enables potential multiplexed detection. The nanowire arrays allowed highly selective and sensitive multiplexed detection of microRNA (miRNA)-126 and CEA. Due to high surface-to-volume ratio that the nanowire dimensions confer, the detection floor of single molecule was achieved. The potential utility in identifying clinical samples for early diagnosis of cancer was demonstrated by analyzing biomarkers in clinical related samples. The developed nanosensor with capability for multiplexed real-time monitoring of biomarkers with high sensitivity and selectivity in clinically relevant samples is highly attractive for diagnosis and treatment of cancer and other diseases.

Recommendations for MRI-based contouring of gross tumor volume and organs at risk for radiation therapy of pancreatic cancer

PURPOSE

Local recurrence is a common and morbid event in patients with unresectable pancreatic adenocarcinoma. A more conformal and targeted radiation dose to the macroscopic tumor in nonmetastatic pancreatic cancer is likely to reduce acute toxicity and improve local control. Optimal soft tissue contrast is required to facilitate delineation of a target and creation of a planning target volume with margin reduction and motion management. Magnetic resonance imaging (MRI) offers considerable advantages in optimizing soft tissue delineation and is an ideal modality for imaging and delineating a gross tumor volume (GTV) within the pancreas, particularly as it relates to conformal radiation planning. Currently, no guidelines have been defined for the delineation of pancreatic tumors for radiation therapy treatment planning. Moreover, abdominal MRI sequences are complex and the anatomy relevant to the radiation oncologist can be challenging. The purpose of this study is to provide recommendations for delineation of GTV and organs at risk (OARs) using MRI and incorporating multiple MRI sequences.

METHODS AND MATERIALS

Five patients with pancreatic cancer and 1 healthy subject were imaged with MRI scans either on 1.5T or on 3T magnets in 2 separate institutes. The GTV and OARs were contoured for all patients in a consensus meeting.

RESULTS

An overview of MRI-based anatomy of the GTV and OARs is provided. Practical contouring instructions for the GTV and the OARs with the aid of MRI were developed and included in these recommendations. In addition, practical suggestions for implementation of MRI in pancreatic radiation treatment planning are provided.

CONCLUSIONS

With this report, we attempt to provide recommendations for MRI-based contouring of pancreatic tumors and OARs. This could lead to better uniformity in defining the GTV and OARs for clinical trials and in radiation therapy treatment planning, with the ultimate goal of improving local control while minimizing morbidity.

Molecular Imaging of Pancreatic Cancer with Antibodies

Development of novel imaging probes for cancer diagnostics remains critical for early detection of disease, yet most imaging agents are hindered by suboptimal tumor accumulation. To overcome these limitations, researchers have adapted antibodies for imaging purposes. As cancerous malignancies express atypical patterns of cell surface proteins in comparison to noncancerous tissues, novel antibody-based imaging agents can be constructed to target individual cancer cells or surrounding vasculature. Using molecular imaging techniques, these agents may be utilized for detection of malignancies and monitoring of therapeutic response. Currently, there are several imaging modalities commonly employed for molecular imaging. These imaging modalities include positron emission tomography (PET), single-photon emission computed tomography (SPECT), magnetic resonance (MR) imaging, optical imaging (fluorescence and bioluminescence), and photoacoustic (PA) imaging. While antibody-based imaging agents may be employed for a broad range of diseases, this review focuses on the molecular imaging of pancreatic cancer, as there are limited resources for imaging and treatment of pancreatic malignancies. Additionally, pancreatic cancer remains the most lethal cancer with an overall 5-year survival rate of approximately 7%, despite significant advances in the imaging and treatment of many other cancers. In this review, we discuss recent advances in molecular imaging of pancreatic cancer using antibody-based imaging agents. This task is accomplished by summarizing the current progress in each type of molecular imaging modality described above. Also, several considerations for designing and synthesizing novel antibody-based imaging agents are discussed. Lastly, the future directions of antibody-based imaging agents are discussed, emphasizing the potential applications for personalized medicine.

Role of magnetic resonance imaging in the detection and characterization of solid pancreatic nodules: An update

Pancreatic ductal adenocarcinoma is the most common malignant tumor of the pancreas. The remaining pancreatic tumors are a diverse group of pancreatic neoplasms that comprises cystic pancreatic neoplasms, endocrine tumors and other uncommon pancreatic tumors. Due to the excellent soft tissue contrast resolution, magnetic resonance imaging (MRI) is frequently able to readily separate cystic from noncystic tumors. Cystic tumors are often easy to diagnose with MRI; however, noncystic non-adenocarcinoma tumors may show a wide spectrum of imaging features, which can potentially mimic ductal adenocarcinoma. MRI is a reliable technique for the characterization of pancreatic lesions. The implementation of novel motion-resistant pulse sequences and respiratory gating techniques, as well as the recognized benefits of MR cholangiopancreatography, make MRI a very accurate examination for the evaluation of pancreatic masses. MRI has the distinctive ability of non-invasive assessment of the pancreatic ducts, pancreatic parenchyma, neighbouring soft tissues, and vascular network in one examination. MRI can identify different characteristics of various solid pancreatic lesions, potentially allowing the differentiation of adenocarcinoma from other benign and malignant entities. In this review we describe the MRI protocols and MRI characteristics of various solid pancreatic lesions. Recognition of these characteristics may establish the right diagnosis or at least narrow the differential diagnosis, thus avoiding unnecessary tests or procedures and permitting better management.

Bile Duct Strictures Caused by Solid Masses: MR in Differential Diagnosis and as a Prognostic Tool to Plan the Endoscopic Treatment

The aim of the study was to assess how realiable is differential diagnosis and prognosis for endoscopic treatment with MR signal characteristics as the qualitative parameter and magnetic resonance cholangiopancreatography (MRCP) images in cases of bile duct obstructions caused by solid masses. Material and Methods. Retrospective study of MR and MRCP images in 80 patients (mean age 58 ys) was conducted. Mean signal intensity ratio (SIR) from planar MR images and MRCP linear measurements were compared between benign and malignant lesions and in groups including the size and number of stents placed during ERCP (< 10 F <) in 51 cases in which ERCP was performed. Results. Significantly higher SIR values were encountered in malignant lesions in T2W images (r = 0,0003) and STIR T2W images (r = 0,0002). Malignant lesions were characterised by longer strictures (r = 0,0071) and greater proximal biliary duct dilatation (r = 0,0024). High significance for predicting ERCP conditions was found with mean SIR in STIR T2W images and stricture length. Conclusion. Probability of malignancy of solid lesions obstructing biliary duct increased with higher SIR in T2W images and with longer strictures. Passing the stricture during ERCP treatment was easier and more probable in cases of shorter strictures caused by lesions with higher SIR in STIR T2W images.

Computed tomography-based diagnostics might be insufficient in the determination of pancreatic cancer unresectability

AIM: To inquire into a question of an overestimation of arterial involvement in patients with pancreatic cancer (PC).

METHODS: Radiology data were compared with the findings from 51 standard, 58 extended and 17 total pancreaticoduodenectomies; 9 distal resections with celiac artery (CA) excision; and 28 palliations for PC. The survival of 11 patients with controversial computed tomography (CT) and endoscopic ultrasound data with regard to arterial invasion, after R0/R1 procedures (false-positive CT results, Group A), was compared to survival after eight R2 resections (false-negative CT results, Group B) and after 12 bypass procedures for locally advanced cancer (true-positive CT results, Group C).

RESULTS: In all of the cases in group A, operative exploration revealed no arterial invasion, which was predicted by CT. The one-year survival in Group A was 88.9%, and the two-year survival was 26.7%, with a median follow-up of 22 mo. One-year survival was not attained in groups B and C, with a significant difference in survival (P_a-b = 0.0029, P_b-c = 0.003).

CONCLUSION: Arterial encasement on CT does not necessarily indicate arterial invasion. Whenever PC is considered unresectable, endoUS should be used. In patients with controversial CT an EUS data for peripancreatic arteries involvement radical resection might be possible, providing survival benefits as compared to R2- resections or palliative surgery.

Label-free electrochemical impedance spectroscopy biosensor for direct detection of cancer cells based on the interaction between carbohydrate and lectin

A novel label-free electrochemical impedance spectroscopy (EIS) biosensor for direct cancer cell detection based on the interaction between carbohydrate and lectin has been developed with good sensitivity and selectivity. In the present work, concanavalin A (Con A), a mannose specific lectin, was immobilized on a gold disk electrode to fabricate the Con A sensor. This sensor was incubated with the cancer cell sample, and the binding of cancer cells with Con A resulted in a change of charge transfer resistance (Rct). EIS measurement was employed to measure the impedance change which reveals the concentration of cancer cells. This method has been successfully applied in human liver cancer cell Bel-7404 for direct and sensitive detection with a detection limit of 234cells/mL. This method could be extended to carry out multi-component diagnosis applications, thus providing enormous potential for applications of cancer monitoring and therapy.

Value of diffusion-weighted imaging for the discrimination of pancreatic lesions: a meta-analysis

OBJECTIVE

We aimed to explore the role of diffusion-weighted imaging (DWI) in the discrimination of pancreatic lesions through meta-analysis.

METHODS

The MEDLINE, EMBASE, Cancerlit, and Cochrane Library databases, from January 2001 to August 2011, were searched for studies evaluating the diagnostic performance of DWI in the discrimination of pancreatic lesions. We determined sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-), and constructed summary receiver operating characteristic curves.

RESULTS

A total of 11 studies with 586 patients, who fulfilled all of the inclusion criteria, were considered for the analysis. No publication bias was found. The pooled sensitivity of DWI was 0.86 [95% (confidence interval (CI), 0.78, 0.91] and the pooled specificity was 0.91 (95% CI, 0.81, 0.96). Overall, LR+ was 9.8 (95% CI, 4.1, 23.3) and LR- was 0.15 (95% CI, 0.09, 0.26). The area under the curve of the summary receiver operating characteristic was 0.94 (95% CI, 0.91-0.96). In subgroup analysis, prospectively designed studies had the highest pooled sensitivity (0.87, 95% CI 0.75, 0.94) and specificity (0.96, 95% CI 0.91, 0.99) (P<0.05). Study sensitivity was not correlated with the prevalence of pancreatic lesions (R=0.1076, P=0.3247).

CONCLUSION

A limited number of small studies suggest that DWI is a potentially technically feasible measure to differentiate malignant from benign pancreatic lesions. However, it is still controversial and is limited in that it can only distinguish certain lesions. High-quality prospective studies on DWI for the discrimination of pancreatic lesions still need to be conducted.

Assessing treatment effect in pancreatic cancer

CONTEXT

Pancreatic cancer is one of the most deadly forms of cancer (43,140 new cases per year; 36,800 deaths), and most people with pancreatic cancer do not survive past 5 years. New therapeutic regimens are constantly being evaluated in an attempt to reduce the rapid progression of this disease. Although some patients receive neoadjuvant therapy in an attempt to make a nonresectable or borderline-resectable tumor resectable, more patients with resectable disease are being enrolled in clinical trials that provide neoadjuvant therapy. This means more pancreatic resections must be evaluated for therapy effect. Histologic grading schemes for the assessment of posttherapy response have been described, but difficulties associated with determining the histologic features of treatment effect in pancreatic cancer have not been addressed.

OBJECTIVES

To critically review the diagnostic criteria for proposed grading schemes for pancreatic cancer treated with neoadjuvant chemoradiation therapy and to provide guidance to surgical pathologists who encounter treated pancreatic cancer resections.

DATA SOURCES

Published peer-reviewed literature and the personal experience of the authors.

CONCLUSIONS

Assessment of treatment effect in pancreatic cancer is difficult. Pathologists need to be aware that some histologic features of treatment effect overlap with histologic features seen in untreated pancreatic cancer, such as tumor cell anaplasia, necrosis, and fibrosis. Careful assessment of pancreatic resections, including detailed gross examination and thorough histologic sampling, is important in accurately assessing treatment effect and improving patient outcomes.

Clinical usefulness of diffusion-weighted MR imaging for detection of pancreatic cancer: comparison with enhanced multidetector-row CT

PURPOSE

The aim of this study was to compare diffusion-weighted magnetic resonance imaging (DWI) and multidetector-row computed tomography (MDCT) for detection of primary pancreatic cancer by reviewing images of patients at high risk for pancreatic cancer with main pancreatic duct (MPD) dilatation shown by magnetic resonance cholangiopancreatography (MRCP).

METHODS

From October 2007 to September 2009, 83 patients who had undergone both DWI and MDCT with MPD dilatation were identified and were reviewed by four readers (2 radiologists and 2 gastroenterology fellows). Diagnostic performance in pancreatic cancer detection was evaluated with 95% confidence intervals. Statistically significant differences in the detection of pancreatic cancer between DWI and MDCT were compared by receiver operating characteristics and the confidence of the diagnosis by the paired t test.

RESULTS

Thirty-two of 83 patients were diagnosed with primary pancreatic cancer by histological evaluation of 15 surgical and 2 endoscopic ultrasound-guided fine needle aspiration samples, and by the clinical course for 15 lesions. Overall average accuracies of pancreatic cancer detection by the four readers were 84% with DWI and 86% with MDCT.

CONCLUSION

Performance of DWI and MDCT was equivocal for detection of pancreatic cancer in a high-risk population with MPD dilatation. The combination of MRCP and DWI for detection of pancreatic cancer allowed identification of a high-risk population and tumor detection with a single imaging modality with no need for contrast medium.

Staging cancer of the pancreas

Pancreatic carcinoma is the fourth cause of death from cancer in the United States, with a survival rate at 5 years of less than 5%. About 60% of tumors originate at the head of the pancreas, 15% in the body, 5% in the tail; 20% are diffuse within the pancreas. This article discusses the imaging and staging of pancreatic cancer.

Vascular invasion in pancreatic cancer: Imaging modalities, preoperative diagnosis and surgical management

Pancreatic cancer is associated with a poor prognosis, and surgical resection remains the only chance for curative therapy. In the absence of metastatic disease, which would preclude resection, assessment of vascular invasion is an important parameter for determining resectability of pancreatic cancer. A frequent error is to misdiagnose an involved major vessel. Obviously, surgical exploration with pathological examination remains the “gold standard” in terms of evaluation of resectability, especially from the point of view of vascular involvement. However, current imaging modalities have improved and allow detection of vascular invasion with more accuracy. A venous resection in pancreatic cancer is a feasible technique and relatively reliable. Nevertheless, a survival benefit is not achieved by curative resection in patients with pancreatic cancer and vascular invasion. Although the discovery of an arterial invasion during the operation might require an aggressive management, discovery before the operation should be considered as a contraindication. Detection of vascular invasion remains one of the most important challenges in pancreatic surgery. The aim of this article is to provide a complete review of the different imaging modalities in the detection of vascular invasion in pancreatic cancer.

Screening of high-risk families for pancreatic cancer

PURPOSE OF REVIEW

To discuss how to recognise and manage high-risk individuals.

RECENT FINDINGS

Publication of initial results of screening for pancreatic cancer from US centres. Several masses and premalignant lesions have been detected, but the detection of the first pancreatic cancer through an organised study of screening has yet to be published. There has been progress in risk stratification; the role of diabetes in predisposing for cancer has been characterised and molecular modalities have been published which could be used in conjunction with imaging in a screening programme. A mutation in the palladin gene was found to segregate with the disease in a family with a clear predisposition for pancreatic cancer, though this has yet to be found in other such kindreds.

SUMMARY

Significant challenges remain to be solved in screening for early pancreatic cancer. Risk stratification needs to be improved and high-risk patients included in research-based screening programmes. It will be impossible to confirm that screening can detect cancers early enough for curative treatment until the results of these prospective studies become available.

Magnetic resonance imaging of adenocarcinoma of the pancreas

Magnetic resonance imaging (MRI) is a valuable tool in the assessment of the full spectrum of pancreatic disease. A standard MR protocol including noncontrast T1-weighted fat-suppressed and dynamic gadolinium-enhanced gradient-echo imagings is sensitive for the evaluation of pancreatic cancer. Optimal use of MRI in the investigation of pancreatic cancer occurs in the following circumstances: (1) detection of small non-contour-deforming tumors, (2) evaluation of local extension and vascular encasement, (3) determination of the presence of lymph node and peritoneal metastases, and (4) determination and characterization of associated liver lesions and liver metastases. The objective of this study was to describe the attribute of MRI for evaluating pancreatic cancer.

In vivo characterization of proliferation for discriminating cancer from pancreatic pseudotumors

We have determined the ability of PET with the thymidine analog 3'-deoxy-3'-(18)F-fluorothymidine (FLT) to detect pancreatic cancer and to differentiate malignant from benign pancreatic lesions.

METHODS

In this prospective study, (18)F-FLT PET was performed on 31 patients with undefined pancreatic lesions. Routine diagnostic procedures included endoscopic ultrasound, MRI, or multislice helical CT of the upper gastrointestinal tract in all patients. Uptake of (18)F-FLT was evaluated semiquantitatively by calculation of mean and maximal standardized uptake values (SUVs). Results were correlated to the reference methods, which were histopathology (23/31) or cytology/clinical follow-up (8/31).

RESULTS

All 10 benign pancreatic lesions were negative on (18)F-FLT PET and showed only background activity (specificity, 100%; 90% confidence interval, 74%-100%). On visual interpretation, 15 of 21 malignant tumors presented as focal (18)F-FLT uptake higher than the surrounding background (sensitivity, 71.4%; 90% confidence interval, 52%-89%). (18)F-FLT PET missed 4 well-differentiated and 2 T1 cancers. Mean (18)F-FLT uptake was 3.1 in all malignant tumors (median, 2.8; range, 1.3-8.5), 3.7 in tumors with visual tracer uptake (median, 3.2; range, 2.1-8.5), and significantly higher in malignant than in benign tumors (mean/median, 1.4; range, 1.2-1.7; P<0.001). For discriminating cancer from benign pancreatic lesions, receiver-operating-characteristic analysis indicated a sensitivity of 81% and specificity of 100% (area under the curve, 0.93) using a mean (18)F-FLT SUV cutoff of 1.8 (maximal (18)F-FLT SUV: area under the curve, 0.92; SUV cutoff, 2.1).

CONCLUSION

In this pilot study, focal uptake of the in vivo proliferation marker (18)F-FLT was detected exclusively in malignant tumors. (18)F-FLT PET may therefore be useful as a diagnostic adjunct for differentiating cancer from benign pancreatic lesions.

Early detection of pancreatic cancer: the Japanese approach

Pancreatic cancer is the fifth leading cause of cancer-related deaths in Japan. Small pancreatic cancers have some abnormal findings on ultrasonography, and diagnosis with endosonography is useful. Positron emission tomography and contrast-enhanced ultrasonography are expected to serve as new modalities for the early detection of pancreatic cancer. The identification of high-risk individuals is necessary to perform efficient screening. Intraductal papillary mucinous neoplasms and chronic pancreatitis are important risk factors for pancreatic cancer.

Survival in pancreatic carcinoma based on tumor size

OBJECTIVES

The size of pancreatic tumors that can be diagnosed by preoperative imaging continues to decrease because advances in diagnostic imaging. Several surgical series have suggested that survival is better in tumors 20 mm or smaller (vs tumors >20 mm), but the incremental benefit of diagnosing progressively smaller tumors from 30 mm (currently, the average size of pancreatic tumor at diagnosis) to 20 mm or smaller is not known. We investigated survival and resectability as tumor size increased from 20 mm or smaller to 30 mm or larger.

METHODS

This is a retrospective analysis of consecutive patients with pancreatic cancer, who underwent endoscopic ultrasound-guided fine-needle aspiration at MD Anderson Cancer Center between December 2000 and December 2001. Tumor size was based on the combination of endoscopic ultrasound and computed tomography imaging.

RESULTS

The median (+/-SE) for tumors 20 mm or smaller, 21 to 25 mm, 26 to 30 mm and larger than 30 mm was 17.2 +/- 8.2, 12.3 +/- 4.9, 8.5 +/- 3.6, and 7.6 +/- 1.2 months (P = 0.021), respectively. Tumors were resectable in 10 (83%) of 12 tumors 20 mm or smaller, 8 (67%) of 12 tumors 21 to 25 mm, 5 (36%) of 14 of tumors 26 to 30 mm, and 2 (7%) of 27 tumors larger than 30 mm (P < 0.001).

CONCLUSIONS

A dramatic change in survival occurs as the size of pancreatic tumor increases from 20 mm or smaller to 30 mm or larger. To be effective, future strategies for early diagnosis of pancreatic cancer should aim at diagnosing most pancreatic cancers before they are 20 mm in size.

Interpreting trends of pancreatic cancer incidence and mortality: a nation-wide study in Sweden (1960-2003)

OBJECTIVE

We investigated temporal trends of pancreatic cancer in Sweden measured with suboptimal sensitivity and specificity both by incidence and by mortality rates.

METHODS

46,257 incident cases of pancreatic cancer from the Swedish Cancer Register and 53,686 mortality cases from the Causes of Death Register during 1960-2003 were used to calculate age-standardized incidence or mortality rates. We further assessed the impact of changes in diagnostic practice on the observed trends, and investigated the effect of calendar period and birth cohort by age-period-cohort modeling.

RESULTS

Overall, the pattern of trends in age-adjusted rates of pancreatic cancer was similar irrespective of whether incidence or mortality was used. The age-adjusted rates of pancreatic cancer increased during the first decade and then peaked for both sexes (the male peak occurred in the early 1970s and the female peak in the 1980s) followed by a steady decline in both groups. An age-period model provided the best fit to the observed trends among patients diagnosed at ages 35-74 in both sexes.

CONCLUSION

The close agreement between the incidence and mortality and the gender disparity suggest a true decline in pancreatic cancer incidence in recent years in Sweden, and gender-specific trends in exposure to environmental risk factors.

Hereditary cancer syndrome diagnosis: molecular genetic clues and cancer control

Oncologists who are aware of the progress in hereditary cancer syndrome diagnosis, and, in particular, of how this effort may be effectively facilitated through a comprehensive family history in concert with molecular genetic studies, are in the envious position of designing highly targeted screening and management programs for the membership of these cancer-prone families. The Lynch syndrome is discussed as a clinical model wherein the presence of mismatch repair mutations provides a high level of diagnostic certainty for the initiation of targeted cancer screening and management. The familial atypical multiple mole melanoma-pancreatic cancer (FAMMM-PC) syndrome, on the other hand, provides another model with cancer-control potential. Given its phenotypic features of multiple atypical nevi, high total body mole count and cutaneous malignant melanoma, coupled with the integral association of PC in a subset of FAMMM kindreds with the CDKN2A germline mutation, this may result in a perhaps lower level of diagnostic certainty when compared with the Lynch syndrome. This knowledge may impact upon progress in the earlier diagnosis of melanoma and provide an impetus for creative diagnostic methods in PC, a disease that, at this time, demonstrates a mortality rate virtually identical to its incidence rate.

Role of positron emission tomography in decisions on treatment strategies for pancreatic cancer

BACKGROUND/PURPOSE

The purpose of this study was to estimate the usefulness of positron emission tomography (PET) in deciding on strategies for the treatment of pancreatic cancer. The following two parameters were evaluated: the ability of PET to provide an estimation of the progression of pancreatic cancer, and the ability of PET to predict survival and the effect of chemoradiotherapy.

METHODS

Forty-two patients underwent PET as part of the procedure for making a diagnosis of pancreatic tumors. The maximum standardized uptake value (SUVmax) levels were compared with clinicopathological factors and analyzed.

RESULTS

PET provided a sensitivity of 87%, a specificity of 67%, and an overall accuracy of 85% for the diagnosis of pancreatic malignancy. Tumors with distant metastases showed significantly higher SUV levels than tumors without metastasis. In the patients who received chemoradiotherapy, the overall survival of the group in which SUVmax was less than 7.0 was better than that of the group in which SUVmax was more than 7.0.

CONCLUSIONS

We conclude that PET is a useful tool for determining pathological status and distant metastasis in pancreatic cancer, and for predicting the prognosis of patients receiving chemoradiotherapy.

Peutz-Jeghers syndrome and screening for pancreatic cancer

BACKGROUND

Cancer risk, including pancreatic, is high in those with Peutz-Jeghers syndrome (PJS). It has been suggested that such patients should undergo screening for pancreatic cancer.

METHODS

The risk of pancreatic cancer in PJS, pancreatic screening and potential screening strategies were reviewed. Cost-effectiveness was assessed according to American Gastroenterology Association guidelines and a risk stratification model proposed by the European Registry of Hereditary Pancreatitis and Familial Pancreatic Cancer.

RESULTS

The risk of pancreatic cancer is increased in PJS but screening would cost over US 35,000 dollars per life saved. Risk stratification reduces cost by 100,000 dollars and costs fall to 50,000 dollars per life saved if deaths from other forms of cancer are avoided.

CONCLUSION

Screening should be performed only on a research basis to evaluate the benefit and cost-effectiveness in high-risk groups.

IRM et maladies pancréatiques

Magnetic resonance (MR) imaging of the pancreas has undergone a major change because it can provide noninvasive images of the pancreatic ducts and the parenchyma. MR cholangiopancreatography (MRCP) enables detection of anatomic variants such as pancreas divisum. Although contrast material-enhanced CT is still considered the gold standard in acute pancreatitis and for the detection of calcifications in chronic pancreatitis, MR imaging and secretin-enhanced MRCP are useful in evaluating pseudocysts and pancreatic disruption. The role of MR is still debated in pancreatic neoplasms except the cystic lesions where MR imaging provides critical information regarding the lesion's content and a possible communication with the pancreatic ducts. MRCP and MR of the pancreas are also useful in identifying other pancreatic diseases such as lymphoplasmocytic pancreatitis and groove pancreatitis.

Current treatment strategies for pancreatic cancer in the elderly

Pancreatic cancer, which is responsible for >90% of exocrine pancreatic tumours, is typically a disease of the elderly (> or =70 years of age). However, older patients are less likely to be staged than younger patients despite having a worse overall 5-year survival rate than their younger counterparts. Various radiological, ultrasonographic and endoscopic investigations are used not only as diagnostic tools but also to accurately stage the cancer for possible surgery. Many patients with pancreatic cancer have mutations of the K-ras oncogene, and various tumour suppressor genes are also inactivated. Pancreas resection can be performed in elderly resectable patients without excess mortality, even in those >80 years of age. However, treatment for locally advanced, unresectable and metastatic pancreatic cancer is palliative. Fluorouracil-based chemoradiation for locally advanced or unresectable cancer, and gemcitabine for patients with metastatic disease, can result in clinical benefits. Placement of a stent in the biliary tract has been shown to improve symptoms of obstructive jaundice or ascites, as well as quality of life. As molecular targets are identified, interventions with targeted specific agents may improve tumour control. However, further studies will be needed to demonstrate whether or not various agents targeting signal transduction pathways or nuclear transcription factors are useful for elderly patients with advanced pancreatic cancer.

Clinical Results on Intra-arterial Adjuvant Chemotherapy for Prevention of Liver Metastasis Following Curative Resection of Pancreatic Cancer

BACKGROUND

We report here the clinical results of intra-arterial adjuvant chemotherapy for the prevention of liver metastasis following curative resection of pancreatic carcinoma.

METHODS

Twenty-two patients with pancreatic cancer underwent the radical operation between January 1999 and April 2005. Intra-arterial adjuvant chemotherapy with cisplatin (CDDP) and 5-fluorouracil (5FU) was selectively performed on nine patients; the remaining 13 patients did not receive chemotherapy and comprised the control group.

RESULTS

Demographics and clinical characteristics were almost identical in the two groups. Liver metastasis occurred in three of nine patients (33%) in the chemotherapy group and in seven of 13 patients (54%) in the control group. The intra-arterial adjuvant chemotherapy had the tendency to suppress the rate of liver metastasis. The median survival period was 15.8 months for the nine patients who underwent the intra-arterial adjuvant chemotherapy following surgery and 13.4 months for the 13 patients of the control group who were curatively resected without the intra-arterial adjuvant chemotherapy. Cumulative survival rate was improved by the intra-arterial adjuvant chemotherapy.

CONCLUSIONS

In patients with pancreatic cancer who underwent the curative operation, the intra-arterial adjuvant chemotherapy had the tendency to suppress the rate of liver metastasis and improve cumulative survival.

A family history of pancreatic cancer

BACKGROUND

A 65-year-old white male with a family history of pancreatic cancer and a personal history of two episodes of acute pancreatitis was referred to our department in January 2005 by his primary-care physician for an assessment of his pancreatic cancer risk.

INVESTIGATIONS

Physical exam, laboratory investigations, CT scan, endoscopic ultrasonography, endoscopic retrograde cholangiopancreatography.

DIAGNOSIS

Familial pancreatic cancer.

MANAGEMENT

Subtotal pancreatectomy, referral to genetic counselor, and continued surveillance.

Diagnóstico y estadificación del carcinoma de páncreas (I)

Carcinoma of the pancreas is a neoplasm with a poor prognosis that is diagnosed in the advanced stages in most patients. Given that surgical resection is the only potentially curative treatment for this disease, it is of the utmost importance to appropriately select the group of patients with initial stage pancreatic tumors that have not extended and can therefore be resected. Several different imaging techniques can be used for this purpose: ultrasonography (US), computed tomography (CT), magnetic resonance (MR), as well as the recent additions of endoscopic ultrasonography (EUS) and positron emission tomography (PET). Other techniques, such as laparoscopy and laparoscopic ultrasonography, also play a role in the diagnosis and staging of these patients. Continual technological developments in each of the above-mentioned techniques have led to reiterated updates in the scientific literature throughout the last two decades. This review aims to evaluate each of these techniques and present diagnostic algorithms reflected in the literature in order to achieve the greatest diagnostic accuracy in determining the extent of the disease so that unnecessary surgery can be avoided in cases not susceptible to resection.

Evidence-based diagnosis and staging of pancreatic cancer

Only 20% of patients who present with pancreatic cancer will be amenable to potentially curative resection. Therefore, it is necessary to reliably identify patients who might benefit from major surgical intervention by employing the appropriate staging methods. In this review, the pros and cons of each imaging technique are discussed and an algorithm for single and combined use of the different imaging modalities is proposed. To date, contrast-enhanced multi-detector row helical CT (MDR-CT) together with endoscopic ultrasound (EUS) remain the first staging methods of choice. MDR-CT has a high sensitivity for identifying vascular invasion and EUS is able to detect lesions as small as 2-3 mm. ERCP is performed mainly in patients with biliary obstruction with the option for therapeutic intervention during the same session. MRI with MR-angiography, MRCP, PET/CT and staging laparoscopy are additional modalities which might give further information in cases of equivocal findings by MDR-CT and EUS. The role of tumour markers such as CA 19-9 and CEA is reserved for monitoring and diagnosing post-surgery recurrence. Cytological or histological confirmation should usually be performed in patients that are not eligible for surgery prior to the commencement of palliative radio- or chemotherapy. In the routine clinical setting, MDR-CT and EUS play the predominant roles by providing the most cost-effective and accurate means for diagnosing and staging most cases of pancreatic cancer.

PET in abdominal pathology: advantages and limitations

New oncologic procedures are currently more focused on the biological features of tumors. The ideal objective is the administration of personalized effective treatments for each patient that affects not just the location and spread of disease but also special metabolic characteristics of tumoral cells. Radiologic diagnostic methods are extremely important in the management of the patient for staging, restaging, and evaluation of treatment response, and clinicians are avid for some additional functional and metabolic information. Further, they need more dynamic methods for follow-up. Nuclear Medicine and positron emission tomography (PET) in many cases can meet this requirement, although it is not perfect, at least at the present time. Currently 2-((18)F)fluoro-2-desoxi-D: -glucose positron emission tomography is being widely used for oncologic purposes. Its information can be very useful in abdominal diseases and must be taken into account with the results of radiologic imaging. Thus, many changes in the choice of treatment are seen. However, it is very important to know that sometimes there is a lack of specificity that has to be considered.

Mangafodipir trisodium-enhanced MR imaging of pancreatic disease

Our study aimed to assess the diagnostic capabilities of mangafodipir trisodium-enhanced MRI for the evaluation of pancreatic disease. Sixty-three patients suspected of having pancreatic disease underwent MRI with a 1.5-T device. After the acquisition of axial and coronal T2-weighted sequences, the MR protocol included T1-weighted fat-suppressed breath-hold SPGR images obtained before and 30 min after the infusion of Mn-DPDP (Teslascan). The detection of a focal pancreatic lesion and its intensity were evaluated in consensus by two observers, who also attempted to characterize each lesion as benign or malignant. The reviewers were blinded to patient identification and all clinical, laboratory and previous imaging findings. MR imaging results were correlated with surgery (n=37), laparoscopy (n=1), biopsy (n=2) and imaging follow-up (n=22). Sixty-two subjects were effectively included in our analysis because one patient was lost to follow-up; final malignant and benign diagnoses were determined in 22 (35%) and 29 (47%) of the patients, respectively. The level of confidence in the diagnosis of the pancreatic lesion was significantly increased by the administration of Mn-DPDP as demonstrated by ROC analysis of unenhanced and post-contrast image sets (P=0.009). Overall, on the basis of observers' readings, MR assessment of pancreatic disease resulted in 57 correct diagnoses (accuracy, 92%) and five (8%) incorrect diagnoses. The sensitivity, specificity, positive predictive value and negative predictive value of the reviewers for the detection of pancreatic lesions and for the differentiation between benign and malignant masses were 91% (95% CI: 84 and 98%), 93% (95% CI: 86 and 99%), 87% (95% CI: 79 and 95%) and 95% (95% CI: 89 and 100%), respectively. Mn-DPDP-enhanced MRI is an effective diagnostic tool for evaluating pancreatic disease.