The clinical usefulness of 18F-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) in follow-up of curatively resected pancreatic cancer patients

Role of molecular imaging in prognosis, diagnosis, and treatment of gastrointestinal cancers: An update on new therapeutic methods

One of the leading causes of cancer-related death is gastrointestinal cancer, which has a significant morbidity and mortality rate. Although preoperative risk assessment is essential for directing patient care, its biological behavior cannot be accurately predicted by conventional imaging investigations. Potential pathophysiological information in anatomical imaging that cannot be visually identified can now be converted into high-dimensional quantitative image features thanks to the developing discipline of molecular imaging. In order to enable molecular tissue profile in vivo, molecular imaging has most recently been utilized to phenotype the expression of single receptors and targets of biological therapy. It is expected that molecular imaging will become increasingly important in the near future, driven by the expanding range of biological therapies for cancer. With this live molecular fingerprinting, molecular imaging can be utilized to drive expression-tailored customized therapy. The technical aspects of molecular imaging are first briefly discussed in this review, followed by an examination of the most recent research on the diagnosis, prognosis, and potential future clinical methods of molecular imaging for GI tract malignancies.

Surveillance after surgery for pancreatic cancer: a global scoping review of guidelines and a nordic Survey of contemporary practice

OBJECTIVES

Most patients with pancreatic cancer who have undergone surgical resection eventually develop disease recurrence. ‍This study aimed to investigate whether there is evidence to support routine surveillance after pancreatic cancer surgery, with a secondary aim of analyzing the implementation of surveillance strategies in the Nordic countries.

MATERIALS AND METHODS

A scoping review was conducted to identify clinical practice guidelines globally and research studies relating to surveillance after pancreatic cancer resection. This was followed by a survey among 20 pancreatic units from four Nordic countries to assess their current practice of follow-up for operated patients.

RESULTS

Altogether 16 clinical practice guidelines and 17 research studies were included. The guidelines provided inconsistent recommendations regarding postoperative surveillance of pancreatic cancer. The clinical research data were mainly based on retrospective cohort studies with low level of evidence and lead-time bias was not addressed. Active surveillance was recommended in Sweden and Denmark, but not in Norway beyond the post-operative/adjuvant period. Finland had no national recommendations for surveillance. The Nordic survey revealed a wide variation in reported practice among the different units. About 75% (15 of 20 units) performed routine postoperative surveillance. Routine CA 19-9 testing was used by 80% and routine CT by 67% as part of surveillance. About 73% of centers continued follow-up until 5 years postoperatively.

CONCLUSION

Evidence for routine long-term (i.e. 5 years) surveillance after pancreatic cancer surgery remains limited. Most pancreatic units in the Nordic countries conduct regular follow-up, but protocols vary.

Prediction of Isolated Local Recurrence After Resection of Pancreatic Ductal Adenocarcinoma: A Nationwide Study

BACKGROUND

Distinguishing postoperative fibrosis from isolated local recurrence (ILR) after resection of pancreatic ductal adenocarcinoma (PDAC) is challenging. A prognostic model that helps to identify patients at risk of ILR can assist clinicians when evaluating patients' postoperative imaging. This nationwide study aimed to develop a clinically applicable prognostic model for ILR after PDAC resection.

PATIENTS AND METHODS

An observational cohort study was performed, including all patients who underwent PDAC resection in the Netherlands (2014-2019; NCT04605237). On the basis of recurrence location (ILR, systemic, or both), multivariable cause-specific Cox-proportional hazard analysis was conducted to identify predictors for ILR and presented as hazard ratios (HRs) with 95% confidence intervals (CIs). A predictive model was developed using Akaike's Information Criterion, and bootstrapped discrimination and calibration indices were assessed.

RESULTS

Among 1194/1693 patients (71%) with recurrence, 252 patients (21%) developed ILR. Independent predictors for ILR were resectability status (borderline versus resectable, HR 1.42; 95% CI 1.03-1.96; P = 0.03, and locally advanced versus resectable, HR 1.11; 95% CI 0.68-1.82; P = 0.66), tumor location (head versus body/tail, HR 1.50; 95% CI 1.00-2.25; P = 0.05), vascular resection (HR 1.86; 95% CI 1.41-2.45; P < 0.001), perineural invasion (HR 1.47; 95% CI 1.01-2.13; P = 0.02), number of positive lymph nodes (HR 1.04; 95% CI 1.01-1.08; P = 0.02), and resection margin status (R1 < 1 mm versus R0 ≥ 1 mm, HR 1.64; 95% CI 1.25-2.14; P < 0.001). Moderate performance (concordance index 0.66) with adequate calibration (slope 0.99) was achieved.

CONCLUSIONS

This nationwide study identified factors predictive of ILR after PDAC resection. Our prognostic model, available through www.pancreascalculator.com , can be utilized to identify patients with a higher a priori risk of developing ILR, providing important information in patient evaluation and prognostication.

Dynamics of Serum CA19-9 in Patients Undergoing Pancreatic Cancer Resection

BACKGROUND

Carbohydrate antigen (CA) 19-9 is an established perioperative prognostic biomarker for pancreatic ductal adenocarcinoma (PDAC). However, it is unclear how CA19-9 monitoring should be used during postoperative surveillance to detect recurrence and to guide the initiation of recurrence-focused therapy.

OBJECTIVE

This study aimed to elucidate the value of CA19-9 as a diagnostic biomarker for disease recurrence in patients who underwent PDAC resection.

METHODS

Serum CA19-9 levels at diagnosis, after surgery, and during postoperative follow-up were analyzed in patients who underwent PDAC resection. All patients with at least two postoperative follow-up CA19-9 measurements before recurrence were included. Patients deemed to be nonsecretors of CA19-9 were excluded. The relative increase in postoperative CA19-9 was calculated for each patient by dividing the maximum postoperative CA19-9 value by the first postoperative value. Receiver operating characteristic analysis was performed to identify the optimal threshold for the relative increase in CA19-9 levels to identify recurrence in the training set using Youden's index. The performance of this cutoff was validated in a test set by calculating the area under the curve (AUC) and was compared to the performance of the optimal cutoff for postoperative CA19-9 measurements as a continuous value. In addition, sensitivity, specificity, and predictive values were assessed.

RESULTS

In total, 271 patients were included, of whom 208 (77%) developed recurrence. Receiver operating characteristic analysis demonstrated that a relative increase in postoperative serum CA19-9 of 2.6× was predictive of recurrence, with 58% sensitivity, 83% specificity, 95% positive predictive value, and 28% negative predictive value. The AUC for a 2.6× relative increase in the CA19-9 level was 0.719 in the training set and 0.663 in the test set. The AUC of postoperative CA19-9 as a continuous value (optimal threshold, 52) was 0.671 in the training set. In the training set, the detection of a 2.6-fold increase in CA19-9 preceded the detection of recurrence by a mean difference of 7 months ( P <0.001) and in the test set by 10 months ( P <0.001).

CONCLUSIONS

A relative increase in the postoperative serum CA19-9 level of 2.6-fold is a stronger predictive marker for recurrence than a continuous CA19-9 cutoff. A relative CA19-9 increase can precede the detection of recurrence on imaging for up to 7 to 10 months. Therefore, CA19-9 dynamics can be used as a biomarker to guide the initiation of recurrence-focused treatment.

Utility of MRI in detection of PET-CT proven local recurrence of pancreatic adenocarcinoma after surgery

The aim of this prospective study was to investigate the accuracy and inter-observer reliability of MRI in detection of local recurrence (LR) of pancreatic adenocarcinoma (PAC) after surgery, which was proved by PET-CT and access correlation between functional MRI and PET parameters. Forty-five patients who underwent PET-CT and MRI for follow-up purposes after radical operation of PAC were included. Twenty-three were PET positive (study group) and 22 negative for LR (control group). MR examination was performed within one month after PET-CT and three readers who were blind for PET-CT findings searched LR in T2W, 3D-dynamic post-contrast T1W-FS and DWI sequences, respectively. Sensitivity and specificity were calculated while inter-reader agreement was estimated by Cronbach's Alpha reliability coefficient (CARC). Apparent diffusion coefficient (ADC) of LR was correlated with the size (maximal diameter) and functional PET-CT parameters: mean and maximum standardized uptake values (SUVmean, SUVmax), metabolic tumor volume (MTV) and total lesion glycolysis (TLG), using Spearman's correlation coefficient (rS). Sensitivity and specificity among three readers in detecting the LR were 70% and 77-84% in T2W (CARC 0.806), 91-100% and 100% in 3D post-contrast T1W-FS (CARC 0.980), and both 100% in DWI sequences (CARC 1.000). Moderate inverse correlation was found between the ADC and SUVmean (rS = - 0.484), MTV (rS = - 0.494), TLG (rS = - 0.519) and lesion size (rS = - 0.567). MRI with DWI shows high diagnostic accuracy in detecting the LR of PAC in comparison to PET-CT as reference standard. ADC significantly inversely correlates with standard and advanced PET parameters and size of LR.

Preoperative carbohydrate antigen 19-9 and standard uptake value of positron emission tomography-computed tomography as prognostic markers in patients with pancreatic ductal adenocarcinoma

BACKGROUND

Among various prognostic factors of pancreatic cancer, preoperative clinical information is obtained by imaging modality. This study aimed to evaluate clinical usefulness of preoperative carbohydrate antigen and preoperative standard uptake value in 18F-fluorodeoxyglucose positron emission tomography as predictive biological markers for resectable pancreatic ductal adenocarcinoma.

METHODS

A total of 189 patients with PDAC who underwent preoperative PET-computed tomography were evaluated. Patients underwent neoadjuvant chemotherapy, and R2 resection was excluded. The correlation between SUVmax and clinicopathologic parameters was analyzed. The C-tree statistical method was used to estimate cutoff values of logCA19-9 and SUVmax for survival rate. A multivariate analysis was conducted to identify prognostic factors for overall survival.

RESULTS

The median duration of OS was 26 months, and the 5-year survival rate was 22.4%. The optimal cutoff values for CA19-9 level was 150 U/mL and SUVmax was 5.5. When subjects were divided into three groups according to the combination of CA19-9 level and SUVmax from C-tree (high-risk group, CA19-9 > 150 U/mL and SUVmax > 5.5; intermediate-risk group, CA19-9 ≤ 150 U/mL and SUVmax > 5.5 or CA19-9 > 150 U/mL and SUVmax ≤ 5.5; and low-risk group, CA19-9 ≤ 150 U/mL and SUVmax ≤ 5.5), there was a significant 5YSR difference (5.6%, 24.3%, and 36.5%, P < .001). The multivariate analysis revealed high SUVmax, high preoperative CA19-9 level, venous invasion, and adjuvant chemotherapy were prognostic factors of OS.

CONCLUSIONS

CA19-9 and SUVmax are strong prognostic biological factors in resectable PDAC. Moreover, patients with high CA19-9 level and SUVmax are not indicated for upfront surgery.

The Diagnostic Performance of 18F-FDG PET/CT in Recurrent Pancreatic Cancer: A Systematic Review and Meta-analysis

Purpose

The CT scan is the best common screening test for pancreatic cancer recurrence after surgery. The goal of our meta-analysis was to assess the diagnostic accuracy of 18F-FDG PET/CT for pancreatic cancer recurrence.

Methods

We examined PubMed and Embase for suitable papers between 2009 and 2022. The researchers considered studies that looked at the diagnostic usefulness of 18F-FDG PET/CT in identifying local and/or distant disease recurrence throughout the follow-up following pancreatic cancer resection. The Quality Assessment of Diagnostic Performance Studies-2 (QUADAS-2) method was used to evaluate the quality of each study. For each of the publications included, two researchers extracted data independently. The extracted data included general data (authors, year of publication), literature characteristics (country, type of literature, and design of study), characteristics of the patient (patients' number, mean or median age, and treatment regimen), and technical aspects (scanner, injection activity, and image analysis).

Results

The analysis includes 7 trials with a total of 263 patients. The sensitivity and specificity of 18F-FDG PET/CT in detecting recurrent pancreatic cancer following definitive treatment were 0.89 (95 percent CI: 0.83-0.93) and 0.88 (95 percent CI: 0.72-0.96), respectively, according to the pooled estimates. PET/CT performed well in the diagnosis of recurrent pancreatic cancer, with an AUC of 0.94. (0.91-0.95).

Conclusions

18F-FDG PET-CT was found to be a reliable detection method in recurrent pancreatic tumor.

Artificial Intelligence Algorithm-Based Computerized Tomography Image Features Combined with Serum Tumor Markers for Diagnosis of Pancreatic Cancer

The objective of this study was to analyze the value of artificial intelligence algorithm-based computerized tomography (CT) image combined with serum tumor markers for diagnoses of pancreatic cancer. In the study, 68 hospitalized patients with pancreatic cancer were selected as the experimental group, and 68 hospitalized patients with chronic pancreatitis were selected as the control group, all underwent CT imaging. An image segmentation algorithm on account of two-dimensional (2D)-three-dimensional (3D) convolution neural network (CNN) was proposed. It also introduced full convolutional network (FCN) and UNet network algorithm. The diagnostic performance of CT, serum carbohydrate antigen-50 (CA-50), serum carbohydrate antigen-199 (CA-199), serum carbohydrate antigen-242 (CA-242), combined detection of tumor markers, and CT-combined tumor marker testing (CT-STUM) for pancreatic cancer were compared and analyzed. The results showed that the average Dice coefficient of 2D-3D training was 84.27%, which was higher than that of 2D and 3D CNNs. During the test, the maximum and average Dice coefficient of the 2D-3D CNN algorithm was 90.75% and 84.32%, respectively, which were higher than the other two algorithms, and the differences were statistically significant (P < 0.05). The penetration ratio of pancreatic duct in the experimental group was lower than that in the control group, the rest were higher than that in the control group, and the differences were statistically significant (P < 0.05). CA-50, CA-199, and CA-242 in the experimental group were 141.72 U/mL, 1548.24 U/mL, and 83.65 U/mL, respectively, which were higher than those in the control group, and the differences were statistically significant (P < 0.05). The sensitivity, specificity, positive predictive value, and authenticity of combined detection of serum tumor markers were higher than those of CA-50, CA-199, and CA-242, and the differences were statistically significant (P < 0.05). The results showed that the proposed algorithm 2D-3D CNN had good stability and image segmentation performance. CT-STUM had high sensitivity and specificity in diagnoses of pancreatic cancer.

Korean clinical practice guideline for pancreatic cancer 2021: A summary of evidence-based, multi-disciplinary diagnostic and therapeutic approaches

Pancreatic cancer is the eighth most common cancer and the fifth most common cause of cancer-related death in Korea. To enable standardization of management and facilitate improvements in outcome, a total of 53 multi-disciplinary experts in gastroenterology, surgery, medical oncology, radiation oncology, radiology, nuclear medicine, and pathology in Korea developed new recommendations that integrate the most up-to-date, evidence-based research findings and expert opinions. Recommendations were made on imaging diagnosis, endoscopic management, surgery, radiotherapy, palliative chemotherapy, and specific management procedures, including neoadjuvant treatment or adjuvant treatment for patients with resectable, borderline resectable, and locally advanced unresectable pancreatic cancer. This is the English version of the Korean clinical practice guideline for pancreatic cancer 2021. This guideline includes 20 clinical questions and 32 statements. This guideline represents the most standard guideline for the diagnosis and treatment of patients with pancreatic ductal adenocarcinoma in adults at this time in Korea. The authors believe that this guideline will provide useful and informative advice.

Iodine concentration and tissue attenuation in dual-energy contrast-enhanced CT as a potential quantitative parameter in early detection of local pancreatic carcinoma recurrence after surgical resection

PURPOSE

Due to the difficult differentiation from non-specific postoperative soft tissue formation (PSF), early diagnosis of pancreatic carcinoma recurrence remains challenging. Thus, we investigated the diagnostic potential of dual-energy (DE) contrast-enhanced CT.

METHOD

After potentially curative pancreatic carcinoma resection, 31 consecutive patients with PSF were examined via DE perfusion CT, acquiring 34 images (80 kVp/140 kVp) every 1.5 s, as the initial purpose of this study was evaluating CT-Perfusion. Corresponding time points of arterial, pancreatic, and early venous phase were calculated from bolus trigger times in prior conventional CT. Iodine and 120 kVp-equivalent images were calculated. Regions of interest were placed in each soft tissue formation. Diagnosis of local recurrence was confirmed by regular follow-up or histopathology.

RESULTS

Final diagnosis was local recurrence in 17 patients and non-specific PSF in 14 patients. Iodine concentrations in early venous phase were significantly higher in recurrent carcinoma than in non-specific PSF (1.47 mg/ml vs. 0.96 mg/ml, p = 0.007). In earlier contrast phases iodine concentrations tended to be higher, but not significantly. CT numbers in recurrent carcinoma in 120 kVp-equivalent images in venous phase were significantly higher, too (74HU vs 47HU, p = 0.002). ROC-curve analysis for iodine concentrations in early venous phase suggests a cut-off value of ≥ 1.55 mg/ml for local recurrence (AUC = 0.78, specificity = 1.0, sensitivity = 0.53) and for CT numbers in 120kVp-equivalent images a cut-off value of ≥ 57HU (AUC = 0.82, specificity = 0.82, sensitivity = 0.71).

CONCLUSION

In difficult cases, measuring iodine concentrations or CT numbers in PSF in (early) venous phase DECT could be a valuable additional parameter for differentiating local recurrence from non-specific PSF.

The clinical application of 18F-FDG PET/CT in pancreatic cancer: a narrative review

Pancreatic cancer is one of the worst prognoses of all malignant tumors, with an annual incidence near its annual mortality rate. To improve the prognosis of patients with pancreatic cancer, it is essential to diagnose and evaluate pancreatic cancer early. Imaging examinations play an essential role in tumor detection, staging, and surgical resection assessment and can provide reliable evidence for the diagnosis and treatment of pancreatic cancer. Currently, imaging techniques commonly used for pancreatic cancer include endoscopic ultrasound (EUS), conventional ultrasound, magnetic resonance imaging (MRI), multidetector spiral computed tomography (MDCT), positron emission tomography/computed tomography (PET/CT), and others PET/CT is a new imaging device composed of PET and CT. ¹⁸F-Fluorodeoxyglucose (¹⁸F-FDG) is a commonly used tracer in the clinic. Cancer cells are more robust than other ordinary cells in that they can ingest glucose, and the structure of glucose is similar to the structure of ¹⁸F-FDG. Therefore, after the injection of ¹⁸F-FDG, ¹⁸F-FDG in tumor cells appears very thick during PET scanning. Therefore, PET/CT can determine the metabolic capacity and anatomical position of pancreatic tumor cells in the body accurately diagnose the patient's condition and tumor location. It plays a vital role in early diagnosis and accurate staging, predicts survival, and monitors therapeutic effectiveness and pancreatic cancer recurrence. Although ¹⁸F-FDG PET/CT has limitations in identifying inflammatory diseases and tumors, it still has good development potential. This article reviews the clinical application of ¹⁸F-FDG PET/CT in pancreatic cancer.

FDG PET Hybrid Imaging

Molecular imaging with positron emission tomography (PET) using tumour-seeking radiopharmaceuticals has gained wide acceptance in oncology with many clinical applications. The hybrid imaging modality PET/CT (computed tomography) allows assessing molecular as well as morphologic information at the same time. Therefore, PET/CT represents an efficient tool for whole-body staging and re-staging within one imaging modality. In oncology, the glucose analogue 18-F-fluorodeoxyglucose (FDG) is the most widely used PET/CT radiopharmaceutical in clinical routine. FDG PET and FDG PET/CT have been used for staging and re-staging of tumour patients in numerous studies. This chapter will discuss the use and the main indications of FDG PET/CT in oncology with special emphasis on lung cancer, lymphoma, head and neck cancer, melanoma and breast cancer (among other tumour entities). A review of the current literature is given with respect to primary diagnosis, staging and diagnosis of recurrent disease. Besides its integral role in diagnosis, staging and re-staging of disease in oncology, there is increasing evidence that FDG PET/CT can be used for therapy response assessment (possibly influencing therapeutic management and treatment planning) by evaluating tumour control, which will also be discussed in this chapter.

The Utility of PET/Computed Tomography for Radiation Oncology Planning, Surveillance, and Prognosis Prediction of Gastrointestinal Tumors

At present, the strongest evidence for the use of PET/computed tomography (CT) in gastrointestinal (GI) malignancies is to rule out distant metastatic disease at diagnosis, radiation treatment planning for anal malignancies, and disease recurrence monitoring in colorectal and anal malignancies. Use of PET/CT for GI malignancies continues to evolve over time, with new studies evaluating prognostic abilities of PET/CT and with increasing sensitivity and spatial resolution of more modern PET/CT scanners. The authors encourage future applications and prospective evaluation of the use of PET/CT in the staging, prognostication, and recurrence prediction for GI malignancies.

Postoperative surveillance of pancreatic cancer patients

BACKGROUND

The aim of this study is to collect the best available evidence for diagnostic modalities, frequency, and duration of surveillance after resection for pancreatic ductal adenocarcinoma (PDAC).

METHODS

PDAC guidelines published after 2015 were collected. Furthermore, a systematic search of the literature on postoperative surveillance was performed in PubMed and Embase from 2000 to 2019. Articles comparing different diagnostic modalities and frequencies of postoperative surveillance in PDAC patients with regard to survival, quality of life, morbidity and cost-effectiveness were selected.

RESULTS

The literature search resulted in 570 articles. A total of seven guidelines and twelve original clinical studies were eventually evaluated. PDAC guidelines increasingly recommend a combination of tumor marker testing and computed tomography (CT) imaging every three to six months during the first two years after resection. These guidelines are, however, based on expert opinion and other low-level evidence. Prospective studies comparing different surveillance strategies are lacking. According to recent studies, surveillance with tumor markers and imaging at regular intervals results in the detection of PDAC recurrence before the onset of symptoms and more frequent administration of further therapy, such as chemotherapy or radiotherapy.

CONCLUSION

Current evidence for recurrence-focused surveillance after PDAC resection is limited and contradictory. Consequently, recommendations on surveillance are conflicting. To define the clinical merit of recurrence-focused surveillance, patients who are most likely to benefit from early detection and treatment of PDAC recurrence need to be identified. To this purpose, well-designed prospective studies are needed, accounting for both economical and psychosocial implications of surveillance.

Prognostic values of 18F-FDG PET/CT metabolic parameters and clinical figures in locally advanced pancreatic cancer underwent chemotherapy combined with stereotactic body radiation therapy

Stereotactic body radiation therapy (SBRT) has emerged to be a preference treatment for locally advanced pancreatic cancer (LAPC) patients. In this study, we aimed to investigate the prognostic roles of F-FDG PET/CT metabolic parameters and clinical figures in LAPC patients underwent chemo-SBRT combined therapy.During January 2013 to January 2017, 23 LAPC patients who underwent F-FDG PET/CT within 2 weeks before treatment were recruited and retrospectively analyzed. Maximum standardized uptake values (SUVmax), SUVmean, metabolic tumor volume (MTV), total lesion glycolysis (TLG), chemoradiotherapy (CRT) sequence, and relevant clinical figures were grouped upon the median values, then analyzed by Kaplan-Meier method and Cox proportional hazard models for their prognostic evaluation.The median overall survival (OS) and progression-free survival (PFS) of all patients were 16.7 months and 11.3 months, respectively. According to the statistic results, the longest diameter of tumor (LDT), MTV, TLG, and CRT sequence were associated with OS (all P <.05). Among which, LDT and MTV were proved to be the independent prognostic factors for OS (hazard ratio [HR]: 3.437, 3.015, both P <.05). Additionally, LDT and CRT sequence were found associated with PFS (both P <.05), and CRT sequence was the independent prognostic factor for PFS in chemo-SBRT treated LAPC patients (HR: 0.130, P <.05).For LAPC patients received chemotherapy and SBRT combined therapy, MTV and LDT showed independent prognostic values for OS. Meanwhile, CRT sequence was an independent PFS prediction factor.

A Review of Pancreatic Cancer: Epidemiology, Genetics, Screening, and Management

Pancreatic cancer ranks among the causes of cancer-related deaths. The average size of pancreatic cancer during diagnosis is about 31 mm and has not changed significantly over the past 30 years. Poor early diagnosis of a tumour has been attributed to the late-presenting symptoms. Over the years, improvement in the diagnosis of pancreatic cancer has been observed, and this can be linked to advancement in imaging techniques as well as the increasing knowledge of cancer history and genetics. Magnetic Resonance Imaging, Endoscopic Ultrasound, and Computer Topography are the approved imaging modalities utilised in the diagnosing of pancreatic cancer. Over the years, the management of patients with pancreatic cancer has seen remarkable improvement as reliable techniques can now be harnessed and implemented in determining the resectability of cancer. However, only about 10% of pancreatic adenocarcinomas are resectable at the time of diagnosis and will highly benefit from a microscopic margin-negative surgical resection. Overall, the failure of early tumour identification will result in considerable morbidity and mortality.

Clinical and prognostic value of 18F-FDG-PET/CT in restaging of pancreatic cancer

AIM

The aim of this retrospective multicentre study was to evaluate the clinical and prognostic effect of fluorine-18-fluorodeoxyglucose (F-FDG)-PET/computed tomography (CT) in the restaging process of pancreatic cancer (PC).

MATERIALS AND METHODS

Data from patients treated for primary PC, who underwent F-FDG-PET/CT for suspicious of disease progression, were collected. Accuracy was assessed employing conventional diagnostic procedures, multidisciplinary team case notes, further F-FDG-PET/CT scans and/or follow-up. Receiver operating characteristic curve and likelihood ratio (LR+/-) analyses were used for completion of accuracy definition. Progression-free survival (PFS) and overall survival were assessed by using Kaplan-Meier method. The Cox proportional hazards model was used to identify predictors of outcome.

RESULTS

Fifty-two patients (33 males and 19 females, with mean age of 59 years and range: 42-78 years) with PC were finally included in our study. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of F-FDG-PET were 85, 84, 90, 76, and 84%, respectively. Area under the curve was 0.84 (95% confidence intervals: 0.72-0.96; P<0.05). LR+ and LR- were 5.3 and 0.17, respectively. F-FDG-PET/CT revealed new metastatic foci in 5/52 patients (10%) and excluded suspicious lesions in 11/52 (21%). Analysis of PFS revealed F-FDG-PET/CT positivity to be associated with a worse cumulative survival rate over a 6 and 12-month period in comparison with F-FDG-PET/CT negativity (6-month PFS 95 vs. 67%, P<0.05; 12-month PFS 81 vs. 29%, P<0.05). A negative F-FDG-PET/CT result was associated with a significantly longer overall survival than a positive one (70 vs. 26% after 2 years, P<0.05). In addition, a positive F-FDG-PET/CT scan result and an maximum standardized uptake value (SUVmax) value more than 6 were significantly associated with an increased risk of disease progression (PET positivity hazard ratio=3.9, P=0.01; SUVmax>6 h=4.2, P=0.02) and death (PET positivity hazard ratio=3.5, P=0.02; SUVmax>6 h=3.7, P=0.01).

CONCLUSION

F-FDG-PET/CT showed high diagnostic accuracy for restaging process of PC, proving also its potential value in predicting clinical outcome after primary treatment.

Systematic review on the role of serum tumor markers in the detection of recurrent pancreatic cancer

BACKGROUND

Biomarker testing can be helpful to monitor disease progression after resection of pancreatic cancer. This systematic review aims to give an overview of the literature on the diagnostic value of serum tumor markers for the detection of recurrent pancreatic cancer during follow-up.

METHODS

A systematic search was performed to 2 October 2017. All studies reporting on the diagnostic value of postoperatively measured serum biomarkers for the detection of pancreatic cancer recurrence were included. Data on diagnostic accuracy of tumor markers were extracted. Forest plots and pooled values of sensitivity and specificity were calculated.

RESULTS

Four articles described test results of CA 19-9. A pooled sensitivity and specificity of respectively 0.73 (95% CI 0.66-0.80) and 0.83 (95% CI 0.73-0.91) were calculated. One article reported on CEA, showing a sensitivity of 50% and specificity of 65%. No other serum tumor markers were discussed for surveillance purposes in the current literature.

CONCLUSION

Although testing of serum CA 19-9 has considerable limitations, CA 19-9 remains the most used serum tumor marker for surveillance after surgical resection of pancreatic cancer. Further studies are needed to assess the role of serum tumor marker testing in the detection of recurrent pancreatic cancer and to optimize surveillance strategies.

Imaging findings of recurrent pancreatic cancer following resection

Pancreatic cancer is a challenging malignancy to treat, largely due to aggressive regional involvement, early systemic dissemination, high recurrence rate, and subsequent low patient survival. Generally, 15-20% of newly diagnosed pancreatic cancers are candidates for possible curative resection. Eighty percent of these patients, however, will experience locoregional or distant recurrence in first 2 years. Although there is no strong evidence-based guideline for optimal surveillance after pancreatic cancer resection, careful comparison of surveillance follow-up multi-detector CT (MDCT) studies with a postoperative baseline MDCT examination aids detection of early recurrent pancreatic cancer. In this review article, we describe imaging findings suggestive of recurrent pancreatic cancer and review routine and alternative imaging options.

Application of positron emission tomography-computed tomography in the diagnosis of pulmonary ground-glass nodules

The aim of the present study was to investigate the value of positron emission tomography-computed tomography (PET-CT) using ¹⁸F-fluorodeoxyglucose in the clinical diagnosis of pulmonary ground-glass nodule. In total, 54 patients with pulmonary GGN that were identified by PET-CT examination were selected and confirmed by pathology and clinical diagnosis in hospital between April 2014 and April 2015. The association between PET-CT findings and pathology, and the value of PET-CT were then evaluated. In the 54 patients, solitary pulmonary GGN with a nodule diameter of between 0.6 and 2.0 cm were detected. Amongst them, the PET-CT examination of 42 patients revealed hyper metabolic nodules, and were all mixed GGN type nodules with a diameter >1 cm. The PET-CT examination of the remaining 12 patients demonstrated no evidence of metabolic abnormalities and the nodules in these patients were pure or mixed GGN with a diameter <1 cm (except 2 cases with a diameter ≥1 cm). Furthermore, the diagnoses for all patients were pathologically confirmed by CT-guided needle biopsy or thoracoscopic surgical resection. Amongst them, there were 41 cases of lung adenocarcinoma, 4 cases of fungal infection, 7 cases of inflammation and 2 cases of adenomatoid hyperplasia. Additionally, PET-CT has a lower detection rate for smaller GGN exhibits no clear advantage for pure GGN, but has a higher detection rate for larger GGN. In conclusion, to a certain extent, PET-CT makes up for the shortcomings of traditional imaging and has some clinical value for the diagnosis of GGN.

Use of Nanoparticle Contrast Agents for Cell Tracking with Computed Tomography

Efforts to develop novel cell-based therapies originated with the first bone marrow transplant on a leukemia patient in 1956. Preclinical and clinical examples of cell-based treatment strategies have shown promising results across many disciplines in medicine, with recent advances in immune cell therapies for cancer producing remarkable response rates, even in patients with multiple treatment failures. However, cell-based therapies suffer from inconsistent outcomes, motivating the search for tools that allow monitoring of cell delivery and behavior in vivo. Noninvasive cell imaging techniques, also known as cell tracking, have been developed to address this issue. These tools can allow real-time, quantitative, and long-term monitoring of transplanted cells in the recipient, providing insight on cell migration, distribution, viability, differentiation, and fate, all of which play crucial roles in treatment efficacy. Understanding these parameters allows the optimization of cell choice, delivery route, and dosage for therapy and advances cell-based therapy for specific clinical uses. To date, most cell tracking work has centered on imaging modalities such as MRI, radionuclide imaging, and optical imaging. However, X-ray computed tomography (CT) is an emerging method for cell tracking that has several strengths such as high spatial and temporal resolution, and excellent quantitative capabilities. The advantages of CT for cell tracking are enhanced by its wide availability and cost effectiveness, allowing CT to become one of the most popular clinical imaging modalities and a key asset in disease diagnosis. In this review, we will discuss recent advances in cell tracking methods using X-ray CT in various applications, in addition to predictions on how the field will progress.