The clinical usefulness of 18-fluorodeoxyglucose positron emission tomography in the differential diagnosis, staging, and response evaluation after concurrent chemoradiotherapy for pancreatic cancer

Clinical Outcomes of Proton Beam Therapy for Unresectable Locally Advanced Pancreatic Cancer: A Single-Center Retrospective Study

Purpose

We retrospectively researched the treatment outcome of proton beam therapy (PBT) and assessed its efficacy for inoperable locally advanced pancreatic cancer (LAPC) at our institution.

Methods and Materials

Fifty-four patients (28 men and 26 women, median age 67 years ranging from 40-88 years) were diagnosed with unresectable stage III LAPC and administered PBT from April 2009 to March 2020. Patients who could not complete PBT, had new distant metastases during the treatment, or did not have enough follow-up time were excluded from this study. All patients were clinically staged based on the International Union of Cancer TNM staging system (eighth edition) using computed tomography, magnetic resonance imaging, and positron emission tomography and were diagnosed as stage III (histologic type: 18 patients with adenocarcinoma and 36 clinically diagnosed patients). PBT was performed using the passive method, with a median total dose of 67.5 GyE (range, 50-77 GyE/25-35 fractions).Chemotherapy was used in combination during PBT in 46 patients (85.2%). Overall survival (OS), local progression-free survival (LPFS), progression-free survival, and median OS time were analyzed by Kaplan-Meier and log-rank tests. Univariate and multivariate analyses were performed for the following factors: maximum standardized uptake value (SUVmax), Eastern Cooperative Group performance status (PS), tumor site, total irradiation dose, concurrent chemotherapy, and primary tumor site. Cutoff values for SUVmax and tumor diameter were estimated using receiver operating characteristic curves and the area under the curve based on OS. Multivariate analysis was evaluated using the Cox proportional hazards models. Adverse events were evaluated using the National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0.

Results

The median observation period was 17.4 months, ranging from 4.0 to 89.7 months. The median tumor diameter was 36.5 mm, ranging from 15 to 90 mm, the median SUVmax was 5.85 (range, 2.1-27.6), and their cutoff values were estimated to be 37 mm and 4.8 mm, respectively. The 1- and 2-year OS was 77.8% and 35.2%, respectively, with a median OS time of 18.2 months, and only one patient survived >5 years. Twelve patients (22.2%) developed local recurrence, and 1- and 2-year LPFS rates were 89.7% and 74.5%, respectively; progression-free survival at 1 year was 58.8%. The PS score, tumor site, and irradiation dose were the prognostic factors related to OS that showed a significant difference. On the other hand, there was a significant difference in factors involved in LPFS, at 96.7%/77.9% in the first year and 86.6%/54.4% in the second year in the groups with tumor dose ≥67.5 GyE and <67.5 GyE, respectively (P = .015). Treatment-related acute toxicities were neutropenia (grade 1/2/3 at 3.7%/11.1%/31.5%, respectively), leukopenia (grade 1/2/3 at 1.8%/7.4%/20.4%, respectively), and thrombocytopenia (grade 1/2 at 1.8%/7.4%, respectively), whereas the late effects including peptic ulcer were captured only grade 2+. The late adverse events of grade 3 or higher were not observed.

Conclusions

PBT achieving 67.5 Gy combined with standard chemotherapy showed excellent local control for unresectable LAPC. Total irradiation dose, tumor site, and PS score at an initial diagnosis could be important prognostic factors. In this study, the dose-effect relationship was found, so an increase in dose should be considered to improve prognosis.

Differentially expressed genes associated with high metabolic tumor volume served as diagnostic markers and potential therapeutic targets for pancreatic cancer

BACKGROUND

The lack of distinct biomarkers for pancreatic cancer is a major cause of early-stage detection difficulty. The pancreatic cancer patient group with high metabolic tumor volume (MTV), one of the values measured from positron emission tomography-a confirmatory method and standard care for pancreatic cancer, showed a poorer prognosis than those with low MTV. Therefore, MTV-associated differentially expressed genes (DEGs) may be candidates for distinctive markers for pancreatic cancer. This study aimed to evaluate the possibility of MTV-related DEGs as markers or therapeutic targets for pancreatic cancer.

METHODS

Tumor tissues and their normal counterparts were obtained from patients undergoing preoperative 18F-FDG PET/CT. The tissues were classified into MTV-low and MTV-high groups (7 for each) based on the MTV2.5 value of 4.5 (MTV-low: MTV2.5 < 4.5, MTV-high: MTV2.5 ≥ 4.5). Gene expression fold change was first calculated in cancer tissue compared to its normal counter and then compared between low and high MTV groups to obtain significant DEGs. To assess the suitability of the DEGs for clinical application, the correlation of the DEGs with tumor grades and clinical outcomes was analyzed in TCGA-PAAD, a large dataset without MTV information.

RESULTS

Total RNA-sequencing (MTV RNA-Seq) revealed that 44 genes were upregulated and 56 were downregulated in the high MTV group. We selected the 29 genes matching MTV RNA-seq patterns in the TCGA-PAAD dataset, a large clinical dataset without MTV information, as MTV-associated genes (MAGs). In the analysis with the TCGA dataset, MAGs were significantly associated with patient survival, treatment outcomes, TCGA-PAAD-suggested markers, and CEACAM family proteins. Some MAGs showed an inverse correlation with miRNAs and were confirmed to be differentially expressed between normal and cancerous pancreatic tissues. Overexpression of KIF11 and RCC1 and underexpression of ADCY1 and SDK1 were detected in ~ 60% of grade 2 pancreatic cancer patients and associated with ~ 60% mortality in stages I and II.

CONCLUSIONS

MAGs may serve as diagnostic markers and miRNA therapeutic targets for pancreatic cancer. Among the MAGs, KIF11, RCC1, ADCY, and SDK1 may be early diagnostic markers.

Prognostic Strength of CA 19-9, Demographic Parameters, and Maximum Standardized Uptake Value of Baseline 18F-FDG PET/CT in Treatment-naïve Patients with Pancreatic Carcinoma

Aim and Background

The aim of this study was to evaluate the prognostic value of imaging-based variables and tumor marker in predicting the progression-free survival (PFS) in treatment-naïve pancreatic cancer (PC) using baseline 18-fluorodeoxyglucose (18FDG) positron emission tomography/computed tomography (PET/CT).

Materials and Methods

This retro-prospective study was conducted at PET/CT imaging facility of JCIA health-care facility of Pakistan. Total 68 patients with PCs were retrospectively included who had 18FDG PET/CT for staging from March 2017 to December 2020. Thirty-two patients had unresectable Stage IV disease on baseline imaging while the remaining 36 underwent Whipple's procedure and both categories were followed by chemotherapy with/without immunotherapy. These patients were followed for a median period of 18 months (1-62 months) for PFS. Logistic regression analysis and receiver operating characteristic (ROC) analysis were used for independent predictors of patients' demographics, tumor characteristics, CA 19-9, and maximum standardized uptake value (SUVmax) in PFS. Kaplan-Meier's survival curves were analyzed to measure PFS using ROC-derived significant cutoff values of CA 19-9 and SUVmax.

Results

Median PFS was 18 months (11-45) with 60% (41/68) patients were either died or labelled having metabolic progressive disease (MPD. Using logistic regression analysis, significant correlations were found for Stage IV disease and pancreatic body/tail tumor with disease progression (odd ratio: 7.535 and 4.803, respectively; P < 0.05). Gender, obesity, histological tumor type, and 18FDG-avid regional nodes did not show a significant impact on PFS. On ROC analysis, SUVmax >5.3 of primary tumor and baseline CA 19-9 >197 U/ml were found to have a significant negative correlation with PFS (area under the curve: 0.827 and 0.911, respectively; P < 0.0001) and no association of age and primary tumor size in PFS. Significantly, shorter PFS was found using ROC-derived cutoff values of SUVmax >5.3 versus ≤5.3 of primary tumor (mean and 95% confidence interval [CI]: 16.7 vs. 48.5 and 10-23 vs. 41-56; log-rank = 25.014; P < 0.0001) and baseline CA 19-9 >197 versus ≤197 U/ml (mean and 95% CI: 11.8 vs. 46.9 and 7-16 vs. 39-55; log-rank = 38.217; P < 0.0001).

Conclusion

SUVmax >5.3 of primary tumor and baseline CA 19-9 >197 U/ml were found to have a significant negative correlation with PFS in treatment-naïve PC patients. Among demographics, only Stage IV disease and pancreatic tail and body tumors were found to have a negative association with disease progression.

Prognostic Evaluation Based on Dual-Time 18F-FDG PET/CT Radiomics Features in Patients with Locally Advanced Pancreatic Cancer Treated by Stereotactic Body Radiation Therapy

Background

18F-FDG PET/CT is widely used in the prognosis evaluation of tumor patients. The radiomics features can provide additional information for clinical prognostic assessment.

Purpose

Purpose is to explore the prognostic value of radiomics features from dual-time 18F-FDG PET/CT images for locally advanced pancreatic cancer (LAPC) patients treated with stereotactic body radiation therapy (SBRT).

Materials and Methods

This retrospective study included 70 LAPC patients who received early and delayed 18F-FDG PET/CT scans before SBRT treatment. A total of 1188 quantitative imaging features were extracted from dual-time PET/CT images. To avoid overfitting, the univariate analysis and elastic net were used to obtain a sparse set of image features that were applied to develop a radiomics score (Rad-score). Then, the Harrell consistency index (C-index) was used to evaluate the prognosis model.

Results

The Rad-score from dual-time images contains six features, including intensity histogram, morphological, and texture features. In the validation cohort, the univariate analysis showed that the Rad-score was the independent prognostic factor (p < 0.001, hazard ratio [HR]: 3.2). And in the multivariate analysis, the Rad-score was the only prognostic factor (p < 0.01, HR: 4.1) that was significantly associated with the overall survival (OS) of patients. In addition, according to cross-validation, the C-index of the prognosis model based on the Rad-score from dual-time images is better than the early and delayed images (0.720 vs. 0.683 vs. 0.583).

Conclusion

The Rad-score based on dual-time 18F-FDG PET/CT images is a promising noninvasive method with better prognostic value.

Imaging Assessment of Pancreatic Cancer Resectability After Neoadjuvant Therapy: AJR Expert Panel Narrative Review

Despite important innovations in the treatment of pancreatic ductal adenocarcinoma (PDAC), PDAC remains a disease with poor prognosis and high mortality. A key area for potential improvement in the management of PDAC, aside from earlier detection in patients with treatable disease, is the improved ability of imaging techniques to differentiate treatment response after neoadjuvant therapy (NAT) from worsening disease. It is well established that current imaging techniques cannot reliably make this distinction. This narrative review provides an update on the imaging assessment of pancreatic cancer resectability after NAT. Current definitions of borderline resectable PDAC, as well as implications for determining likely patient benefit from NAT, are described. Challenges associated with PDAC pathologic evaluation and surgical decision making that are of relevance to radiologists are discussed. Also explored are the specific limitations of imaging in differentiating the response after NAT from stable or worsening disease, including issues relating to protocol optimization, tumor size assessment, vascular assessment, and liver metastasis detection. The roles of MRI as well as PET and/or hybrid imaging are considered. Finally, a short PDAC reporting template is provided for use after NAT. The highlighted methods seek to improve radiologists' assessment of PDAC treatment response after NAT.

The Role of Positron Emission Tomography/Computed Tomography (PET/CT) for Staging and Disease Response Assessment in Localized and Locally Advanced Pancreatic Cancer

Pancreatic Cancer (PC) has a poor prognosis, with a 5-year survival rate of only 9%. Even after radical surgical procedures, PC patients have poor survival rates, with a high chance of relapse (70-80%). Imaging is involved in all aspects of the clinical management of PC, including detection and characterization of primary tumors and their resectability, assessment of vascular, perineural and lymphatic invasion and detection of distant metastases. The role of Positron Emission Tomography/Computed Tomography (PET/CT) in detecting PC is still controversial, with the international guidelines not recommending its routine use. However, in resectable PC, PET/CT may play a role in assessing PC stage and grade and potential resectability after neoadjuvant treatment. Quantitative image analysis (radiomics) and new PET/CT radiotracers account for future developments in metabolic imaging and may further improve the relevance of this technique in several aspects of PC. In the present review, the current state of the art and future directions of PET/CT in resectable PC are presented.

Impact of PET/MRI in the Treatment of Pancreatic Adenocarcinoma: a Retrospective Cohort Study

PURPOSE

Imaging is central to the diagnosis and management of Pancreatic Ductal Adenocarcinoma (PDAC). This study evaluated if positron emission tomography (PET)/magnetic resonance imaging (MRI) elicited treatment modifications in PDAC when compared to standard of care imaging (SCI).

PROCEDURES

This retrospective study included consecutive patients with PDAC who underwent 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]F-FDG) PET/MRI and SCI from May 2017 to January 2019. SCI included abdominal computed tomography (CT), MRI, and/or PET/CT. For patients who had more than one pair of PET/MRI and SCI, each management decision was independently evaluated. Treatment strategies based on each modality were extracted from electronic medical records. Follow-up was evaluated until January 2020.

RESULTS

Twenty-five patients underwent 37 PET/MRI's, mean age was 65 ± 9 years and 13 (13/25, 52 %) were men. 49 % (18/37, 95 % CI 33-64 %) of the PET/MRI scans changed clinical management. Whether the SCI included a PET/CT or not did not significantly modify the probability of management change (OR = 0.9, 95 % CI 0.2-4, p = 1). One hundred percent (33/33) of the available follow-up data confirmed PET/MRI findings.

CONCLUSIONS

PET/MRI significantly changed PDAC management, consistently across the different SCI modalities it was compared to. These findings suggest a role for PET/MRI in the management of PDAC.

Current status of targeted microbubbles in diagnostic molecular imaging of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is often associated with a poor prognosis due to silent onset, resistance to therapies, and rapid spreading. Most patients are ineligible for curable surgery as they present with advanced disease at the time of diagnosis. Present diagnostic methods relying on anatomical changes have various limitations including difficulty to discriminate between benign and malignant conditions, invasiveness, the ambiguity of imaging results, or the inability to detect molecular biomarkers of PDAC initiation and progression. Therefore, new imaging technologies with high sensitivity and specificity are critically needed for accurately detecting PDAC and noninvasively characterizing molecular features driving its pathogenesis. Contrast enhanced targeted ultrasound (CETUS) is an upcoming molecular imaging modality that specifically addresses these issues. Unlike anatomical imaging modalities such as CT and MRI, molecular imaging using CETUS is promising for early and accurate detection of PDAC. The use of molecularly targeted microbubbles that bind to neovascular targets can enhance the ultrasound signal specifically from malignant PDAC tissues. This review discusses the current state of diagnostic imaging modalities for pancreatic cancer and places a special focus on ultrasound targeted-microbubble technology together with its clinical translatability for PDAC detection.

Prognostic value of 18FDG PET/CT volumetric parameters in the survival prediction of patients with pancreatic cancer

PURPOSE

To investigate the value of 18 FDG PET/CT volumetric parameters in the prediction of overall survival (OS) in patients with pancreatic cancer and also, assess their independence relative to well-established clinico-pathological variables.

METHODS

We conducted a retrospective analysis of patients with a confirmed diagnosis of pancreatic cancer who underwent 18 FDG PET/CT. The tumour maximum standardised uptake value (SUVmax) in addition to SUVmean, metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were calculated. The prognostic value of 18 FDG PET/CT and clinico-pathological parameters for OS were assessed using univariate and multivariable analyses.

RESULTS

A sum of 89 patients were analysed in this study. Median survival for patients categorised as having high TLG (≥55) and low TLG (<55) was 18 vs 5 months (p < 0.001). Similarly, the respective high vs low SUVmean, MTV and SUVmax were 18 vs 6 months (p = 0.001), 16 vs 6 months (p = 0.002) and 18 vs 6 months (p = 0.001). Univariate analysis showed SUVmax, SUVmean, MTV, TLG, tumour size, tumour differentiation and presence of distant metastasis as prognostic factors for OS. On multivariable analysis, TLG (HR 2.0, 95% CI 1.26-3.18, p = 0.004) and the presence of distant metastasis (HR 3.37, 95% CI 1.97-5.77, p < 0.001) emerged as independent prognostic factors. Subgroup analysis identified TLG as the only significant PET metric after adjusting for the presence of distant metastasis.

CONCLUSIONS

18 FDG PET/CT is a useful tool in the preoperative evaluation of patients with pancreatic cancer. Tumour TLG offer an independent prognostic value in both potentially operable and metastatic disease settings.

Evaluation of response using FDG-PET/CT and diffusion weighted MRI after radiochemotherapy of pancreatic cancer: a non-randomized, monocentric phase II clinical trial-PaCa-DD-041 (Eudra-CT 2009-011968-11)

Background

Pancreatic cancer is a devastating disease with a 5-year survival rate of 20–25%. As approximately only 20% of patients diagnosed with pancreatic cancer are initially staged as resectable, it is necessary to evaluate new therapeutic approaches. Hence, neoadjuvant (radio)chemotherapy is a promising therapeutic option, especially in patients with a borderline resectable tumor. The aim of this non-randomized, monocentric, prospective, phase II clinical study was to assess the prognostic value of functional imaging techniques, i.e., [¹⁸F]2-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (FDG-PET/CT) and diffusion weighted magnetic resonance imaging (DW-MRI), prior to and during neoadjuvant radiochemotherapy.

Methods

Patients with histologically proven resectable, borderline resectable or unresectable non-metastatic pancreatic adenocarcinoma received induction chemotherapy followed by neoadjuvant radiochemotherapy. Patients underwent FDG-PET/CT and DW-MRI including T1- and T2-weighted sequences prior to and after neoadjuvant chemotherapy as well as following induction radiochemotherapy. The primary endpoint was the evaluation of the response as quantified by the standardized uptake value (SUV) measured with FDG-PET. Response to treatment was evaluated by FDG-PET and DW-MRI during and after the neoadjuvant course. Morphologic staging was performed using contrast-enhanced CT and contrast-enhanced MRI to decide inclusion of patients and resectability after neoadjuvant therapy. In those patients undergoing subsequent surgery, imaging findings were correlated with those of the pathologic resection specimen.

Results

A total of 25 patients were enrolled in the study. The response rate measured by FDG-PET was 85% with a statistically significant decrease of the maximal SUV (SUV_max) during therapy (p < 0.001). Using the mean apparent diffusion coefficient (ADC), response was not detectable with DW-MRI. After neoadjuvant treatment 16 patients underwent surgery. In 12 (48%) patients tumor resection could be performed. The median overall survival of all patients was 25 months (range: 7–38 months).

Conclusion

Based on these limited patient numbers, it was possible to show that this trial design is feasible and that the neoadjuvant therapy regime was well tolerated. FDG-PET/CT may be a reliable method to evaluate response to the combined therapy. In contrast, when evaluating the response using mean ADC, DW-MRI did not show conclusive results.

Electronic supplementary material

The online version of this article (10.1007/s00066-020-01654-4) contains supplementary material, which is available to authorized users.

Prognostic value of 18F-FDG PET /CT metabolic parameters in patients with locally advanced pancreatic Cancer treated with stereotactic body radiation therapy

Background

¹⁸F-FDG PET/CT metabolic parameters have been applied as prognostic factors in multi-malignancies. However, the role in locally advanced pancreatic cancer (LAPC) was not confirmed. In this study, we investigated the prognostic value of ¹⁸F-FDG PET/CT metabolic parameters in LAPC patients treated with stereotactic body radiation therapy (SBRT).

Methods

Seventy three LAPC patients who received SBRT therapy and pre-treatment ¹⁸F-FDG PET/CT imaging from January 2012 to January 2016 were included in this retrospective study. The study aim was to evaluate the relationship between metabolic parameters with clinical factors, and the value of metabolic parameters in the prognosis of LAPC. The median of parameters was set as the cut-off value for statistical analysis. Univariate survival analysis was performed by the Kaplan Meier method and log-rank test, and multivariate analysis was carried out by a Cox proportional hazards model.

Results

Patients with lymph node metastasis or longer tumor diameters were associated with higher TLG (P < 0.05). Univariate analysis showed MTV, TLG, radiotherapy dose and chemotherapy were significantly associated with disease progression-free survival (PFS) and overall survival (OS) (P < 0.05). Lymph node metastasis and tumor longest diameter were associated with OS. Multivariate analysis demonstrated TLG, radiotherapy dose, and chemotherapy were independent factors of PFS and OS (HR: 2.307, 0.591, 0.572 and 2.145, 0.480, 0.471, P < 0.05).

Conclusions

TLG was found to be the independent prognostic factor of OS and PFS. Among clinical factors, radiotherapy dose and chemotherapy were independent prognostic factors of OS and PFS.

The Role of PET/CT in the Imaging of Pancreatic Neoplasms

Pancreas cancer is a complex disease and its prognosis is related to the origin of the tumor cell as well as the stage of disease at the time of diagnosis. Pancreatic adenocarcinomas derive from the exocrine pancreas and are the fourth leading cause of cancer-related deaths in the United States, while well-differentiated pancreatic neuroendocrine tumors (pNETs) derived from the endocrine part of the pancreas are rare and characterized by a slow growth and good life expectancy. Surgery is the only curative treatment approach, and an accurate assessment of resectability is of paramount importance in order to avoid futile procedures. The role of molecular imaging with positron emission tomography and computed tomography ranges from indispensable for pNETs to controversial for certain scenarios in pancreatic adenocarcinomas. This review article aims to overview molecular pancreatic imaging.

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.

18F-FDG PET/CT in pancreatic adenocarcinoma: A role at initial imaging staging?

Pancreatic ductal adenocarcinoma represents 90% of all pancreatic tumors. The only hope for prolonged survival in patients with this condition still remains surgery with complete R0 resection. Initial imaging has a pivotal role to identify patients who are eligible to curative surgery and those who may benefit of neoadjuvant chemotherapy. This review provides an analysis of the recent literature on 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in pancreatic adenocarcinoma. Performances of FDG PET in the detection of lymph node involvement and metastatic spread at initial staging and those in the assessment of response to treatment are described.

Combined morphologic and metabolic pipeline for Positron emission tomography/computed tomography based radiotherapy response evaluation in locally advanced pancreatic adenocarcinoma

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A novel morphologic and metabolic combined pipeline for PA response evaluation.

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The derived metric outperformed traditional imaging metrics in risk stratification.

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May serve as a new image biomarker to characterize heterogeneous tumor response.

Background and purpose

Adaptive radiation planning for pancreatic adenocarcinoma (PA) relies on accurate treatment response assessment, while traditional response evaluation criteria inefficiently characterize tumors with complex morphological features or intrinsically low metabolism. To better assess treatment response of PA, we quantify and compare regional morphological and metabolic features of the 3D pre- and post-radiation therapy (RT) tumor models.

Materials and methods

Thirty-one PA patients with pre and post-RT Positron emission tomography/computed tomography (PET/CT) scans were evaluated. 3D meshes of pre- and post-RT tumors were generated and registered to establish vertex-wise correspondence. To assess tumor response, Mahalanobis distances (M_dist|_Fusion) between pre- and post-RT tumor surfaces with anatomic and metabolic fused vectors were calculated for each patient. M_dist|_Fusion was evaluated by overall survival (OS) prediction and survival risk classification. As a comparison, the same analyses were conducted on traditional imaging/physiological predictors, and distances measurements based on metabolic and morphological features only.

Results

Among all the imaging/physiological parameters, M_dist|_Fusion was shown to be the best predictor of OS (HR = 0.52, p = 0.008), while other parameters failed to reach significance. Moreover, M_dist|_Fusion outperformed traditional morphologic and metabolic measurements in patient risk stratification, either alone (HR = 11.51, p < 0.001) or combined with age (HR = 9.04, p < 0.001).

Conclusions

We introduced a PET/CT-based novel morphologic and metabolic pipeline for response evaluation in locally advanced PA. The fused M_dist|_Fusion outperformed traditional morphologic, metabolic, and physiological measurements in OS prediction and risk stratification. The novel fusion model may serve as a new imaging-marker to more accurately characterize the heterogeneous tumor RT response.

PET/MR Imaging of the Pancreas

PET/MR imaging has the potential to markedly alter pancreatic care in both the malignant, and premalignant states with the ability to perform robust, high-resolution, quantitative molecular imaging. The ability of PET/MR imaging to monitor disease processes, potentially correct for motion in the upper abdomen, and provide novel biomarkers that may be a combination of MR imaging and PET biomarkers, offers a unique, precise interrogation of the pancreatic milieu going forward.

Diagnosis and Detection of Pancreatic Cancer

Computed tomography is the first-line imaging modality for suspected pancreatic cancer. Magnetic resonance cholangiopancreatography is a second-line modality for suspected pancreatic cancer and is usually reserved for equivocal cases. Both computed tomography and MR are highly sensitive in the detection of pancreatic cancer, with up to 96% and 93.5% sensitivity, respectively. Computed tomography is superior to MR in the assessment of tumor resectability, with accuracy rates of up to 86.8% and 78.9%, respectively. Close attention to secondary signs of pancreatic cancer, such as pancreatic duct dilatation, abrupt pancreatic duct caliber change, and parenchymal atrophy, are critical in the diagnosis of pancreatic cancer. Emerging techniques such as radiomics and molecular imaging have the potential of identifying malignant precursors and lead to earlier disease diagnosis. The results of these promising techniques need to be validated in larger clinical studies.

PET-based Treatment Response Assessment for Neoadjuvant Chemoradiation in Pancreatic Adenocarcinoma: An Exploratory Study

PURPOSE: Performance of anatomical metrics of Response Evaluation Criteria in Solid Tumors (RECIST1.1) versus Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST1.0) for neoadjuvant chemoradiation (nCR) of pancreatic adenocarcinoma was evaluated based on the pathological treatment response (PTR) data. METHODS AND MATERIALS: The pre- and post-nCR CT and PET data for 14 patients with resectable or borderline resectable pancreatic head adenocarcinoma treated with nCR followed by surgery were retrospectively analyzed. These data were compared with the PTR which were graded according to tumor cell destruction (cellularity), with Grade 0, 1, 2 or 3 (G0, G1, G2 or G3) for complete, moderate, minimal and poor responses, respectively. Maximum standardized uptake value (SUVmax) was defined using body-weight (SUVbw). PERCIST1.0 was defined using lean-body mass normalized SUV (SUVlb or SUL). RECIST1.1 was defined by contouring the whole pancreas head on the CT image. Pre- and post-SUL-peak and SUVmax, RECIST1.1 and PETRECIST1.0 were correlated with PTR using Pearson’s correlation coefficient test. RESULTS: The average mean and SD in SUL-peak for all patients analyzed were lower in post-nCR (3.63±1.06) compared to those at pre-nCR (4.29±0.89). Using PERCIST1.0, 62% of patients showed stable metabolic disease (SMD), 23% partial metabolic response (PMR), and 15% progressive metabolic disease (PMD). Using RECIST1.1, 85% of patients showed stable disease (SD), 8% partial response (PR), and 7% progressive diseases (PD). A poor insignificant correlation was established between PRT and PERECIST1.0 (r=0.121), whereas no correlation was seen with RECIST1.1. CONCLUSIONS: PERCIST1.0 appears to increase the chance of detecting patients with progressive disease compared to the conventional anatomical-based assessment of RECIST1.1. The integration of these additional radiographic metrics in assessing treatment response to nCR for pancreatic adenocarcinoma may provide a promising strategy to better select patients that are most suitable for therapeutic intensification.

18F-fluorodeoxyglucose positron emission tomography to indicate conversion surgery in patients with initially unresectable locally advanced pancreatic cancer

Objective

Advances in chemotherapy and chemoradiotherapy have enabled conversion of initially unresectable locally advanced (UR-LA) pancreatic adenocarcinoma (PDAC) to a resectable disease. However, definitive criteria for conversion surgery have not been established. We evaluated the potential of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) to indicate conversion surgery in patients with primary UR-LA PDAC.

Methods

Twenty consecutive patients with UR-LA PDAC underwent chemoradiation or chemotherapy followed by assessment with FDG-PET. We defined PET responders (standardized uptake value <3.0) with marked reduction (>80%) of carbohydrate antigen 19-9 as potential candidates for conversion surgery. Outcomes were compared with those of the patients with resectable (R; n = 94) and borderline resectable (BR; n = 37) PDAC.

Results

Eight of the 20 patients (40%) were considered PET responders with marked reduction of CA19-9 and received conversion surgery (UR-LAR) 3-9 months (median, 5 months) after the initiation of therapy. Complete resection (R0) was achieved in 7 of 8 patients (87.5%) with UR-LAR. There was no significant difference in R0 rates, morbidity, or mortality among the UR-LAR, R and BR groups. The overall survival (OS) curve was better in the UR-LAR group than in the group that did not receive surgery. There was no significant difference in OS between the UR-LAR and the R or BR groups.

Conclusions

FDG-PET could be a potential indicator for conversion surgery in patients with primary UR-LA PDAC and may help in selecting patients who qualify for complete surgical resection and have a promising prognosis.

Response assessment in pancreatic ductal adenocarcinoma: role of imaging

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive gastrointestinal (GI) malignancy with poor 5-year survival rate. Advances in surgical techniques and introduction of novel combination chemotherapy and radiation therapy regimens have necessitated the need for biomarkers for assessment of treatment response. Conventional imaging methods such as RECIST have been used for response evaluation in clinical trials particularly in patients with metastatic PDAC. However, the role of these approaches for assessing response to loco-regional and systemic therapies is limited due to complex morphological and histological nature of PDAC. Determination of tumor resectability after neoadjuvant therapy remains a challenge. This review article provides an overview of the challenges and limitations of response assessment in PDAC and reviews the current evidence for the utility of novel morphological and functional imaging tools in this disease.

The Role of 18F-FDG PET/CT and PET/MRI in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains a difficult disease to treat and continues to portend a poor prognosis, as most patients are unresectable at diagnosis. 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) combined with CT (PET/CT) has been a cornerstone in oncological imaging of different cancers; however, the role of PET/CT in PDAC is continually evolving and currently not well established. Studies have shown the potential of PET/CT in guiding the management of patients with PDAC, with possible added benefit over anatomic imaging with CT or MRI in certain scenarios. PET/CT may be useful in diagnosis, initial staging, treatment response assessment, differentiation of recurrent tumor from post-treatment fibrosis, and radiotherapy planning. Additionally, PET/CT may be a cost-effective modality due to upstaging of patients originally deemed as surgical candidates. Recently, the advent of simultaneous PET/MRI represents an exciting advancement in hybrid functional imaging with potential applications in the imaging of PDAC. The advantages of PET/MRI include simultaneous acquisition to improve registration of fusion images, lower radiation dose, superior soft tissue contrast, and availability of multiparametric imaging. Studies are underway to evaluate the utility of PET/MRI in PDAC, including in initial staging and treatment response assessment and to determine the subgroup of patients that will benefit from PET/MRI. Further studies are warranted in both PET/CR and PET/MRI to better understand the role of these modalities in PDAC.

Role of PET/CT in the Clinical Management of Locally Advanced Pancreatic Cancer

Aim

To evaluate the role of 18F-fluorodeoxyglucose (FDG) PET/CT in: a) the selection of patients with locally advanced pancreatic cancer for helical tomotherapy with concurrent chemotherapy (HTT-ChT); b) monitoring HTT-ChT treatment efficacy in comparison with contrast-enhanced CT (c.e.CT).

Methods

Forty-two consecutive patients with unresectable locally advanced pancreatic cancer referred for HTT-ChT were enrolled in the study. All patients were pretreated with induction ChT. Before the beginning of HTT-ChT treatment patients underwent diagnostic c.e.CT (CT0) and FDG PET/CT (PET/CT0) for staging. After staging, patients received HTT-ChT. Three months after the end of HTT-ChT a control c.e.CT (CT1) was done. FDG PET/CT (PET/CT1) was repeated only in patients with positive PET/CT0. PET/CT1 and CT1 were compared with baseline imaging results to assess treatment efficacy.

Results

In 31/42 cases (74%) PET/CT0 documented pathological uptake in pancreatic lesions, while in the remaining 11/42 cases it showed no uptake. In 7/42 (17%) patients, PET/CT0 also detected distant metastases, prompting a change in the therapeutic approach. Compared to PET/CT0, PET/CT1 (n = 18) documented 3 complete metabolic responses, 9 partial metabolic responses, 2 instances of stable metabolic disease, and 4 instances of progressive metabolic disease. In the same group of 18 patients, CT1 showed 0 complete responses, 3 partial responses, 8 instances of stable disease, and 7 instances of progressive disease compared to CT0. Concordance between PET/CT and CT response was seen in 33% of cases. In 50% of cases, PET/CT1 documented a response to therapy that was not evident on CT.

Conclusions

PET/CT influenced the treatment strategy by detecting distant metastases not documented by CT, thus accurately selecting patients for HTT-ChT after induction ChT. In monitoring treatment efficacy, PET/CT can detect a metabolic response to treatment not identified by CT.

Imaging-based biomarkers: Changes in the tumor interface of pancreatic ductal adenocarcinoma on computed tomography scans indicate response to cytotoxic therapy

BACKGROUND

The assessment of pancreatic ductal adenocarcinoma (PDAC) response to therapy remains challenging. The objective of this study was to investigate whether changes in the tumor/parenchyma interface are associated with response.

METHODS

Computed tomography (CT) scans before and after therapy were reviewed in 4 cohorts: cohort 1 (99 patients with stage I/II PDAC who received neoadjuvant chemoradiation and surgery); cohort 2 (86 patients with stage IV PDAC who received chemotherapy), cohort 3 (94 patients with stage I/II PDAC who received protocol‐based neoadjuvant gemcitabine chemoradiation), and cohort 4 (47 patients with stage I/II PDAC who received neoadjuvant chemoradiation and were prospectively followed in a registry). The tumor/parenchyma interface was visually classified as either a type I response (the interface remained or became well defined) or a type II response (the interface became poorly defined) after therapy. Consensus (cohorts 1‐3) and individual (cohort 4) visual scoring was performed. Changes in enhancement at the interface were quantified using a proprietary platform.

RESULTS

In cohort 1, type I responders had a greater probability of achieving a complete or near‐complete pathologic response (21% vs 0%; P = .01). For cohorts 1, 2, and 3, type I responders had significantly longer disease‐free and overall survival, independent of traditional covariates of outcomes and of baseline and normalized cancer antigen 19‐9 levels. In cohort 4, 2 senior radiologists achieved a κ value of 0.8, and the interface score was associated with overall survival. The quantitative method revealed high specificity and sensitivity in classifying patients as type I or type II responders (with an area under the receiver operating curve of 0.92 in cohort 1, 0.96 in cohort 2, and 0.89 in cohort 3).

CONCLUSIONS

Changes at the PDAC/parenchyma interface may serve as an early predictor of response to therapy. Cancer 2018;124:1701‐9. © 2018 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.

An imaging feature of pancreatic cancer is identified that indicates a response to cytotoxic therapies. This may be helpful as an early predictor of response for clinical trials and for deciding whether to change therapy.

89Zr-anti-γH2AX-TAT but not 18F-FDG Allows Early Monitoring of Response to Chemotherapy in a Mouse Model of Pancreatic Ductal Adenocarcinoma

Purpose: Late-stage, unresectable pancreatic ductal adenocarcinoma (PDAC) is largely resistant to chemotherapy and consequently has a very poor 5-year survival rate of <5%. The ability to assess the efficacy of a treatment soon after its initiation would enable rapid switching to potentially more effective therapies if the current treatment is found to be futile. We have evaluated the ability of the PET imaging agent, 89Zr-anti-γH2AX-TAT, to monitor DNA damage in response to fluorouracil (5-FU), gemcitabine, or capecitabine treatment in a mouse model of pancreatic cancer. We have also compared the utility of this approach against the standard clinical PET radiotracer, 18F-FDG.Experimental Design: C57BL/6 mice bearing subcutaneous pancreatic cancer (KPC; B8484) allografts were treated with 5-FU, gemcitabine, or capecitabine. Therapeutic response was monitored by PET and ex vivo biodistribution experiments using either 89Zr-anti-γH2AX-TAT or 18F-FDG as imaging agents. To further examine the effect of therapeutic response upon uptake of these imaging agents, IHC analysis of harvested tumor allograft tissue was also performed.Results: Accumulation of 89Zr-anti-γH2AX-TAT in the tumors of mice that received chemotherapy was higher compared with vehicle-treated mice and was shown to be specifically mediated by γH2AX. In contrast, 18F-FDG did not provide useful indications of therapeutic response.Conclusions:89Zr-anti-γH2AX-TAT has shown a superior ability to monitor early therapeutic responses to chemotherapy by PET imaging compared with 18F-FDG in an allograft model of PDAC in mice. Clin Cancer Res; 23(21); 6498-504. ©2017 AACR.

Influence of region-of-interest determination on measurement of signal-to-noise ratio in liver on PET images

OBJECTIVE

On ¹⁸F-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography (PET), signal-to-noise ratio in the liver (SNR_liver) is used as a metric to assess image quality. However, some regions-of-interest (ROIs) are used when measuring the SNR_liver. The purpose of this study is to examine the different ROIs and volumes of interest (VOIs) to obtain a reproducible SNR_liver.

METHODS

This study included 108 patients who underwent ¹⁸F-FDG-PET/CT scans for the purpose of cancer screening. We examined four different ROIs and VOIs; a 3-cm-diameter and a 4-cm-diameter circular ROI and a 3-cm-diameter and a 4-cm-diameter spherical VOI on the right lobe of the patients' livers. The average of SUV (SUV_mean), standard deviation (SD) of SUV (SUV_SD), SNR_liver and SD of the SNR_liver obtained using ROIs and VOIs were then compared.

RESULTS

Although the SUV_mean was not different among the ROIs and VOIs, the SUV_SD was small with a 3-cm-diameter ROI. The largest SUV_SD was obtained with a 4-cm-diameter spherical VOI. The SNR_liver and the SD of the SNR_liver with a 4-cm-diameter spherical VOI were the smallest, while those with a 3-cm-diameter circular ROI were the largest. These results suggest that a small ROI may be placed on a relatively homogeneous region not representing whole liver unintentionally.

CONCLUSION

The SNR_liver varied according to the shape and size of ROIs or VOIs. A 4-cm-diameter spherical VOI is recommended to obtain stable and reproducible SNR_liver.

Fluorodeoxyglucose-positron emission tomography/computed tomography performs better than contrast-enhanced computed tomography for metastasis evaluation in the initial staging of pancreatic adenocarcinoma

OBJECTIVE

To evaluate the additional role of FDG-PET/CT to the conventional multiphasic CECT in the initial staging of pancreatic adenocarcinoma.

METHODS

54 patients diagnosed with pathologically proven pancreatic malignancy underwent FDG-PET/CECT. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT for nodal and metastatic staging were calculated. The statistical difference was calculated by McNemar's test.

RESULTS

Of 54 patients, 15 had distal metastasis. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT for nodal staging were 33 vs 89%, 84 vs 100%, 67 vs 100%, 60 vs 90%, and 59 vs 95%, respectively, p < 0.001. The sensitivity, specificity, PPV, NPV, and accuracy of CECT for metastatic staging were 73, 87, 69, 89, and 83%, whereas the accuracy of PET/CT was 100%, p = 0.01. By correctly characterizing unsuspected distant lesions, PET/CT could change management in 19% of patients.

CONCLUSION

FDG-PET/CT can contribute to change in the management in almost one of every five patients of PA evaluated with the standard investigations during the initial staging.

LSL-KrasG12D; LSL-Trp53R172H/+; Ink4flox/+; Ptf1/p48-Cre mice are an applicable model for locally invasive and metastatic pancreatic cancer

Pancreatic cancer (PC) accumulates multiple genetic mutations, including activating KRAS mutations and inactivating TP53, SMAD4 and CDKN2A mutations, during progression. The combination of mutant KRAS with a single inactivating TP53, SMAD4 or CDKN2A mutation in genetically engineered mouse models (GEMMs) showed that these mutations exert different synergistic effects in PC. However, the effect of the combination of TP53, CDKN2A and KRAS mutations on the trajectory of PC progression is unknown. Here, we report a GEMM that harbors KRAS (Kras^G12D), TP53 (Trp53^R172H/+), CDKN2A (Ink4^flox/+) and Ptf1/p48-Cre (KPIC) mutations. Histopathology showed that KPIC mice developed adenocarcinoma that strongly resembled the pathology of human PC, characterized by rich desmoplastic stroma and low microvascularity. The median survival of KPIC mice was longer than that of LSL-Kras^G12D; Ink4^flox/flox; Ptf1/p48-Cre mice (KIC) (89 vs 62 days) and shorter than that of KRAS (Kras^G12D), TP53 (Trp53^R172H/+) and Ptf1/p48-Cre (KPC) mice. Moreover, the neoplastic cells of KPIC mice were epithelial, highly proliferative tumor cells that exhibited ERK and MAPK pathway activation and high glucose uptake. Isolated neoplastic cells from spontaneous KPIC tumors showed all molecular profiles and cellular behaviors of spontaneous KPIC tumors, including epithelial-mesenchymal transition (EMT) under drug stress as well as tumorigenic, metastatic and invasive abilities in immunocompetent mice. Furthermore, orthotopic and metastatic tumors of KPIC cells almost recapitulated the pathology of spontaneous KPIC tumors. These data show that in addition to spontaneous KPIC tumors, KPIC cells are a valuable tool for preclinical studies of locally invasive and metastatic PC.

Phase II study of induction chemotherapy followed by chemoradiotherapy in patients with borderline resectable and unresectable locally advanced pancreatic cancer

There is not a clear consensus regarding the optimal treatment of locally advanced pancreatic disease. There is a potential role for neoadjuvant therapy to treat micrometastatic disease with chemotherapy, as well as for the treatment of local disease with radiotherapy. We evaluated the safety and efficacy of induction chemotherapy with oxaliplatin and gemcitabine followed by a high weekly dose of gemcitabine concurrent to radiation therapy in patients with borderline resectable and unresectable locally advanced pancreatic cancer. In our study, 41 patients with pancreatic cancer were evaluated. In all cases an accurate pre-treatment staging was performed. Patients with evidence of metastatic disease were excluded, and thus a total of 34 patients were consequently enrolled. Of these, twenty-seven patients (80%) had locally advanced unresectable tumours, seven patients (20%) had borderline resectable disease. This protocol treatment represents a well-tolerated promising approach. Fifteen patients (55.5%) underwent surgical radical resection. With a median follow-up of 20 months, the median PFS and OS were 20 months and 19.2 months, respectively. The median OS for borderline resectable patients was 21.5 months compared with 14 months for unresectable patients (p = 0.3). Continued optimization in multimodality therapy and an accurate patient selection remain crucial points for the appropriate treatment of these patients.

Novel Diagnostic and Predictive Biomarkers in Pancreatic Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease for a multitude of reasons including very late diagnosis. This in part is due to the lack of understanding of the biological behavior of PDAC and the ineffective screening for this disease. Significant efforts have been dedicated to finding the appropriate serum and imaging biomarkers to help early detection and predict response to treatment of PDAC. Carbohydrate antigen 19-9 (CA 19-9) has been the most validated serum marker and has the highest positive predictive value as a stand-alone marker. When combined with carcinoembryonic antigen (CEA) and carbohydrate antigen 125 (CA 125), CA 19-9 can help predict the outcome of patients to surgery and chemotherapy. A slew of novel serum markers including multimarker panels as well as genetic and epigenetic materials have potential for early detection of pancreatic cancer, although these remain to be validated in larger trials. Imaging studies may not correlate with elevated serum markers. Critical features for determining PDAC include the presence of a mass, dilated pancreatic duct, and a duct cut-off sign. Features that are indicative of early metastasis includes neurovascular bundle involvement, duodenal invasion, and greater post contrast enhancement. 18-F-fluorodeoxyglucose (18-FDG) radiotracer uptake and changes following treatment may predict patient overall survival following treatment. Similarly, pretreatment apparent diffusion coefficient (ADC) values may predict prognosis with lower ADC lesions having worse outcome. Although these markers have provided significant improvement in the care of pancreatic cancer patients, further advancements can be made with perhaps better combination of markers or discovery of unique marker(s) to pancreatic cancer.

Clinically determined type of 18F-fluoro-2-deoxyglucose uptake as an alternative prognostic marker in resectable pancreatic cancer

PURPOSE

To investigate the association between clinical PET (positron emission tomography) type and oncologic outcome in resectable pancreatic cancer.

METHODS

Between January 2008 and October 2012, patients who underwent potentially curative resection for resectable pancreatic ductal adenocarcinoma without neoadjuvant treatment were retrospectively investigated. Clinical PET type was defined as follows: pancreatic cancer with similar 18FDG uptake to renal calyx was determined as kidney-type (K-type), and relatively lower 18FDG uptake than that of renal calyx was regarded as Non-K type.

RESULTS

A total of 53 patients were enrolled. After agreement-based reclassification, agreement based K-type (aK-type) was noted in 34 patients (64.2%), and agreement based Non-K type (aNon K-type) was found in 19 patients (35.8%). There was a significant difference between aK-type and aNon K-type pancreatic cancer (tumor size (P = 0.030), adjusted CA 19-9 (P = 0.007), maximum standard uptake value (SUVmax,P<0.001), metabolic tumor volume (MTV2.5, P<0.001), total lesion glycolysis (TLG, P<0.001)). K-type pancreatic cancer (n = 31) showed a significantly shorter disease-free time compared with Non-K type (n = 16) (10.8 vs. 24.1 months, P = 0.013). It was also noted that aK-type showed inferior disease-free survival to that of aNon-K type pancreatic cancer (11.9 vs. 28.6 months, P = 0.012).

CONCLUSIONS

Clinical PET type is a reliable clinical marker to estimate aggressive tumor biology and can be utilized in predicting tumor recurrence and necessity for postoperative chemotherapy.

Identifying prognostic intratumor heterogeneity using pre- and post-radiotherapy 18F-FDG PET images for pancreatic cancer patients

BACKGROUND

To stratify risks of pancreatic adenocarcinoma (PA) patients using pre- and post-radiotherapy (RT) PET/CT images, and to assess the prognostic value of texture variations in predicting therapy response of patients.

METHODS

Twenty-six PA patients treated with RT from 2011-2013 with pre- and post-treatment 18F-FDG-PET/CT scans were identified. Tumor locoregional texture was calculated using 3D kernel-based approach, and texture variations were identified by fitting discrepancies of texture maps of pre- and post-treatment images. A total of 48 texture and clinical variables were identified and evaluated for association with overall survival (OS). The prognostic heterogeneity features were selected using lasso/elastic net regression, and further were evaluated by multivariate Cox analysis.

RESULTS

Median age was 69 y (range, 46-86 y). The texture map and temporal variations between pre- and post-treatment were well characterized by histograms and statistical fitting. The lasso analysis identified seven predictors (age, node stage, post-RT SUVmax, variations of homogeneity, variance, sum mean, and cluster tendency). The multivariate Cox analysis identified five significant variables: age, node stage, variations of homogeneity, variance, and cluster tendency (with P=0.020, 0.040, 0.065, 0.078, and 0.081, respectively). The patients were stratified into two groups based on the risk score of multivariate analysis with log-rank P=0.001: a low risk group (n=11) with a longer mean OS (29.3 months) and higher texture variation (>30%), and a high risk group (n=15) with a shorter mean OS (17.7 months) and lower texture variation (<15%).

CONCLUSIONS

Locoregional metabolic texture response provides a feasible approach for evaluating and predicting clinical outcomes following treatment of PA with RT. The proposed method can be used to stratify patient risk and help select appropriate treatment strategies for individual patients toward implementing response-driven adaptive RT.

Five-Year Actual Overall Survival in Resected Pancreatic Cancer: A Contemporary Single-Institution Experience from a Multidisciplinary Perspective

BACKGROUND

Successful surgical resection combined with effective perioperative therapy is essential for maximizing long-term survival for pancreatic adenocarcinoma.

PATIENTS AND METHODS

All patients with pancreatic adenocarcinoma who underwent curative resection at our institution from January 2003 to May 2010 were reviewed. Demographic and clinical details were retrospectively collected from medical records and cancer registry data.

RESULTS

Overall, 176 patients were included in the analysis (148 with de novo resectable disease and 28 with borderline resectable disease at presentation). Among 106 patients who received all perioperative therapy at our institution, 94% received neoadjuvant and/or adjuvant treatment in addition to resection. Actual all-cause 5-year overall survival (OS) for all 176 patients was 30.7%, with a median OS of 33.9 months [95% confidence interval (CI) 28.1-39.6 months]. For patients who received all perioperative therapy at our institution, actual all-cause 5-year disease-free survival (DFS) was 32.1%, with a median DFS of 28.8 months (95% CI 20.1-43.6 months). Of these patients, 67/106 (63%) recurred: 8 (8%) locoregional only; 52 (49%) systemic only; and 7 (7%) combined recurrence. No difference in survival rates or recurrence patterns was seen between resectable and borderline resectable patients. In multivariate analysis, tumor differentiation (poor vs. non-poor) and lymph node ratio >20% produced a useful clinical model.

CONCLUSION

The actual OS rates for resected pancreatic cancer shown in this study are reflective of those currently achievable at a tertiary medical center dedicated to this patient population. In considering these results, both frequency and type of adjuvant/neoadjuvant therapy administered in the context of the clinical experience/management techniques of providers administering these treatments will be discussed.

Significance of pathological positive superior mesenteric/portal venous invasion in pancreatic cancer

BACKGROUND

Pancreaticoduodenectomy with superior mesenteric/portal venous resection for pancreatic ductal adenocarcinoma (PDAC) is frequently performed with no added morbidity or mortality in case of tumor abutment to the superior mesenteric or portal vein so as to obtain a margin negative resection. True histopathological portal vein invasion is found only in a small subset of such patients. The aim of this review aimed to discuss the significance of histopathological venous invasion in PDAC.

DATA SOURCES

For this review available data was searched from PubMed and analyzed. No randomized trials have been published on this topic.

RESULTS

Existing data on prognostic factors in histopathological venous invasion by PDAC are limited and recent studies indicate worse survival in this subgroup of patients. In addition, venous invasion in PDAC has been associated with large tumors, involved lymph nodes, perineural invasion and R1 resection. The survival of patients with portal venous resection but without histologic venous invasion is reportedly better than those with histopathological venous invasion; though conflicting studies do exist on the subject. Some studies also relate the depth of venous invasion to prognosis after surgical resection of PDAC.

CONCLUSIONS

Frank/'histopathological' invasion of superior mesenteric/portal venous and R1 resection indicate a very poor survival. Such patients may be given the opportunity of benefit of neoadjuvant treatment.

Personalized Clinical Decision Making in Gastrointestinal Malignancies: The Role of PET

Gastrointestinal malignancies comprise a heterogeneous group of diseases that include both common and rare diseases with very different presentations and prognoses. The mainstay of treatment is surgery in combination with preoperative and adjuvant chemotherapy depending on clinical presentation and initial stages. This article outlines the potential use of fluorodeoxyglucose-PET/CT in clinical decision making with special regard to preoperative evaluation and response assessment in gastric cancer (including the gastroesophageal junction), pancreatic cancer (excluding neuroendocrine tumors), colorectal cancer, and gastrointestinal stromal tumors.

Combining in Vitro Diagnostics with in Vivo Imaging for Earlier Detection of Pancreatic Ductal Adenocarcinoma: Challenges and Solutions

Pancreatic ductal adenocarcinoma (PDAC) is the fourth-leading cause of cancer-related death in the United States and is associated with a dismal prognosis, particularly when diagnosed at an advanced stage. Overall survival is significantly improved if PDAC is detected at an early stage prior to the onset of symptoms. At present, there is no suitable screening strategy for the general population. Available diagnostic serum markers are not sensitive or specific enough, and clinically available imaging modalities are inadequate for visualizing early-stage lesions. In this article, the role of currently available blood biomarkers and imaging tests for the early detection of PDAC will be reviewed. Also, the emerging biomarkers and molecularly targeted imaging agents being developed to improve the specificity of current imaging modalities for PDAC will be discussed. A strategy incorporating blood biomarkers and molecularly targeted imaging agents could lead to improved screening and earlier detection of PDAC in the future. (©) RSNA, 2015.

Preoperative Volume-Based PET Parameter, MTV2.5, as a Potential Surrogate Marker for Tumor Biology and Recurrence in Resected Pancreatic Cancer

This study aims to evaluate the role of volume-based positron emission tomography parameters as potential surrogate markers for tumor recurrence in resected pancreatic cancer. Between January 2008 and October 2012, medical records of patients who underwent surgical resection for pancreatic ductal adenocarcinoma and completed ¹⁸F-fluorodeoxyglucose positron emission tomography/CT as a part of preoperative staging work-up were retrospectively reviewed. Not only clinicopathologic variables but also positron emission tomography parameters such as SUVmax, MTV2.5 (metabolic tumor volume), and TLG (total lesion glycolysis) were obtained. Twenty-six patients were women and 31 were men with a mean age of 62.9 ± 9.1 years. All patients were preoperatively determined to resectable pancreatic cancer except 1 case with borderline resectability. R0 resection was achieved in all patients and 45 patients (78.9%) received postoperative adjuvant chemotherapy with or without radiation therapy. Median overall disease-free survival was 12.8 months with a median overall disease-specific survival of 25.1 months. SUVmax did not correlate with radiologic tumor size (P = 0.501); however, MTV2.5 (P = 0.001) and TLG (P = 0.009) were significantly associated with radiologic tumor size. In addition, MTV2.5 (P < 0.001) and TLG (P < 0.001) were significantly correlated with a tumor differentiation. There were no significant differences in TLG and SUVmax according to lymph node ratio; only MTV2.5 was related to lymph node ratio with marginal significance (P = 0.055). In multivariate analysis, lymph node ratio (Exp [β] = 2.425, P = 0.025) and MTV2.5 (Exp[β] = 2.273, P = 0.034) were identified as independent predictors of tumor recurrence following margin-negative resection. Even after tumor size-matched analysis, MTV2.5 was still identified as significant prognostic factor in resected pancreatic cancer (P < 0.05). However, preoperative neoadjuvant treatment attenuated adverse oncologic impact of high preoperative MTV2.5 (P = 0.210). Preoperatively determined volume-based PET parameter, MTV2.5, can potentially be used as a surrogate marker to estimate tumor biology and tumor recurrence. Individual treatment strategies for pancreatic cancer can be suggested based on patients' preoperative MTV2.5.

Value of 18F-fluorodeoxyglucose positron emission tomography and 18F-fluorodeoxyglucose positron emission tomography/computed tomography in diagnosis of pancreatic cancer: A systemic review and meta-analysis

AIM: To evaluate the value of ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) and ¹⁸F-FDG PET/computed tomography (CT) in the diagnosis of pancreatic cancer.

METHODS: Medline, EMBASE, Science Direct, Springer link, CBM, Cnki, Wan fang and VIP databases were searched by computer before April 1, 2015 to retrieve articles on the study of ¹⁸F-FDG PET and ¹⁸F-FDG PET/CT in diagnosing pancreatic cancer. Studies were selected according to the inclusion and exclusion criteria, and quality assessment was made using the QUADAS scale. Meta-Disc 1.4 software was used to analyze the heterogeneity of the included articles, and the SROC curve was plotted to calculate the pooled sensitivity and specificity. The publication bias was assessed with Stata 12.0 software.

RESULTS: A total of 51 English-language articles were included. The summary sensitivity and specificity of ¹⁸F-FDG PET in diagnosing pancreatic cancer were 87% (95%CI: 85%-89%) and 78% (95%CI: 74%-81%), respectively. The positive and negative likelihood ratios were 3.38 (95%CI: 2.64-4.33) and 0.18 (95%CI: 0.14-0.23), respectively. The diagnostic odds ratio (DOR) was 21.91 (95%CI: 14.15-33.93), and the area under the SROC curve was 0.8930. The summary sensitivity and specificity of ¹⁸F-FDG PET/CT in diagnosing pancreatic cancer were 91% (95%CI: 88%-93%) and 77% (95%CI: 72%-82%), respectively. The positive and negative likelihood ratios were 3.57 (95%CI: 2.96-4.31) and 0.14 (95%CI: 0.11-0.18), respectively. The DOR was 28.52 (95%CI: 19.63-41.42), and the area under the SROC curve was 0.9315.

CONCLUSION: ¹⁸F-FDG PET/CT and ¹⁸F-FDG PET have higher diagnostic value than CT in diagnosing pancreatic cancer. ¹⁸F-FDG PET/CT is superior to ¹⁸F-FDG PET in terms of sensitivity and both of them can be used as diagnostic tools for pancreatic cancer with negative traditional examinations.

HIFU for Palliative Treatment of Pancreatic Cancer

Pancreatic cancer is one of the deadliest malignancies, with only a 6 % 5-year survival rate and over 50 % of patients being diagnosed at the advanced stage. Current therapies are ineffective, and the treatment of patients with advanced disease is palliative. In the past decade, HIFU ablation has emerged as a modality for palliative treatment of pancreatic tumors. Multiple preclinical and non-randomized clinical trials have been performed to evaluate the safety and efficacy of this procedure. Substantial tumor-related pain reduction was achieved in most cases after HIFU treatment and few significant side effects were observed. In addition, some studies indicate that combination of HIFU ablation with chemotherapy may provide a survival benefit. This chapter summarizes the pre-clinical and clinical experience obtained to date in HIFU treatment of pancreatic tumors and discusses the challenges, limitations and new approaches in this modality.

Current State of Vascular Resections in Pancreatic Cancer Surgery

Pancreatic cancer (PDAC) is the fourth leading cause of cancer-related mortality in the Western world and, even in 2014, a therapeutic challenge. The only chance for long-term survival is radical surgical resection followed by adjuvant chemotherapy which can be performed in about 20% of all PDAC patients by the time of diagnosis. As pancreatic surgery has significantly changed during the past years, extended operations, including vascular resections, have become more frequently performed in specialized centres and the border of resectability has been pushed forward to achieve a potentially curative approach in the respective patients in combination with neoadjuvant and adjuvant treatment strategies. In contrast to adjuvant treatment which has to be regarded as a cornerstone to achieve long-term survival after resection, neoadjuvant treatment strategies for locally advanced findings are currently under debate. This overview summarizes the possibilities and evidence of vascular, namely, venous and arterial, resections in PDAC surgery.