Metabolic activity by FDG-PET/CT after neoadjuvant chemotherapy in borderline resectable and locally advanced pancreatic cancer and association with survival

Value of [18F]AlF-NOTA-FAPI-04 PET/CT for predicting pathological response and survival in patients with locally advanced pancreatic ductal adenocarcinoma receiving neoadjuvant chemotherapy

OBJECTIVES

This study aimed to evaluate the predictive value of [18F]AlF-NOTA-FAPI-04 PET/CT for pathological response to neoadjuvant chemotherapy (NCT) and prognosis in patients with locally advanced pancreatic ductal adenocarcinoma (LAPDAC).

METHODS

This study included 34 patients with histopathologically and radiologically confirmed LAPDAC who received [18F]AlF-NOTA-FAPI-04 PET/CT scans before NCT. After 4-6 cycles of NCT, these patients underwent radical resection. Pathological response to NCT was assessed by pathological tumor regression grades (TRG) based on the Evans system. PET/CT parameters were evaluated for their association with TRG, recurrence-free survival (RFS) and overall survival (OS) after NCT, including the maximum standardized uptake value (SUVmax), FAPI-avid tumor volume (FTV), total lesion FAP expression (TLF) of primary tumor, total FAPI-avid pancreatic volume (FPV) and total pancreatic FAP expression (TPF) of total pancreas.

RESULTS

Of 34 patients with LAPDAC, 14 patients had a pathologic good response (PGR, Evans III-IV), and 20 patients had a pathologic poor response (PPR, Evans I-II). Both the primary tumor SUVmax, FTV and TLF, and total pancreas FPV and TPF in the PGR groups were significantly lower than those in the PPR groups. Furthermore, SUVmax and TLF were higher in poorly differentiated LAPDAC than in well-moderately differentiated neoplasms. The FTV, TLF, FPV and TPF were closely associated with RFS and OS. On multivariate analysis, patients with FTV > 54.21 and TLF > 290.21 had a worse RFS and OS, respectively (HR = 3.24, P = 0.014 and HR = 3.35, P = 0.019) and OS (HR = 7.35, P = 0.002 and HR = 7.09, P = 0.004) in LAPDAC after NCT.

CONCLUSIONS

The parameters of [18F]AlF-NOTA-FAPI-04 PET/CT had the excellent performance for predicting pathologic TRG after NCT in LAPDAC. FTV and TLF were independent postoperative prognostic factors for RFS and OS for LAPDAC.

Prospective Comparison of [18F]FDG and [18F]AIF-FAPI-74 PET/CT in the Evaluation of Potentially Resectable Pancreatic Ductal Adenocarcinoma

PURPOSE

Accurate clinical staging of potentially resectable pancreatic ductal adenocarcinoma (PDAC) is critical for establishing optimal treatment strategies. While the efficacy of fluorine-18-fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) in clinical staging is unclear, PET/CT detecting fibroblast-activation protein (FAP) expression has recently received considerable attention for detecting various tumors, including PDAC, with high sensitivity. We explored the efficacy of [18F]FDG and [18F]AIF-FAPI-74 PET/CT in the initial evaluation of potentially resectable PDAC.

PROCEDURES

Between 2021 and 2022, twenty participants with newly diagnosed potentially resectable PDAC were enrolled. After the initial evaluation with pancreatic CT, [18F]FDG PET/CT, and [18F]AIF-FAPI-74 PET/CT, treatment strategies were determined considering the participant's general status, clinical staging, and resectability. Pathological information from the surgical specimens was only available in 17 participants who underwent curative-intent surgery. Head-to-head comparisons of quantitative radiotracer uptake and diagnostic performance were performed among imaging modalities.

RESULTS

[18F]AIF-FAPI-74 PET/CT showed a significantly higher maximum standardized uptake value than [18F]FDG PET/CT did in evaluating primary pancreatic lesions (median [interquartile range]; 12.6 [10.7-13.7] vs. 6.3 [4.8-9.2]; P < 0.001). In contrast, [18F]AIF-FAPI-74 PET/CT showed a significantly lower mean standardized uptake value than [18F]FDG PET/CT did in evaluating background organ (median [interquartile range]) 0.8 [0.7-0.9] vs. 2.6 [2.3-2.7]; P < 0.001). In addition, the sensitivity of [18F]AIF-FAPI-74 PET/CT in detecting metastatic lymph nodes was higher than that of [18F]FDG PET/CT (50.0% vs. 0.0%; P = 0.026).

CONCLUSION

This study demonstrated that [18F]AIF-FAPI-74 PET/CT could improve the clinical staging of potentially resectable PDAC.

Computed tomography-based vascular burden index as a predictor of vascular resection and pathological vascular invasion in pancreatic cancer with neo-adjuvant chemotherapy

BACKGROUND

Determination of vessel resection in patients with pancreatectomy after neo-adjuvant chemotherapy remains controversial. The recently introduced computed tomography-based vascular burden index presents a potential solution to this challenge. This study aimed to evaluate the model performance for the prediction of vascular resection and pathological invasion.

METHODS

Patients who underwent surgery after neo-adjuvant chemotherapy were included. Two independent reviewers measured the vascular tumour burden index around the adjacent artery (AVBI), and vein (VVBI). The area under the curve was compared to assess the predictive capacity of vascular burden index values and their changes for vascular resection and pathological vascular invasion.

RESULTS

Among 252 patients, 179 and 73 had borderline resectable and locally advanced pancreatic cancer, respectively. Concurrent vessel resection and pathological vascular invasion were observed in 121 (48.0 %) and 42 (16.6 %) patients, respectively. In all patients, the VVBI (area under the curve: 0.872) and AVBI (0.911) after neo-adjuvant therapy significantly predicted vessel resection. In patients with vascular resection, the VVBI after neo-adjuvant chemotherapy (0.752) and delta value of the AVBI (0.706) demonstrated better performance for predicting pathological invasion of the resected vein. The regression of the AVBI and VVBI was an independent prognostic factor for survival (hazard ratio: 0.54, 95 % confidence interval: 0.34-0.85; P = 0.009) CONCLUSIONS: Regressed VVBI on serial computed tomography scans is useful for predicting vein resection and pathological venous invasion before surgery. The delta value of the AVBI may therefore be helpful for predicting pathological arterial invasion after neo-adjuvant chemotherapy.

Integrated 68 Ga-FAPI-04 PET/MR in Pancreatic Cancer : Prediction of Tumor Response and Tumor Resectability After Neoadjuvant Therapy

PURPOSE

This study aimed to investigate the value of 68 Ga-fibroblast activation protein inhibitor (FAPI) PET/MR semiquantitative parameters in the prediction of tumor response and resectability after neoadjuvant therapy in patients with pancreatic cancer.

PATIENTS AND METHODS

This study was performed retrospectively in patients with borderline resectable or locally advanced pancreatic cancer who underwent 68 Ga-FAPI PET/MRI from June 2020 to June 2022. The SUV max , SUV mean , SUV peak , uptake tumor volume (UTV), and total lesion FAP expression (TLF) of the primary tumor were recorded. The target-to-background ratios (TBRs) of the primary tumor to normal tissue muscle (TBR muscle ) and blood (TBR blood ) were also calculated. In addition, the minimum apparent diffusion coefficient value of the tumor was measured. After 3-4 cycles of gemcitabine + nab-paclitaxel chemotherapy, patients were divided into responders and nonresponders groups according to RECIST criteria (v.1.1). They were also divided into resectable and unresectable groups according to the surgical outcome. The variables were compared separately between groups.

RESULTS

A total of 18 patients who met the criteria were included in this study. The UTV and TLF were significantly higher in nonresponders than in responders ( P < 0.05). The SUV max , SUV mean , and TBR muscle were significantly higher in unresectable patients than in resectable ones ( P < 0.05). Receiver operating characteristic curve analysis identified UTV (area under the curve [AUC] = 0.840, P = 0.015) and TLF (AUC = 0.877, P = 0.007) as significant predictors for the response to gemcitabine + nab-paclitaxel chemotherapy, with cutoff values of 25.05 and 167.38, respectively. In addition, SUV max (AUC = 0.838, P = 0.016), SUV mean (AUC = 0.812, P = 0.026), and TBR muscle (AUC = 0.787, P = 0.041) were significant predictors of the resectability post-NCT, with cutoff values of 14.0, 6.0, and 13.9, respectively. According to logistic regression analysis, TLF was found to be significantly associated with tumor response ( P = 0.032) and was an independent predictor of tumor response ( P = 0.032). In addition, apparent diffusion coefficient value was an independent predictor of tumor resectability ( P = 0.043).

CONCLUSIONS

This pilot study demonstrates the value of 68 Ga-FAPI PET/MR for the prediction of tumor response and resectability after neoadjuvant therapy. It may aid in individualized patient management by guiding the treatment regimens.

Stereotactic Body Radiation Therapy for Locally Advanced Pancreatic Cancer

Introduction

For patients with locally advanced pancreatic cancer (LAPC), who are candidates for radiation therapy, dose-escalated radiation therapy (RT) offers unique benefits over traditional radiation techniques. In this review, we present a historical perspective of dose-escalated RT for LAPC. We also outline advances in SBRT delivery, one form of dose escalation and a framework for selecting patients for treatment with SBRT.

Results

Techniques for delivering SBRT to patients with LAPC have evolved considerably, now allowing for dose-escalation and superior respiratory motion management. At the same time, advancements in systemic therapy, particularly the use of induction multiagent chemotherapy, have called into question which patients would benefit most from radiation therapy. Multidisciplinary assessment of patients with LAPC is critical to guide management and select patients for local therapy. Results from ongoing trials will establish if there is a role of dose-escalated SBRT after induction chemotherapy for carefully selected patients.

Conclusion

Patients with LAPC have more therapeutic options than ever before. Careful selection for SBRT may enhance patient outcomes, pending the maturation of pivotal clinical trials.

Predicting Recurrence-Free Survival After Upfront Surgery in Resectable Pancreatic Ductal Adenocarcinoma: A Preoperative Risk Score Based on CA 19-9, CT, and 18F-FDG PET/CT

OBJECTIVE

To develop and validate a preoperative risk score incorporating carbohydrate antigen (CA) 19-9, CT, and fluorine-18-fluorodeoxyglucose (18F-FDG) PET/CT variables to predict recurrence-free survival (RFS) after upfront surgery in patients with resectable pancreatic ductal adenocarcinoma (PDAC).

MATERIALS AND METHODS

Patients with resectable PDAC who underwent upfront surgery between 2014 and 2017 (development set) or between 2018 and 2019 (test set) were retrospectively evaluated. In the development set, a risk-scoring system was developed using the multivariable Cox proportional hazards model, including variables associated with RFS. In the test set, the performance of the risk score was evaluated using the Harrell C-index and compared with that of the postoperative pathological tumor stage.

RESULTS

A total of 529 patients, including 335 (198 male; mean age ± standard deviation, 64 ± 9 years) and 194 (103 male; mean age, 66 ± 9 years) patients in the development and test sets, respectively, were evaluated. The risk score included five variables predicting RFS: tumor size (hazard ratio [HR], 1.29 per 1 cm increment; P < 0.001), maximal standardized uptake values of tumor ≥ 5.2 (HR, 1.29; P = 0.06), suspicious regional lymph nodes (HR, 1.43; P = 0.02), possible distant metastasis on 18F-FDG PET/CT (HR, 2.32; P = 0.03), and CA 19-9 (HR, 1.02 per 100 U/mL increment; P = 0.002). In the test set, the risk score showed good performance in predicting RFS (C-index, 0.61), similar to that of the pathologic tumor stage (C-index, 0.64; P = 0.17).

CONCLUSION

The proposed risk score based on preoperative CA 19-9, CT, and 18F-FDG PET/CT variables may have clinical utility in selecting high-risk patients with resectable PDAC.

Metabolic tumor burden as a prognostic indicator after neoadjuvant chemotherapy in pancreatic cancer

BACKGROUND

There is no standardized assessment for evaluating response although neoadjuvant chemotherapy (NAT) is widely accepted for borderline resectable or locally advanced pancreatic cancer (BRPC or LAPC). This study was aimed to evaluate NAT response using positron emission tomography (PET) with 2-deoxy-2-[fluorine-18]fluoro-D-glucose ( 18 F-FDG-PET/CT) parameters alongside carbohydrate antigen (CA) 19-9 levels.

METHODS

Patients who underwent surgery after NAT for BRPC and LAPC between 2017 and 2021 were identified. The study assessed the prognostic value of PET-derived parameters after NAT, determining cutoff values using the K-adaptive partitioning method. It created four groups based on the elevation or normalization of PET parameters and CA19-9 levels, comparing survival between these groups.

RESULTS

Of 200 eligible patients, FOLFIRINOX and gemcitabine-based NAT was administered in 166 and 34 patients, respectively (mean NAT cycles, 8.3). In a multivariate analysis, metabolic tumor volume (MTV) demonstrated the most robust performance in assessing response [hazard ratio (HR) 3.11, 95% confidence interval (CI) 1.73-5.58, P <0.001] based on cutoff value of 2.4. Patients with decreased MTV had significantly better survival than those with elevated MTV among individuals with CA19-9 levels less than 37 IU/l (median survival; 35.5 vs. 20.9 months, P <0.001) and CA19-9 levels at least 37 IU/l (median survival; 34.3 vs. 17.8 months, P =0.03). In patients suspected to be Lewis antigen negative, the predictive performance of MTV was found to be limited ( P =0.84).

CONCLUSION

Elevated MTV is an influential prognostic factor for worse survival, regardless of post-NAT CA19-9 levels. These results could be helpful in identifying patients with a poor prognosis despite normalization of CA19-9 levels after NAT.

Total Neoadjuvant Therapy in Localized Pancreatic Cancer: Is More Better?

Pancreatic ductal adenocarcinoma (PDAC) poses a significant challenge in oncology due to its advanced stage upon diagnosis and limited treatment options. Surgical resection, the primary curative approach, often results in poor long-term survival rates, leading to the exploration of alternative strategies like neoadjuvant therapy (NAT) and total neoadjuvant therapy (TNT). While NAT aims to enhance resectability and overall survival, there appears to be potential for improvement, prompting consideration of alternative neoadjuvant strategies integrating full-dose chemotherapy (CT) and radiotherapy (RT) in TNT approaches. TNT integrates chemotherapy and radiotherapy prior to surgery, potentially improving margin-negative resection rates and enabling curative resection for locally advanced cases. The lingering question: is more always better? This article categorizes TNT strategies into six main groups based on radiotherapy (RT) techniques: (1) conventional chemoradiotherapy (CRT), (2) the Dutch PREOPANC approach, (3) hypofractionated ablative intensity-modulated radiotherapy (HFA-IMRT), and stereotactic body radiotherapy (SBRT) techniques, which further divide into (4) non-ablative SBRT, (5) nearly ablative SBRT, and (6) adaptive ablative SBRT. A comprehensive analysis of the literature on TNT is provided for both borderline resectable pancreatic cancer (BRPC) and locally advanced pancreatic cancer (LAPC), with detailed sections for each.

Neoadjuvant treatment of pancreatic ductal adenocarcinoma: Whom, when and how

Pancreatic ductal adenocarcinoma (PDAC), which is notorious for its aggressiveness and poor prognosis, remains an area of great unmet medical need, with a 5-year survival rate of 10% - the lowest of all solid tumours. At diagnosis, only 20% of patients have resectable pancreatic cancer (RPC) or borderline RPC (BRPC) disease, while 80% of patients have unresectable tumours that are locally advanced pancreatic cancer (LAPC) or have distant metastases. Nearly 60% of patients who undergo upfront surgery for RPC are unable to receive adequate adjuvant chemotherapy (CHT) because of postoperative complications and early cancer recurrence. An important paradigm shift to achieve better outcomes has been the sequence of therapy, with neoadjuvant CHT preceding surgery. Three surgical stages have emerged for the preoperative assessment of nonmetastatic pancreatic cancers: RPC, BRPC, and LAPC. The main goal of neoadjuvant treatment (NAT) is to improve postoperative outcomes through enhanced selection of candidates for curative-intent surgery by identifying patients with aggressive or metastatic disease during initial CHT, reducing tumour volume before surgery to improve the rate of margin-negative resection (R0 resection, a microscopic margin-negative resection), reducing the rate of positive lymph node occurrence at surgery, providing early treatment of occult micrometastatic disease, and assessing tumour chemosensitivity and tolerance to treatment as potential surgical criteria. In this editorial, we summarize evidence concerning NAT of PDAC, providing insights into future practice and study design. Future research is needed to establish predictive biomarkers, measures of therapeutic response, and multidisciplinary strategies to improve patient-centered outcomes.

Preoperative chemotherapy, radiotherapy and surgical decision-making in patients with borderline resectable and locally advanced pancreatic cancer

Surgical resection combined with systemic chemotherapy is the cornerstone of treatment for patients with localized pancreatic cancer. Upfront surgery is considered suboptimal in cases with extensive vascular involvement, which can be classified as either borderline resectable pancreatic cancer or locally advanced pancreatic cancer. In these patients, FOLFIRINOX or gemcitabine plus nab-paclitaxel chemotherapy is currently used as preoperative chemotherapy and is eventually combined with radiotherapy. Thus, more patients might reach 5-year overall survival. Patient selection for chemotherapy, radiotherapy and subsequent surgery is based on anatomical, biological and conditional parameters. Current guidelines and clinical practices vary considerably regarding preoperative chemotherapy and radiotherapy, response evaluation, and indications for surgery. In this Review, we provide an overview of the clinical evidence regarding disease staging, preoperative therapy, response evaluation and surgery in patients with borderline resectable pancreatic cancer or locally advanced pancreatic cancer. In addition, a clinical work-up is proposed based on the available evidence and guidelines. We identify knowledge gaps and outline a proposed research agenda.

In Neoadjuvant FOLFIRINOX Chemotherapy for Pancreatic Ductal Adenocarcinoma, Which Response is the More Reliable Indicator for Prognosis, Radiologic or Biochemical?

BACKGROUND

In this era of increasing neoadjuvant chemotherapy, methods for evaluating responses to neoadjuvant chemotherapy are still diverse among institutions. Additionally, the efficacy of adjuvant chemotherapy for patients undergoing neoadjuvant chemotherapy remains unclear. Therefore, this retrospective study was performed to evaluate the effectiveness of methods for assessing response to neoadjuvant chemotherapy and the need for adjuvant chemotherapy in treating patients with non-metastatic pancreatic ductal adenocarcinoma.

METHODS

The study identified 150 patients who underwent neoadjuvant FOLFIRINOX chemotherapy followed by curative-intent pancreatectomy. The patients were stratified by biochemical response based on the normalization of carbohydrate antigen 19-9 and by radiologic response based on size change at imaging.

RESULTS

The patients were classified into the following three groups based on their response to neoadjuvant chemotherapy and prognosis: biochemical responders (BR+), radiology-only responders (BR-/RR+), and non-responders (BR-/RR-). The 3-year overall survival rate was higher for BR+ (71.0%) than for BR-/RR+ (53.6%) or BR-/RR- (33.1%) (P < 0.001). Response to neoadjuvant chemotherapy also was identified as a significant risk factor for recurrence in a comparison between BR-/RR+ and BR+ (hazard ratio [HR], 2.15; 95% confidence interval [CI] 1.19-3.88; P = 0.011) and BR-/RR- (HR, 3.82; 95% CI 2.41-6.08; P < 0.001). Additionally, regardless of the response to neoadjuvant chemotherapy, patients who completed adjuvant chemotherapy had a significantly higher 3-year overall survival rate than those who did not.

CONCLUSIONS

This response evaluation criterion for neoadjuvant chemotherapy is feasible and can significantly predict prognosis. Additionally, completion of adjuvant chemotherapy could be helpful to patients who undergo neoadjuvant chemotherapy regardless of their response to neoadjuvant chemotherapy.

15-Year Experience of Distal Pancreatectomy with Celiac Axis Resection (DP-CAR) for Pancreatic Cancer-A Korean Nationwide Investigation

BACKGROUND

As systemic treatment for pancreatic cancer advances, distal pancreatectomy with celiac axis resection (DP-CAR) has been considered a curative-intent surgical option for advanced pancreatic cancer. This study aimed to review the surgical and oncologic outcomes of patients undergoing DP-CAR based on Korean nationwide data.

METHODS

We collected the data of patients who underwent DP-CAR for pancreatic cancer between 2007 and 2021 at seven major hospitals in Korea. The clinicopathological characteristics, postoperative complications, and data on the survival of the patients were retrospectively reviewed. Logistic regression analysis was performed to identify risk factors for postoperative complications and survival.

RESULTS

A total of 75 patients, consisting mainly of borderline resectable (n = 32) or locally advanced (n = 30) pancreatic cancer, were included in the analysis. Forty-two (56.0%) patients underwent neoadjuvant treatment (NAT). Twenty (26.7%) patients experienced Clavien-Dindo grade ≥ 3 complications, including four patients with ischemic gastropathy, two with hepatic ischemia, and two procedure-related mortalities. Neoadjuvant chemotherapy increased the risk of postoperative complications (p = 0.028). The median recurrence-free and overall survival were 7 and 19 months, with a 5-year survival rate of 13% and 24%, respectively. In the NAT group, a decrease in CA 19-9 and the post-NAT maximum standardized uptake value (SUVmax) in positron emission tomography were associated with survival after surgical resection.

CONCLUSIONS

Despite the possibility of major complications, DP-CAR could be a feasible option for achieving curative resection with fair survival outcomes in patients with borderline resectable or locally advanced pancreatic cancer. Further studies investigating the safety of the procedure and identifying proper surgical candidates with potential survival gains are necessary.

Reshaping the Pancreatic Cancer Microenvironment at Different Stages with Chemotherapy

The dynamic tumor microenvironment, especially the immune microenvironment, during the natural progression and/or chemotherapy treatment is a critical frontier in understanding the effects of chemotherapy on pancreatic cancer. Non-stratified pancreatic cancer patients always receive chemotherapeutic strategies, including neoadjuvant chemotherapy and adjuvant chemotherapy, predominantly according to their physical conditions and different disease stages. An increasing number of studies demonstrate that the pancreatic cancer tumor microenvironment could be reshaped by chemotherapy, an outcome caused by immunogenic cell death, selection and/or education of preponderant tumor clones, adaptive gene mutations, and induction of cytokines/chemokines. These outcomes could in turn impact the efficacy of chemotherapy, making it range from synergetic to resistant and even tumor-promoting. Under chemotherapeutic impact, the metastatic micro-structures in the primary tumor may be built to leak tumor cells into the lymph or blood vasculature, and micro-metastatic/recurrent niches rich in immunosuppressive cells may be recruited by cytokines and chemokines, which provide housing conditions for these circling tumor cells. An in-depth understanding of how chemotherapy reshapes the tumor microenvironment may lead to new therapeutic strategies to block its adverse tumor-promoting effects and prolong survival. In this review, reshaped pancreatic cancer tumor microenvironments due to chemotherapy were reflected mainly in immune cells, pancreatic cancer cells, and cancer-associated fibroblast cells, quantitatively, functionally, and spatially. Additionally, small molecule kinases and immune checkpoints participating in this remodeling process caused by chemotherapy are suggested to be blocked reasonably to synergize with chemotherapy.

Added value of digital FDG-PET/CT in disease staging and restaging in patients with resectable or borderline resectable pancreatic cancer

BACKGROUND

We studied the added value of digital FDG-PET/CT in disease staging and restaging compared to the standard work-up with contrast enhanced CT (ceCT) and CA19-9 in patients with resectable or borderline resectable pancreatic cancer who received neo-adjuvant therapy. Primary endpoints were tumor response compared to ceCT and CA19.9 as well as the ability to detect distant metastatic disease.

METHODS

35 patients were included in this dual-center prospective study. FDG-PET using digital photon counting technology combined with CT scans were acquired before (T1) and after neo-adjuvant therapy (T2). Patients were staged and restaged based on standard protocol with ceCT and CA 19.9, while all PET/CT scans were stored securely and not included in clinical decision making. After the pancreatic resection, an expert team retrospectively assessed the CT tumor diameter, CA19-9, tumor FDG-uptake, and appearance of metastatic disease of all patients for both time points.

RESULTS

CA19-9 levels, CT tumor diameter, and tumor FDG-uptake on PET significantly decreased from T1 to T2 (p = 0.017, p = 0.001, and p < 0.0001). The change in FDG-uptake values showed a strong positive correlation with the change in CT tumor diameter and change in CA19-9 (R = 0.75 and R = 0.73, respectively). In addition, small-volume liver lesions were detected on digital PET/CT in 5/35 patients (14%), 4 of which were pathology confirmed at laparotomy. Only one of these five cases was detected on baseline staging ceCT (3%).

CONCLUSION

We found that adding digital PET/CT strengthens restaging after neo-adjuvant therapy based on the observed strong correlation with ceCT tumor diameter and Ca19.9. Also, digital PET/CT was found to detect occult metastatic disease not visualized on ceCT, that would have resulted in altered disease staging and therapeutic strategy in a substantial proportion of patients.

Imaging Recommendations for Diagnosis, Staging, and Management of Pancreatic Cancer

Pancreatic cancer is the fourth most prevalent cause of cancer-related death worldwide, with a fatality rate equal to its incidence rate. Pancreatic cancer is a rare malignancy with a global incidence and death ranking of 14th and 7th, respectively. Pancreatic cancer cases are divided into three categories without metastatic disease: resectable, borderline resectable, or locally advanced disease. The category is determined by the tumor's location in the pancreas and whether it is abutting or encasing the adjacent arteries and/or vein/s.

The stage of disease and the location of the primary tumor determine the clinical presentation: the pancreatic head, neck, or uncinate process, the body or tail, or multifocal disease. Imaging plays a crucial role in the diagnosis and follow-up of pancreatic cancers. Various imaging modalities available for pancreatic imaging are ultrasonography (USG), contrast-enhanced computed tomography (CECT), magnetic resonance imaging (MRI), and 18-fluoro-deoxy glucose positron emission tomography (FDG PET).

Even though surgical resection is possible in both resectable and borderline resectable non-metastatic cases, neoadjuvant chemotherapy with or without radiotherapy has become the standard practice for borderline resectable cases as it gives a high yield of R0 resection.

Borderline Resectable Pancreatic Cancer: Challenges for Clinical Management

Background

Pancreatic ductal adenocarcinoma (PDAC) remains a significant worldwide health problem with a poor prognosis. A borderline resectable pancreatic ductal adenocarcinoma (BR-PDAC) is a tumor with limited vascular involvement that is technically resectable but with a high risk of positive margins (R1 resection).

Objective

To identify the current challenges that exist in the management of BR-PDAC.

Methods

A review of the literature was conducted to identify articles discussing the definitions and management of BR-PDAC.

Key Findings

Several anatomic definitions of BR-PDAC exist, and there is significant heterogeneity in their utilization across published trials. To improve the odds of a margin negative (R0) resection, a neoadjuvant treatment approach involving chemotherapy with or without radiation is currently preferred. While supporting the efficacy of a neoadjuvant approach in BR-PDAC, the largest published randomized trials have utilized older gemcitabine-based regimens. Recently published Phase II evidence and meta-analyses have supported the use of modern multi-agent regimens such as FOLFIRINOX. The utility of adding radiation to a chemotherapy backbone remains in question. Due to remnant fibrosis and edema following neoadjuvant therapy, accurately selecting patients for resection based on a restaging CT scan is challenging. Furthermore, the role of adjuvant therapy in BR-PDAC patients receiving neoadjuvant therapy needs to be defined.

Conclusion

Though progress has been made, the optimal management of BR-PDAC is uncertain. Phase III trials utilizing modern chemotherapeutic regimens are needed to establish a standard of care.

Correlation of Transcriptomics and FDG-PET SUVmax Indicates Reciprocal Expression of Stemness-Related Transcription Factor and Neuropeptide Signaling Pathways in Glucose Metabolism of Ewing Sarcoma

BACKGROUND

In Ewing sarcoma (EwS), long-term treatment effects and poor survival rates for relapsed or metastatic cases require individualization of therapy and the discovery of new treatment methods. Tumor glucose metabolic activity varies significantly between patients, and FDG-PET signals have been proposed as prognostic factors. However, the biological basis for the generally elevated but variable glucose metabolism in EwS is not well understood.

METHODS

We retrospectively included 19 EwS samples (17 patients). Affymetrix gene expression was correlated with maximal standardized uptake value (SUVmax) using machine learning, linear regression modelling, and gene set enrichment analyses for functional annotation.

RESULTS

Expression of five genes correlated (MYBL2, ELOVL2, NETO2) or anticorrelated (FAXDC2, PLSCR4) significantly with SUVmax (adjusted p-value ≤ 0.05). Additionally, we identified 23 genes with large SUVmax effect size, which were significantly enriched for "neuropeptide Y receptor activity (GO:0004983)" (adjusted p-value = 0.0007). The expression of the members of this signaling pathway (NPY, NPY1R, NPY5R) anticorrelated with SUVmax. In contrast, three transcription factors associated with maintaining stemness displayed enrichment of their target genes with higher SUVmax: RNF2, E2F family, and TCF3.

CONCLUSION

Our large-scale analysis examined comprehensively the correlations between transcriptomics and tumor glucose utilization. Based on our findings, we hypothesize that stemness may be associated with increased glucose uptake, whereas neuroectodermal differentiation may anticorrelate with glucose uptake.

FDG-PET Predicts Neoadjuvant Therapy Response and Survival in Borderline Resectable/Locally Advanced Pancreatic Adenocarcinoma

BACKGROUND

Neoadjuvant therapy (NAT) is used in borderline resectable/locally advanced (BR/LA) pancreatic ductal adenocarcinoma (PDAC). Anatomic imaging (CT/MRI) poorly predicts response, and biochemical (CA 19-9) markers are not useful (nonsecretors/nonelevated) in many patients. Pathologic response highly predicts survival post-NAT, but is only known postoperatively. Because metabolic imaging (FDG-PET) reveals primary tumor viability, this study aimed to evaluate our experience with preoperative FDG-PET in patients with BR/LA PDAC in predicting NAT response and survival.

METHODS

We reviewed all patients with resected BR/LA PDAC who underwent NAT with FDG-PET within 60 days of resection. Pre- and post-NAT metabolic (FDG-PET) and biochemical (CA 19-9) responses were dichotomized in addition to pathologic responses. We compared post-NAT metabolic and biochemical responses as preoperative predictors of pathologic responses and recurrence-free survival (RFS) and overall survival (OS).

RESULTS

We identified 202 eligible patients. Post-NAT, 58% of patients had optimization of CA 19-9 levels. Major metabolic and pathologic responses were present in 51% and 38% of patients, respectively. Median RFS and OS times were 21 and 48.7 months, respectively. Metabolic response was superior to biochemical response in predicting pathologic response (area under the curve, 0.86 vs 0.75; P<.001). Metabolic response was the only univariate preoperative predictor of OS (odds ratio, 0.25; 95% CI, 0.13-0.40), and was highly correlated (P=.001) with pathologic response as opposed to biochemical response alone. After multivariate adjustment, metabolic response was the single largest independent preoperative predictor (P<.001) for pathologic response (odds ratio, 43.2; 95% CI, 16.9-153.2), RFS (hazard ratio, 0.37; 95% CI, 0.2-0.6), and OS (hazard ratio, 0.21; 95% CI, 0.1-0.4).

CONCLUSIONS

Among patients with post-NAT resected BR/LA PDAC, FDG-PET highly predicts pathologic response and survival, superior to biochemical responses alone. Given the poor ability of anatomic imaging or biochemical markers to assess NAT responses in these patients, FDG-PET is a preoperative metric of NAT efficacy, thereby allowing potential therapeutic alterations and surgical treatment decisions. We suggest that FDG-PET should be an adjunct and recommended modality during the NAT phase of care for these patients.

Short-Course or Total Neoadjuvant Chemotherapy in Resectable and Borderline Resectable Pancreatic Cancer - Current Status and Future Perspectives

Neoadjuvant therapy improves overall survival compared with a surgery-first approach in patients with borderline resectable pancreatic cancer (BRPC). Evidence of higher quality is required to determine whether neoadjuvant therapy has potential benefits and improves survival for patients with resectable pancreatic cancer (RPC). Most randomized controlled trials (RCTs) have explored short-course neoadjuvant chemotherapy (SNT), but total neoadjuvant chemotherapy (TNT) is now the experimental arm of ongoing RCTs. This article reviews the current status of SNT and TNT in RPC and BRPC, and provides perspectives of future challenges and research directions in this field.

Surgical Management of Non-Metastatic Pancreatic Cancer in the United Kingdom: Results of a Nationwide Survey on Current Practice

BACKGROUND

It is presently unclear what clinical pathways are followed for patients with non-metastatic PDAC in specialised centres for pancreatic surgery across the United Kingdom (UK).

METHODS

Between August 2019 and August 2020 an electronic survey was conducted aiming at a national cohort of pancreatic surgeons in the UK. Participants replied to a list of standardised questions and clinical vignettes, and data were collected and analysed focusing on management preferences, resectability criteria, and contraindications to surgery.

RESULTS

Within the study period, 65 pancreatic surgeons from 27 specialist centres in the UK (96%) completed the survey. Multidisciplinary team meetings are utilised universally for the management of patients with PDAC, however, different staging systems for resectability classification are being applied. In borderline resectable PDAC, most surgeons were keen to proceed with surgical exploration post NAT, but differences were noted in preferred chemotherapy regimens. Surgeons from standard volume institutions performed fewer vein resections annually and were more likely to deem patients with locally advanced PDAC as unresectable. Intra-institutional variability in patient management was also present and ranging between 20-80%.

CONCLUSIONS

Significant variability in the surgical management of non-metastatic PDAC was identified both on inter- and intra-institutional level.