Results of surgery and adjuvant radiotherapy for pancreatic cancer

Molecular mechanisms of pancreatic cancer liver metastasis: the role of PAK2

Background

Pancreatic cancer remains an extremely malignant digestive tract tumor, posing a significant global public health burden. Patients with pancreatic cancer, once metastasis occurs, lose all hope of cure, and prognosis is extremely poor. It is important to investigate liver metastasis of Pancreatic cancer in depth, not just because it is the most common form of metastasis in pancreatic cancer, but also because it is crucial for treatment planning and prognosis assessment. This study aims to delve into the mechanisms of pancreatic cancer liver metastasis, with the goal of providing crucial scientific groundwork for the development of future treatment methods and drugs.

Methods

We explored the mechanisms of pancreatic cancer liver metastasis using single-cell sequencing data (GSE155698 and GSE154778) and bulk data (GSE71729, GSE19279, TCGA-PAAD). Initially, Seurat package was employed for single-cell data processing to obtain expression matrices for primary pancreatic cancer lesions and liver metastatic lesions. Subsequently, high-dimensional weighted gene co-expression network analysis (hdWGCNA) was used to identify genes associated with liver metastasis. Machine learning algorithms and COX regression models were employed to further screen genes related to patient prognosis. Informed by both biological understanding and the outcomes of algorithms, we meticulously identified the ultimate set of liver metastasis-related gene (LRG). In the study of LRG genes, various databases were utilized to validate their association with pancreatic cancer liver metastasis. In order to analyze the effects of these agents on tumor microenvironment, we conducted an in-depth analysis, including changes in signaling pathways (GSVA), cell differentiation (pseudo-temporal analysis), cell communication networks (cell communication analysis), and downstream transcription factors (transcription factor activity prediction). Additionally, drug sensitivity analysis and metabolic analysis were performed to reveal the effects of LRG on gemcitabine resistance and metabolic pathways. Finally, functional experiments were conducted by silencing the expression of LRG in PANC-1 and Bx-PC-3 cells to validate its influence to proliferation and invasiveness on PANC-1 and Bx-PC-3 cells.

Results

Through a series of algorithmic filters, we identified PAK2 as a key gene promoting pancreatic cancer liver metastasis. GSVA analysis elucidated the activation of the TGF-beta signaling pathway by PAK2 to promote the occurrence of liver metastasis. Pseudo-temporal analysis revealed a significant correlation between PAK2 expression and the lower differentiation status of pancreatic cancer cells. Cell communication analysis revealed that overexpression of PAK2 promotes communication between cancer cells and the tumor microenvironment. Transcription factor activity prediction displayed the transcription factor network regulated by PAK2. Drug sensitivity analysis and metabolic analysis revealed the impact of PAK2 on gemcitabine resistance and metabolic pathways. CCK8 experiments showed that silencing PAK2 led to a decrease in the proliferative capacity of pancreatic cancer cells and scratch experiments demonstrated that low expression of PAK2 decreased invasion capability in pancreatic cancer cells. Flow cytometry reveals that PAK2 significantly inhibited apoptosis in pancreatic cancer cell lines. Molecules related to the TGF-beta pathway decreased with the inhibition of PAK2, and there were corresponding significant changes in molecules associated with EMT.

Conclusion

PAK2 facilitated the angiogenic potential of cancer cells and promotes the epithelial-mesenchymal transition process by activating the TGF-beta signaling pathway. Simultaneously, it decreased the differentiation level of cancer cells, consequently enhancing their malignancy. Additionally, PAK2 fostered communication between cancer cells and the tumor microenvironment, augments cancer cell chemoresistance, and modulates energy metabolism pathways. In summary, PAK2 emerged as a pivotal gene orchestrating pancreatic cancer liver metastasis. Intervening in the expression of PAK2 may offer a promising therapeutic strategy for preventing liver metastasis of pancreatic cancer and improving its prognosis.

Place of hyperthermic intraperitoneal chemotherapy in the armament against pancreatic adenocarcinoma: A survival, mortality and morbidity systematic review

Pancreatic adenocarcinoma is one of the deadliest types of cancer worldwide, with a 5-year survival rate of 8% despite recent treatment advancements. The present systematic review aimed to investigate the role of hyperthermic intraperitoneal chemotherapy (HIPEC) following surgical resection for pancreatic adenocarcinoma, with or without peritoneal carcinomatosis. A systematic search of the MEDLINE and SCOPUS electronic databases was performed according to PRISMA guidelines. All possible relevant articles published between January 1980 and May 2019 were retrieved using multiple search terms associated with HIPEC and pancreatic adenocarcinoma. The initial search resulted in 1,244 reports, which condensed to 41 reports following screening of titles and abstracts, and subsequently to four reports following full-text thorough examination. The four reports included involved a prospective cohort study of HIPEC use in resectable pancreatic adenocarcinoma, and three retrospective studies of HIPEC use following cytoreductive surgery for peritoneal carcinomatosis due to pancreatic adenocarcinoma, resulting in a total of 47 patients. The overall survival ranged between 2 and 62 months, and the hospital mortality rate was 8.5%. Morbidity (34%) was mainly attributed to anastomotic leak or respiratory failure. Due to the small sample size and low quality of evidence of the included studies, no valid conclusions could be drawn. Therefore, further studies are required to justify the use of HIPEC as an adjuvant therapy in resectable pancreatic adenocarcinoma, while cytoreductive surgery and HIPEC in peritoneal carcinomatosis of pancreatic origin seems not only not useful but also unsafe at this level of evidence.

Improving Survival of Pancreatic Cancer. What Have We Learnt?

Pancreatic adenocarcinoma still ranks high among cancer-related deaths worldwide. In spite of substantial strides in preoperative staging, surgery, perioperative care, and adjuvant treatment, the survival still remains dismal. A number of patient-, disease-, and surgeon-related factors play a role in deciding the eventual outcome of the patient. The aim of this commentary is to review the current knowledge of various factors and the recent advances that impact the survival of patients with pancreatic adenocarcinoma. A search of scientific literature using Embase and MEDLINE, for the years 1985-2015, was carried out for search terms "pancreatic cancer" and "survival." Further search was based on the various specific prognostic factors that contribute towards survival of patients with pancreatic cancer found in the literature. Most of the studies used for this review include those that deal with pancreatic head cancers, some include patients with pancreatic cancers in all locations while very few included patients with tumors of body and tail only. In spite of significant developments in pre- and perioperative management, increased rates of margin-negative resections, and use of adjuvant treatment, the survival rates of pancreatic cancer patients remains poor. A paradigm shift with more effective adjuvant regimen and genetic interventions may help change the outcomes of patients with pancreatic cancer.

Sequential neoadjuvant chemoradiotherapy (CRT) followed by curative surgery vs. primary surgery alone for resectable, non-metastasized pancreatic adenocarcinoma: NEOPA- a randomized multicenter phase III study (NCT01900327, DRKS00003893, ISRCTN82191749)

BACKGROUND

Median OS after surgery in curative intent for non-metastasized pancreas cancer ranges under study conditions from 17.9 months to 23.6 months. Tumor recurrence occurs locally, at distant sites (liver, peritoneum, lungs), or both. Observational and autopsy series report local recurrence rates of up to 87% even after potentially "curative" R0 resection. To achieve better local control, neoadjuvant CRT has been suggested for preoperative tumour downsizing, to elevate the likelihood of curative, margin-negative R0 resection and to increase the OS rate. However, controlled, randomized trials addressing the impact of neoadjuvant CRT survival do not exist.

METHODS/DESIGN

The underlying hypothesis of this randomized, two-armed, open-label, multicenter, phase III trial is that neoadjuvant CRT increases the three-year overall survival by 12% compared to patients undergoing upfront surgery for resectable pancreatic cancer. A rigorous, standardized technique of histopathologically handling Whipple specimens will be applied at all participating centers. Overall, 410 patients (n=205 in each study arm) will be enrolled in the trial, taking into regard an expected drop out rate of 7% and allocated either to receive neoadjuvant CRT prior to surgery or to undergo surgery alone. Circumferential resection margin status, i.e. R0 and R1 rates, respectively, surgical resectability rate, local and distant disease-free and global survival, and first site of tumor recurrence constitute further essential endpoints of the trial.

DISCUSSION

For the first time, the NEOPA study investigates the impact of neoadjuvant CRT on survival of resectable pancreas head cancer in a prospectively randomized manner. The results of the study have the potential to change substantially the treatment regimen of pancreas cancer.

TRIAL REGISTRATION

Clinical Trial gov: NCT01900327, DRKS00003893, ISRCTN82191749.

An autopsy study to clarify characteristics of local recurrence after extended pancreatectomy with intraoperative radiation therapy in patients with pancreatic cancer

PURPOSE

Local relapses frequently occur even after curative resection of pancreatic cancer. To control local recurrence, we adopted extended radical resection combined with intraoperative radiation therapy.

METHODS

A retrospective review was conducted on 41 patients who underwent extended radical pancreatectomy combined with intraoperative radiation therapy for pancreatic cancer. Fourteen patients underwent autopsies. We took en bloc specimens of the abdominal aorta with surrounding connective tissue to evaluate histological characteristics of local status at autopsies.

RESULTS

Autopsies disclosed microscopic local recurrence in five (36%) of the 14 patients, although no evidence of local relapse was observed in either follow-up images or macroscopic findings at autopsy. Of the three patients with R1 resection, two had no local recurrence microscopically at autopsy. Histological features of local recurrence in autopsy samples showed small numbers of cancer cells surrounded by thick connective tissue without mass formation.

CONCLUSIONS

The autopsy study revealed that a characteristic of local recurrence after this treatment was tiny cancer cells scattered in dense connective tissue; these cells were undetected by follow-up imaging.

The pathology and genetics of metastatic pancreatic cancer

CONTEXT

Metastatic disease is the most critical determinant of resectability of pancreatic cancer and accounts for the poor outcome of patients with this disease. Thus, a better understanding of metastatic pancreatic cancer will afford new opportunities for therapeutic intervention.

OBJECTIVE

To summarize and discuss the current understanding of the clinical and molecular features of metastatic pancreatic cancer.

DATA SOURCES

Published literature on advanced stage pancreatic cancer, pancreatic cancer metastasis, and autopsy findings in patients with pancreatic cancer.

CONCLUSIONS

In the clinical setting, it can be difficult to distinguish a metastatic pancreatic carcinoma from primary neoplasms in the liver, lung, or ovary. However, immunolabeling for DPC4 protein as part of a diagnostic panel is useful for making this distinction. Emerging data from a variety of investigators now indicate that overexpression of EphA2, loss of DPC4 and MKK4, and aberrant activation of the Hedgehog signaling pathway are associated with metastatic propensity of pancreatic cancers, providing novel therapeutic targets for the most lethal stage of this disease.

Long-term outcomes of extended radical resection combined with intraoperative radiation therapy for pancreatic cancer

BACKGROUND/PURPOSE

Systemic and/or local recurrence often occurs even after curative resection for pancreatic cancer (PC). To prevent local relapse we adopted an extended radical resection combined with intraoperative radiation therapy in patients with PC, and all the patients were followed for more than 5 years.

METHODS

We assessed the long-term outcomes of 41 patients who underwent this combined therapy. The cumulative survival curve in this series was depicted using the Kaplan-Meier method. Statistical analyses were performed using the log-rank test.

RESULTS

The actual 5-year survival rate was 14.6%, with a median survival time of 17.6 months. Six patients have been 5-year survivors. Local recurrence occurred in only 2 patients (5.0%). Cancer-related death occurred in 32 patients, 18 of whom had liver metastases. The patients with liver metastases had a significantly shorter survival time than those with other cancer-related causes of death. Patients with n3 lymph node involvement, extrapancreatic nerve plexus invasion, and stage IV disease had significantly poorer prognoses than patients without these characteristics.

CONCLUSIONS

Our combined therapy for patients with PC contributed to local control; however, it provided no survival benefit, because of liver metastases.

Adjuvant therapy for pancreatic cancer: a review

Pancreatic cancer is uniformly fatal unless it can be surgically resected. Survival rates for the 15% to 20% of patients who have resectable disease, however, are a disappointing 10% to 30%, depending on the status of margins and surrounding lymph nodes. In the mid-1980s, a landmark study by the Gastrointestinal Tumor Study Group was the first to demonstrate a survival benefit from adjuvant therapy in the form of chemoradiation. Since then, several studies in both North America and Europe have tested the role of adjuvant chemotherapy or chemoradiation in pancreatic cancer, and the results have stirred great controversy. For this review, the evidence for adjuvant therapy in pancreatic cancer was examined, and the significant practice differences that exist between North American and European oncologists were highlighted. The authors investigated the results from the European Study Group for Pancreatic Cancer-1 trial and the reasons why that study has served to reinforce rather than resolve these trans-Atlantic differences. They also reviewed preliminary data from more recent adjuvant trials and explored the possible benefits of a neoadjuvant approach.

Final results of a prospective trial of a PEFG (Cisplatin, Epirubicin, 5-Fluorouracil, Gemcitabine) regimen followed by radiotherapy after curative surgery for pancreatic adenocarcinoma

BACKGROUND

Postoperative management of patients with pancreatic adenocarcinoma (PA) is controversial.

METHODS

The aim of this pilot study was to assess the feasibility of postoperative combination chemotherapy followed by radiotherapy in patients aged 18-70 years with a histological diagnosis of PA, and Karnofsky performance status (KPS) > or =70. Cisplatin and epirubicin 40 mg/m2 on day 1, gemcitabine 600 mg/m2 on day 1 and 8, and 5-fluorouracil 200 mg/m2/day as protracted infusion (PEFG regimen) were delivered every 28 days for 4 cycles. Assuming a minimum one-year disease-free survival (DFS) of interest of 65% and a maximum of low interest of 45% (alpha 0.05; beta 0.10), the target enrollment was 51 patients, and the strategy would be considered to deserve further analysis if more than 29 patients were DF at one-year from surgery.

RESULTS

Fifty-one patients, KPS >80: 29, median tumor size 3.5 cm, stage II/III/IVA: 2/34/13, grade 3-4: 22, positive resection margins: 26, node positive: 46, received 179 cycles of chemotherapy. Main grade 3/4 toxicity consisted of neutropenia (51%), thrombocytopenia (18%), and anemia (4%). One-year DFS was 67 +/- 7%. Two-year overall survival was 53 +/- 7%.

CONCLUSION

Postoperative management of PA with this multimodality strategy was well tolerated and yielded a promising outcome.

Prophylactic hepatic irradiation following curative resection of pancreatic cancer

BACKGROUND/PURPOSE

It is unlikely that adjuvant chemoradiotherapy applied to the pancreatic bed alone significantly improves the survival of patients with resectable pancreatic cancer. The aim of the present study was to determine whether prophylactic hepatic irradiation (PHI) improved patient outcome after the curative resection of pancreatic cancer.

METHODS

The study population was comprised of 34 patients (PHI group) who were administered PHI after curative resection of pancreatic cancer between September 1994 and December 2003. The whole liver was irradiated with a total dose of 19.8-22.0 Gy under continuous infusion of 5-fluorouracil. The cumulative rate of liver metastasis and the survival outcomes of the PHI group were compared with those of 31 patients without PHI (non-PHI group) who underwent curative resection of pancreatic cancer.

RESULTS

The planned PHI was completed for 32 of the 34 patients. Two patients developed complications that might have been PHI-related. One developed liver abscesses which were successfully managed by percutaneous drainage. The other died of liver failure without recurrence 11 months after the operation. The cumulative incidence of liver metastasis was significantly lower for the PHI group than the non-PHI group (P=0.0455). Patients in the PHI group also survived significantly longer compared to those in the non-PHI group (P=0.0002).

CONCLUSIONS

The present findings suggest that PHI is well tolerated and is a potentially effective treatment strategy after curative resection of pancreatic cancer, thereby providing the basis for a randomized controlled trial.

Conclusions from the European Study Group for Pancreatic Cancer adjuvant trial of chemoradiotherapy and chemotherapy for pancreatic cancer

Pancreatic ductal adenocarcinoma remains one of the most difficult cancers to treat. It is a tumor that tends to present late, and surgical resection is only possible in a minority of patients. After successful surgery, the prognosis is still relatively poor. Attempts at more radical pancreatic resections and extended lymphadenectomy, although feasible without excessive morbidity and mortality, have failed to produce any convincing improvement in survival. During the last few years, therefore, efforts have been directed toward the development of adjuvant therapies in an attempt to improve outcome. This article describes the main trials of adjuvant chemotherapy, chemoradiotherapy, and chemoradiotherapy with follow-on chemotherapy and presents the results of the European Study Group for Pancreatic Cancer (ESPAC) 1 trial and the status of the ESPAC 2 and 3 trials.

Adjuvant therapy for pancreatic cancer: an evolving paradigm

Pancreatic cancer is the fourth leading cause of death in men and fifth in women in the United States. The median survival is 8 to 12 months for patients with locally advanced and unresectable disease and only 3 to 6 months for those with metastatic disease at presentation. Surgical resection offers the only potentially curative treatment. However, only 15% to 20% of patients present with tumors amenable to resection at initial diagnosis. Even for those who undergo resection, the prognosis remains poor. The 5-year survival following pancreaticoduodenectomy is only about 25% to 30% for node-negative tumors and 10% for node-positive tumors. Because of the dismal outcome for patients with resectable pancreatic cancer, adjuvant therapy has been administered in an attempt to improve the local control and overall survival. This review highlights historic and current perspectives of adjuvant therapy in resected pancreatic cancer.

Intraoperative radiation therapy for pancreatic adenocarcinoma: the Komagome hospital experience

We analyzed 144 patients with pancreatic adenocarcinoma who had received intraoperative radiation therapy (IORT) in combination with external beam radiation therapy (EBRT) within the past 20 years. The patients were divided into 2 groups: group 1 contained 65 patients with locally unresectable tumors who underwent bypass operations and group 2 contained 68 patients with resectable tumors who underwent pancreatic resection. As a pilot study, we performed additional arterial infusion chemotherapy after changing peripancreatic hemodynamics during EBRT in the remaining 11 patients. The 30 patients who received R0 resection had the best survival rates (3-year survival rate of 35.4%), while 3 patients with stage III disease survived more than 5 years. The survival of group 1 patients nearly equaled that of group 2 patients who underwent R1 or R2 resection (median survival, 10.9 vs. 11.1 months, respectively; P = 0.43). The 1-year survival rate for the 11 patients receiving arterial infusion chemotherapy was 45.4%, and 5 patients survived over 1 year without developing hepatic metastasis or regrowth of primary tumors. The survival benefits obtained using this form of radiotherapy are apparently limited. On the other hand, additional arterial infusion chemotherapy employing a new drug delivery system using hemodynamic change does appear promising.

Adjuvant therapy in pancreatic cancer: historical and current perspectives

The results from pancreatic ductal adenocarcinoma appear to be improving with increased resection rates and reduced postoperative mortality reported by specialist pancreatic cancer teams. Developments with medical oncological treatments have been difficult, however, due to the fundamentally aggressive biological nature of pancreatic cancer and its resistance to chemotherapy coupled with a relative dearth of randomised controlled trials. The European Study Group for Pancreatic Cancer (ESPAC)-1 trial recruited nearly 600 patients and is the largest trial in pancreatic cancer. The results demonstrated that the current best adjuvant treatment is chemotherapy using bolus 5-fluorouracil with folinic acid. The median survival of patients randomly assigned to chemoradiotherapy was 15.5 months and is comparable with many other studies, but the median survival in the chemotherapy arm was 19.7 months and is as good or superior to multimodality treatments including intra-operative radiotherapy, adjuvant chemoradiotherapy and neo-adjuvant therapies. The use of adjuvant 5-fluorouracil with folinic acid may be supplanted by gemcitabine but requires confirmation by ongoing clinical trials, notably ESPAC-3, which plans to recruit 990 patients from Europe, Canada and Australasia. Major trials such as ESPAC-1 and ESPAC-3 have set new standards for the development of adjuvant treatment and it is now clear that such treatment in this field has the potential to significantly improve both patient survival and quality of life after curative resection.

Adjuvant radiotherapy in resectable pancreatic carcinoma

AIM

Pancreatic cancer is a near fatal disease. External beam radiotherapy and intraoperative radiation therapy (IORT) has been proposed with the aim to improve clinical outcome in resectable tumors. The aim of this study is to assess the feasibility and outcome in patients with cT1-3 pancreatic cancer, treated with surgery, external beam radiotherapy and IORT.

METHODS

From 1990 to 1996, 17 patients with clinical stage T1-3N0-1M0 adenocarcinoma of the head of the pancreas were treated with pancreatectomy and pre- (nine patients: 5 Gy), intra- (all patients: 10 Gy) and post-operative (all patients: 50 Gy) radiotherapy. The pathologic T stages were: 4 pT2 and 13 pT3. The pathologic N stages were: 9 pN0 and 8 pN1. Minimum follow-up in living patients was 60 months.

RESULTS

No perioperative mortalities were recorded. Two patients showed postoperative morbidity (11.8%) which required a subsequent laparotomy. The disease-free survival at 1, 3 and 5 years was 41, 23 and 18%, respectively (median: 9 months). The overall survival at 1, 3 and 5 years was 70%, 41% and 18%, respectively (median: 17.5 months). Three patients developed local failure (17.6%) and 12 patients showed distant metastases (70.6%). Univariate analysis (logrank) showed: a significant correlation between both N-stage and retroperitoneal involvement (RPI) with local control (N-stage: P=0.0155; RPI:P =0.0295), a significant correlation between maximum tumor size and metastases-free survival (P=0.0167) and overall survival (P=0.0241); the female gender was another predictor of prolonged survival (P= 0.0465). Multivariate analysis (Cox) showed a significant impact of N-stage and retroperitoneal involvement on local control and also a significant correlation between perineural involvement and tumor diameter with metastases-free survival.

CONCLUSIONS

These results are similar to those of other published series and suggest that this approach is feasible with acceptable local control and survival, especially in patients with small tumors (<2.5 cm: 5 year survival=33.3%) and in female patients (5 year survival=30%). Due to the impact of gender, tumor diameter and N stage on prognosis, in the design of future trials a stratification of patients based on these categories should be considered. The search of effective chemotherapeutic agents is required, to reduce the high incidence of distant metastases, especially in larger tumors.

The role of adjuvant therapy for pancreatic cancer

Patients with pancreatic cancer have a very poor outlook. There have been major advances in the standard surgical treatment of this disease, resulting in decreased post-operative mortality and morbidity. The use of chemotherapy and radiotherapy has been developed to increase long-term patient survival following potentially curative resection. The standard chemotherapeutic agent is 5-fluorouracil (5-FU), although newer cytotoxic agents are in clinical trials for advanced cancer. Initial studies of adjuvant therapy have been based on small numbers of patients, but recently two large European randomised controlled trials of adjuvant therapy (EORTC and ESPAC-1) have been completed. These suggest that adjuvant chemotherapy has a significant survival advantage over resection alone but chemoradiotherapy does not. Promising new agents are being developed and tested mainly in clinical trials of advanced pancreatic cancer. The results of large-scale randomised controlled trials to assess adjuvant therapies for pancreatic cancer demonstrate the great surgical and oncological progress that has been made over the past decade.

Adjuvant therapy in pancreatic cancer

The outlook for patients with pancreatic cancer has been grim. There have been major advances in the surgical treatment of pancreatic cancer, leading to a dramatic reduction in post-operative mortality from the development of high volume specialized centres. This stimulated the study of adjuvant and neoadjuvant treatments in pancreatic cancer including chemoradiotherapy and chemotherapy. Initial protocols have been based on the original but rather small GITSG study first reported in 1985. There have been two large European trials totalling over 600 patients (EORTC and ESPAC-1) that do not support the use of chemoradiation as adjuvant therapy. A second major finding from the ESPAC-1 trial (541 patients randomized) was some but not conclusive evidence for a survival benefit associated with chemotherapy. A third major finding from the ESPAC-1 trial was that the quality of life was not affected by the use of adjuvant treatments compared to surgery alone. The ESPAC-3 trial aims to assess the definitive use of adjuvant chemotherapy in a randomized controlled trial of 990 patients.