K-ras point mutation in the nerve plexuses around the superior mesenteric artery in resectable adenocarcinoma of the pancreatic head: distribution pattern and related factors

Anatomy of the neural fibers at the superior mesenteric artery-a cadaver study

PURPOSE

Most surgeons perform right-sided semicircular clearance of the superior mesenteric artery (SMA) nerve plexus for pancreatic head carcinoma, presuming a linear course of the SMA nerve fibers. The hypothesis was that the SMA nerve plexus fibers follow a non-linear course, and the goal of the present study was to assess the neural fibers distribution along the SMA.

METHODS

The course of neural fibers along the retropancreatic and suprapancreatic SMA was assessed in 7 cadavers.

RESULTS

In the retropancreatic course of the vessel, the main nerve cords branch and form a large number of finer nerve branches performing an anti-clockwise rotation of slightly less than 90° around the SMA. Finer nerve branches are located rather close to the vessel, while the main nerve cords are localized in the loose connective tissue of the peripheral parts of the vascular sheath. Nerve fibers around the suprapancreatic SMA run as two main nerve cords framing the artery on the right lateral-ventral and the left lateral to lateral-dorsal side.

CONCLUSION

The rotation of the nerve fiber around the SMA indicates that a more radical resection of at least 180° of neural tissue around the SMA might be required to achieve tumor clearance in pancreatic cancer with perineural invasion at the uncinate margin.

Safety, Diagnostic Accuracy, and Effects of Endoscopic Ultrasound Fine-Needle Aspiration on Detection of Extravascular Migratory Metastases

BACKGROUND & AIMS

Tumor cells can migrate via diminutive perivascular cuffing to distant sites along blood vessels to form extravascular migratory metastases (EVMM). These metastases usually are identified during surgery or autopsies. We aimed to evaluate the feasibility and safety of endoscopic ultrasound fine-needle aspiration (EUS-FNA) of perivascular soft-tissue cuffs to detect EVMM. We compared findings from EUS with those from noninvasive cross-sectional imaging (reference standard) of patients who underwent EUS-FNA to assess suspected EVMM and studied the effects on pancreatic tumor staging and determination of resectability.

METHODS

We performed a retrospective analysis of 253 patients (mean age, 62 ± 12 y) who underwent EUS-FNA of 267 vessels for evaluation of suspected EVMM, from April 2001 through May 2018. EUS findings were compared with those from computed tomography (CT) and magnetic resonance imaging (MRI) as the reference standard. Lesions were considered to be malignant based on cytology analysis of FNA samples, histology analyses of surgical or biopsy specimens, or vascular abnormalities detected by CT or MRI that clearly indicate EVMM.

RESULTS

Thirty patients were found to have benign lesions. The remaining 223 patients who had malignancies (166 with pancreatic ductal adenocarcinomas [PDACs]), underwent further analyses. A median of 4 FNAs (range, 1-20 FNAs) were obtained from 4-mm perivascular soft-tissue cuffs (range, 2-20 mm). FNA and cytology analysis showed malignant cells in 163 vessels (69.4%) from 157 patients (70.4%). CT or MRI did not detect EVMM in 44 patients (28%) with malignancies, including 24 patients (24%) with newly diagnosed PDAC. Detection of EVMM by EUS-FNA resulted in upstaging of 15 patients and conversion of 14 patients with PDAC from resectable (based on CT or MRI) to unresectable. No adverse events were reported during a follow-up period of 3.9 months (range, 0-117 mo).

CONCLUSIONS

EUS-FNA and cytologic analysis of perivascular soft-tissue cuffs can detect EVMM that were not found in 28% of patients by CT or MRI. Detection of EVMM affects tumor staging and determination of tumor resectability.

Prediction of Recurrence With KRAS Mutational Burden Using Ultrasensitive Digital Polymerase Chain Reaction of Radial Resection Margin of Resected Pancreatic Ductal Adenocarcinoma

OBJECTIVE

Although complete surgical resection is the only curative method for pancreatic cancer, the radial resection margins of pylorus-preserving pancreaticoduodenectomy specimens might be underevaluated.

METHODS

KRAS mutation was assessed with droplet digital polymerase chain reaction on cells collected from the radial resection margins of 81 patients, and the results were compared with those of conventional pathologic resection margin (pRM) evaluation.

RESULTS

KRAS mutation was detected in 76 patients (94%), and molecular resection margin (mRM) positivity defined by a KRAS mutation rate of 4.19% or greater was observed in 18 patients (22%). Patients with mRM-positive had significantly worse recurrence-free survival (RFS) than those with mRM-negative in entire groups (P = 0.008) and in subgroups without chemotherapy or radiation therapy (all, P < 0.001). When combined pRMs-mRMs were evaluated, patients with combined pRM-mRM-positive (either pRM- or mRM-positive) had significantly worse RFS than those with combined resection margin-negative (both pRM and mRM negative) by univariate (P = 0.002) and multivariate (P = 0.03) analyses.

CONCLUSIONS

KRAS mutational analysis with ultrasensitive droplet digital polymerase chain reaction of the radial resection margin in pancreatic cancer patients who underwent pylorus-preserving pancreaticoduodenectomy can provide more accurate information on RFS by using alone or in combination with conventional pRM evaluation, especially in patients without chemotherapy or radiation therapy.

Dissected peripancreatic tissue margin is a critical prognostic factor and is associated with a K-ras gene mutation in pancreatic ductal adenocarcinoma

We previously reported that the dissected pancreatic tissue margin (DPM) and the preoperative serum level of carbohydrate antigen 19-9 (preCA19-9) were independent prognostic factors in pancreatic ductal adenocarcinoma (PDAC). In the current study, the prognostic relevance of these factors, including their molecular associations, were validated. A total of 161 patients with PDAC underwent a pancreatectomy between 1986 and 2013, and a multivariate Cox proportional hazards model and a propensity score-based model validated the prognostic importance of DPM. The prognostic factors were compared with the mutation profiles of the K-ras and TP53 genes. Univariate prognostic analysis of disease-specific survival (DSS) demonstrated that DPM (P<0.0001), preCA19-9 (P<0.0001) and Union for International Cancer Control (UICC) stage (P<0.0001), were all significantly associated with poor outcome in PDAC. A multivariate Cox proportional hazards model confirmed that preCA19-9 (P=0.0002) and DPM (P=0.0002) remained as prognostic factors independent of UICC stage (P=0.0015). The combination of preCA19-9 and DPM to predict prognosis could accurately identify the long-term survivors of PDAC (70% 5-year DSS), and a multivariate logistic regression model identified that DPM was the most effective predictor of mortality. The prognostic relevance of DPM was also confirmed (P=0.0008) through propensity score-based background adjustment of patient bias. K-ras gene mutation was significantly associated with DPM (P=0.0002), and DPM-positive patients demonstrated recurrence of distant metastasis in 67% of cases. Therefore, DPM is a critical prognostic indicator in PDAC. In combination with preCA19-9, DPM may be useful to identify long-term survivors of PDAC. Furthermore, to the best of our knowledge, the current study was the first to discover that DPM can represent a poor prognosis based putatively on its association with the K-ras gene mutation.

Cancer cells with p53 deletion detected by fluorescent in situ hybridization in peritoneal drainage fluid is correlated with early peritoneal seeding in resectable pancreatic cancer

Purpose

Free tumor cells in peritoneal fluid in patients with pancreatic cancer may have prognostic significance but there are few reports on methods for the effective detection of free tumor cells. The aims of this study were to identify free cancer cells in peritoneal fluid with fluorescent in situ hybridization (FISH) technique and to investigate its prognostic significance.

Methods

Twenty-eight patients with resectable pancreatic cancer who underwent surgical resection were included. Peritoneal washing and peritoneal drainage fluid were examined by FISH for p53 deletion.

Results

Among the study subjects, the R0 resection rate was 75%. None of the patients had positive cytology with Papanicolaou's method. p53 deletion was detected in 9 peritoneal washings (32.1%) and in 5 peritoneal drainage fluids (17.9%). After a median of 18 months of follow-up, 25 patients (89.3%) experienced recurrence and 14 patients (50.0%) had peritoneal seeding. Patients with p53 deletion detected in the peritoneal drainage fluid had positive radial margin (60.0% vs. 17.4%, P = 0.046) more frequently and a lower peritoneal metastasis free survival (median, 11.1 months vs. 30.3 months; P = 0.030). Curative resection (P < 0.001) and p53 deletion in peritoneal drainage fluid (P = 0.030) were independent risk factors of peritoneal metastasis free survival after multivariate analysis.

Conclusion

FISH technique detects free cancer cells with higher sensitivity compared to Papanicolaou's method. p53 deletion detected in peritoneal drainage fluid is correlated with positive radial resection margin and results in early peritoneal seeding. Patients with p53 deletion in peritoneal drainage fluid need more aggressive adjuvant treatment.

Redefining resection margin status in pancreatic cancer

Curative resection is crucial to survival in pancreatic cancer; however, despite optimization and standardization of surgical procedures, this is not always achieved. This review highlights that the rates of microscopic margin involvement (R1) vary markedly between studies and, although resection margin status is believed to be a key prognostic factor, the rates of margin involvement and local tumour recurrence or overall survival of pancreatic cancer patients are often incongruent. Recent studies indicate that the discrepancy between margin status and clinical outcome is caused by frequent underreporting of microscopic margin involvement. Lack of standardization of pathological examination, confusing nomenclature and controversy regarding the definition of microscopic margin involvement have resulted in the wide variation of reported R1 rates that precludes meaningful comparison of data and clinicopathological correlation.

Endoscopic ultrasound fine-needle aspiration detection of extravascular migratory metastasis from a remotely located pancreatic cancer

BACKGROUND & AIMS

Tumor cell migration along the periphery of blood vessels to remote sites has been termed extravascular migratory metastasis, which is distinct from direct gross tumor infiltration of blood vessels and from intravascular dissemination. Our objective was to report the presence of malignant perivascular cuffing of the celiac axis in a patient with an apparently early T stage and resectable pancreatic cancer.

METHODS

Case report is presented.

RESULTS

Endoscopic ultrasound (EUS) examination was performed with targeted fine-needle aspiration (FNA) of previously unrecognized perivascular cuffing by computed tomography, which established the presence of celiac axis malignant perivascular cuffing in the setting of a T1 pancreatic cancer.

CONCLUSIONS

EUS FNA might allow identification and tissue confirmation of otherwise unrecognized extravascular migratory metastasis. This finding suggests the potential for EUS FNA to further improve pancreatic cancer staging and to enhance patient care and outcomes.

Surgical management of carcinoma of the head of pancreas: extended lymphadenectomy or modified en bloc resection?

Pancreatoduodenectomy for the treatment of periampullary cancer was described over 70 years ago. The technique has evolved in an attempt to improve the dismal prognosis for patients with pancreatic cancers. Radical regional resection has been proposed to decrease the incidence of local recurrence as well as to improve survival. These extended resections have failed to show a significant survival benefit in prospective randomized controlled studies. Furthermore, extended pancreatic resections may be associated with increased morbidity. The concept of modified en bloc resection has been advocated and is soundly based on anatomical and pathological principals. This procedure is a modification of the radical regional resection previously described. It involves resection of the peripancreatic retroperitoneal tissue and lymph nodes en bloc with the head of pancreas, in order to achieve an R0 resection but without the morbidity associated with an extended lymphadenectomy. Conceptually, this procedure may be the most appropriate technique for the management of pancreatic head cancers although the ultimate effect on long-term survival can only be judged after further clinical studies.

Pancreatic cancer--low survival rates

INTRODUCTION

Cancers of the pancreas are identified in 11 800 to 13 500 patients each year in Germany. Epidemiological studies prove smoking and chronic alcohol consumption as causes of about 30% of pancreatic cancers.

METHODS

Selective literature review.

RESULTS

Only patients within TNM stage I and II have after oncologic tumor extirpation a chance for long term survival. Controlled prospective clinical trials demonstrated adjuvant chemotherapy yielding an additional significant survival benefit. The 3- and 5-year-survival after R0-resection and adjuvant chemotherapy are about 30% and below 15% respectively. Using the criteria of observed 5-year-survival less than 2% of all pancreatic cancer patients are alive. After R0-resection the median survival time is between 17 and 28 months, after R1/2-resection between 8 and 22 months.

DISCUSSION

Pancreatic cancer is even today for more than 95% of the patients incurable. Strategies to prevent pancreatic cancer are intended to stop smoking and chronic alcohol consumption and early surgical extirpation of cystic neoplastic lesions. For patients with established pancreatic cancer risk a follow-up protocol is discussed.

Resection margins and R1 rates in pancreatic cancer--are we there yet?

The prognosis of pancreatic cancer is poor, even for those patients who undergo surgical resection. The rate of local recurrence is high, despite the fact that in most series complete ('R0') resection is reported to be achieved in the majority of patients. The discrepancy between pathological assessment and clinical outcome indicates that microscopic margin involvement (R1) is frequently underreported, and potential causes for this are discussed in this review. Special emphasis is given to the variation that exists between currently used dissection techniques and their impact on the assessment of the resection margins in pancreatoduodenectomy specimens.

New advances in pancreatic surgery

PURPOSE OF REVIEW

New understanding of the dynamic of acute pancreatitis, the clinical impact of local pathology in chronic pancreatitis and cystic neoplastic lesions bearing high potential for malignant transformation has changed the management of pancreatic diseases.

RECENT FINDINGS

In acute pancreatitis, risk factors independently determining outcome in severe acute pancreatitis are early and persistent multiorgan failure, infected necrosis and extended sterile necrosis. The management of severe acute pancreatitis is based on early intensive-care treatment and late surgical debridement. In chronic pancreatitis, recent data from randomized controlled clinical trials have demonstrated duodenum-preserving pancreatic head resection with an inflammatory mass of the head as superior to pylorus-preserving Whipple resection. Cystic neoplasms are local lesions of the pancreas with high malignant potential. Local organ-preserving resection techniques have been applied with low morbidity and mortality, replacing a Whipple-type resection. Resection of pancreatic cancer is ineffective to cure patients. After an R0-resection, a significant survival benefit has been achieved when adjuvant chemotherapy has additionally been applied.

SUMMARY

New knowledge about the nature of inflammatory diseases, cystic neoplastic lesions and malignant pancreatic tumours has changed the indication for surgical treatment and the application of organ-preserving surgical techniques.

Modified extended pancreatoduodenectomy: en bloc resection of the peripancreatic retroperitoneal tissue and the head of pancreas

Malignant periampullary tumours often invade into retroperitoneal peripancreatic tissues and a positive resection margin following pancreatoduodenectomy is associated with a poor survival. For complete extirpation of the tumour, en bloc resection of the pancreatic head with all retroperitoneal peripancreatic tissue is essential to achieve negative resection margin. A modified radical pancreatoduodenectomy technique that aims to resect all peripancreatic retroperitoneal tissue en bloc with the head of the pancreas is described. We have used this new technique in the last 30 consecutive cases of pancreatoduodenectomy with excellent results as presented in this paper. This technique allows complete en bloc resection of retroperitoneal peripancreatic tissues while preserving normal functional tissue. This technique's advantage is that the resection can be carried out without breaching the retroperitoneal tumour extension plane, thereby minimizing tumour cell spillage.

Outcome of paraaortic node-positive pancreatic head and bile duct adenocarcinoma

BACKGROUND

This retrospective study aimed to identify the clinicopathologic features and surgical results of paraaortic node-positive periampullary adenocarcinoma.

METHODS

Between 1995 and 1999, 101 patients underwent pancreatectomy with regional and paraaortic lymphadenectomy. Fifteen (15%) patients had histologically proven paraaortic lymph node disease.

RESULTS

The 15 patients included 9 (26%) of 34 patients with pancreatic head carcinoma and 6 (17%) of 36 patients with bile duct adenocarcinoma. All 15 patients had locally advanced tumor invading adjacent structures. The 1-, 2-, and 3-year survival rates were 33%, 27%, and 0%, with median survival of 12 months (range 3 to 33). In patients with pancreatic head carcinoma or bile duct adenocarcinoma, survival curve for those without paraaortic lymph node metastasis was significantly better than that for those with involved paraaortic lymph nodes (P = 0.0033 or P = 0.0149).

CONCLUSIONS

When the paraaortic lymph nodes obtained from sampling biopsy are histologically positive, radical pancreatectomy with extended lymphatic and soft tissue clearance should be abandoned owing to poor outcome.

Treatment of pancreatic cancer: challenge of the facts

Adenocarcinoma of the pancreas is associated with the worst survival of any form of gastrointestinal malignancy. In spite of the progress in surgical treatment, resulting in increasing resection rates and a decrease in treatment-related morbidity and mortality, the true figures of cure are even today below 3%. The dissemination of pancreatic cancer behind the local tissue compartments restricts the short-term (< 3 years) and long-term outcome for patients who have undergone resection. By histological evaluation, less than 15% of the patients undergoing R(0) resection have a pN(0) status, more than 60% suffer from lymph angiosis carcinomatosa, and more than 50% suffer extrapancreatic nerve plexus infiltration. Hematoxylin and eosin-negative lymph nodes were found to be cancer positive when reverse transcriptase polymerase chain reaction (RT- PCR) or immunostaining was applied to the HE-negative lymph nodes. Cancer of the uncinate process has a very poor prognosis because there are no early symptoms; vessel wall involvement occurs early and frequently; a high association of liver metastasis exists as well. Surgery offers a low success rate, but it provides the only chance of cure. Ductal pancreatic cancer is diagnosed in more than 95% of the cases in an advanced stage; potentially curative resection can be performed only in about 10%-15% of these patients. Major contributions of surgery to improved treatment results are the reduction of surgical morbidity--e.g., early postoperative local and systemic complications--and a decrease of hospital mortality below 3%-5%. In most recently published prospective trials, R(0) resection has been reported to result in an increase in short-term survival beyond that recorded for patients with residual tumor. However, R(0) resection fails to improve long-term survival. In many published R(0) series, standard tissue resection of pancreatic head cancer with the Kausch-Whipple procedure failed to include remote cancer cell-positive tissues in the operative specimen; e.g., N(2)-lymph nodes, nerve plexus, and perivascular extrapancreatic and retropancreatic tissues were not excised. Cancer recurrence after so-called R(0) resection with curative intent is frequently the consequence of cancer left behind. Thus, long-term survival (> 5 years) is observed in a very small group of patients, contradicting the published 5-year actuarial survival rates of 20%-45% for resected patients. The assessment of clinical benefit from surgical or medical cancer treatment should therefore be based on several end points, not only on actuarial survival. Publication of actuarial survival figures must include the number of observed (actual) survivals, the definition of the subset of patients followed after resection, and the total number of patients in the study group; anything less is misleading. In reporting pancreatic cancer treatment trial results after oncological resections, more convincing primary end points to evaluate treatment efficacy are median survival (in months), actual survival at 1-5 years, and progression-free survival (in months). In series with multimodality treatment, clinical benefit response as well as quality of life measurements using the EORTC Quality of Life index C30 (QLQ-C30) are of importance in evaluating survival data. Adjuvant treatment improves survival after oncological resection; however, the short-term and long-term benefit after adjuvant chemotherapy in R(0) as well as in R(1)-(2) resected patients has not yet been underscored by data from controlled clinical trials. The survival benefit (median survival time) of adjuvant chemotherapy or radiochemotherapy has been demonstrated to be 6-10 months. Therefore, after oncological resection of pancreatic cancer each patient should be offered adjuvant treatment. A neoadjuvant treatment protocol for pancreatic cancer, however, has not been established.

Postoperative cytology for drained fluid from the pancreatic bed after "curative" resection of pancreatic cancers: does it predict both the patient's prognosis and the site of cancer recurrence?

OBJECTIVE

To evaluate the postoperative cytology of drained fluid from the pancreatic bed as a predictive indicator of local recurrence after curative (R0) resection of pancreatic cancer.

SUMMARY BACKGROUND DATA

The pancreatic bed offers a common site of cancer recurrence (local recurrence), even after curative (R0) resection is performed for pancreatic cancer. If local recurrence is thereby predicted precisely, soon after surgery, we have a chance to treat it by adding radiation or some other locoregional therapy before it can grow or spread beyond the pancreatic bed. However, there have been no previous reports of cytology performed on the drained fluid after pancreatectomy.

METHODS

This study includes 94 patients who had shown negative results in the peritoneal washing cytology before resection and subsequently received pancreatectomies for pancreatic tumors. They consisted of 12 benign tumors, 17 noninvasive or minimally invasive carcinomas and 65 invasive ductal carcinomas (R0 = 58; R1/2 = 7). Postoperatively, the drained fluid from the pancreatic bed was collected for 24 hours and used for cytologic examination. The cytologic results were examined in association with the histopathology of the resected tumor, patient's survival, and mode of cancer recurrence, including local recurrence.

RESULTS

Patients with benign tumors or noninvasive/minimally invasive carcinomas had negative result in cytology, and none of them have died of local recurrence (limited to the pancreatic bed) to date. However, patients with invasive ductal carcinoma revealed higher cytology-positive rates: 28% (16/58) in curative (R0) resection; and 71% (5/7) in noncurative (R1/2) resection. Among 58 patients with R0 resection, the 3-year survival rate was 14% in 16 cytology-positive patients and 55% in 42 cytology-negative patients (P < 0.05). The 3-year cumulative rate of local recurrence was 85% and 23%, respectively (P < 0.05). Compared with other histopathologic parameters obtained from the resected specimens, the drain cytology was more specific in predicting the subsequent development of local recurrence.

CONCLUSIONS

Drain-cytology was a quick examination that enabled us to specifically indicate both minute residual cancer and subsequent development of local recurrence even after R0 resection of pancreatic cancer.