Influence of Klebsiella pneumoniae and quinolone treatment on prognosis in patients with pancreatic cancer

BACKGROUND

An increasing body of evidence suggests that microbiota may promote progression of pancreatic ductal adenocarcinoma (PDAC). It was hypothesized that gammaproteobacteria (such as Klebsiella pneumoniae) influence survival in PDAC, and that quinolone treatment may attenuate this effect.

METHODS

This was a retrospective study of patients from the Massachusetts General Hospital (USA) and Ludwig-Maximilians-University (Germany) who underwent preoperative treatment and pancreatoduodenectomy for locally advanced or borderline resectable PDAC between January 2007 and December 2017, and for whom a bile culture was available. Associations between tumour characteristics, survival data, antibiotic use and results of intraoperative bile cultures were investigated. Survival was analysed using Kaplan-Meier curves and Cox regression analysis.

RESULTS

Analysis of a total of 211 patients revealed that an increasing number of pathogen species found in intraoperative bile cultures was associated with a decrease in progression-free survival (PFS) (-1·9 (95 per cent c.i. -3·3 to -0·5) months per species; P = 0·009). Adjuvant treatment with gemcitabine improved PFS in patients who were negative for K. pneumoniae (26·2 versus 15·3 months; P = 0·039), but not in those who tested positive (19·5 versus 13·2 months; P = 0·137). Quinolone treatment was associated with improved median overall survival (OS) independent of K. pneumoniae status (48·8 versus 26·2 months; P = 0·006) and among those who tested positive for K. pneumoniae (median not reached versus 18·8 months; P = 0·028). Patients with quinolone-resistant K. pneumoniae had shorter PFS than those with quinolone-sensitive K. pneumoniae (9·1 versus 18·8 months; P = 0·001).

CONCLUSION

K. pneumoniae may promote chemoresistance to adjuvant gemcitabine, and quinolone treatment is associated with improved survival.

Risk of malignancy in small pancreatic cysts decreases over time

BACKGROUND

Pancreatic cysts <15 mm without worrisome features have practically no risk of malignancy at the time of diagnosis but this can change over time. Optimal duration of follow-up is a matter of debate. We evaluated predictors of malignancy and attempted to identify a time to safely discontinue surveillance.

METHODS

Bi-centric study utilizing prospectively collected databases of patients with pancreatic cysts measuring <15 mm and without worrisome features who underwent surveillance at the Massachusetts General Hospital (1988-2017) and at the University of Verona Hospital Trust (2000-2016). The risk of malignant transformation was assessed using the Kaplan-Meier method and parametric survival models, and predictors of malignancy were evaluated using Cox regression.

RESULTS

806 patients were identified. Median follow-up was 58 months (6-347). Over time, 58 (7.2%) cysts were resected and of those, 11 had high grade dysplasia (HGD) or invasive cancer. Three additional patients had unresectable cancer for a total rate of malignancy of 1.7%. Predictors of development of malignancy included an increase in size ≥2.5 mm/year (HR = 29.54, 95% CI: 9.39-92.91, P < 0.001) and the development of worrisome features (HR = 9.17, 95% CI: 2.99-28.10, P = 0.001). Comparison of parametric survival models suggested that the risk of malignancy decreased after three years of surveillance and was lower than 0.2% after five years.

CONCLUSIONS

Pancreatic cysts <15  mm at the time of diagnosis have a very low risk of malignant transformation. Our findings indicate the risk decreases over time. Size increase of ≥2.5 mm/year is the strongest predictor of malignancy.

An elevated CA 19-9 is associated with invasive cancer and worse survival in IPMN

BACKGROUND

Current guidelines for IPMN include an elevated serum carbohydrate antigen (CA) 19-9 among the worrisome features. However, the correlation of CA 19-9 with histological malignant features and survival is unclear. Serum CEA is also currently used for preoperative management of IPMN, although its measurement is not evidence-based. Accordingly, we aimed to assess the role of these tumor markers as predictors of malignancy in IPMN.

METHODS

IPMN resected between 1998 and 2018 at Massachusetts General Hospital were analyzed. Clinical, pathological and survival data were collected and compared to preoperative levels of CA 19-9 and CEA. Receiver operating characteristic (ROC) and Cox regression analyses were performed considering cut-offs of 37 U/ml (CA 19-9) and 5 μg/l (CEA).

RESULTS

Analysis of 594 patients showed that preoperative CA 19-9 levels > 37 U/ml (n = 128) were associated with an increased likelihood of invasive carcinoma when compared to normal levels (45.3% vs. 18.0%, P < 0.001), while there was no difference with respect to high-grade dysplasia (32.9% vs 31.9%, P = 0.88). The proportion of concurrent pancreatic cancer was higher in patients with CA 19-9 > 37 U/ml (17.2% vs 4.9%, P < 0.001). An elevated CA 19-9 was also associated with worse overall and disease-free survival (HR = 1.943, P = 0.007 and HR = 2.484, P < 0.001 respectively). CEA levels did not correlate with malignancy.

CONCLUSION

In patients with IPMN, serum CA19-9 > 37 U/ml is associated with invasive IPMN and concurrent pancreatic cancer as well as worse survival, but not with high-grade dysplasia. Serum CEA appears to have minimal utility in the management of these patients.

Major Complications Independently Increase Long-Term Mortality After Pancreatoduodenectomy for Cancer

BACKGROUND

Postoperative major morbidity has been associated with worse survival gastrointestinal tumors. This association remains controversial in pancreatic cancer (PC). We analyzed whether major complications after surgical resection affect long-term survival.

METHODS

Records of all PC patients resected from 2007 to 2015 were reviewed. Major morbidity was defined as any grade-3 or higher 30-day complications, per the Clavien-Dindo Classification. Patients who died within 90 days after surgery were excluded from survival analysis.

RESULTS

Of 616 patients, 81.7% underwent pancreatoduodenectomy (PD) and 18.3% distal pancreatectomy (DP). Major complications occurred in 19.1% after PD and 15.9% after DP. In patients who survived > 90 days, the likelihood of receiving adjuvant treatment was 43.9% if major complications had occurred, vs. 68.5% if not (p < 0.001), and those who received it started the treatment median 10 days later compared with uncomplicated patients (median 60 days (50-72) vs. 50 days (41-61), p = 0.001). By univariate analysis, in addition to the conventional pathology-related prognostic determinants and the receipt of adjuvant treatment, major complications worsened long-term survival after PD (median OS 26 months vs. 15, p = 0.008). A difference was also seen after DP, but it did not reach statistical significance, likely related to the small sample size (median OS 33 months vs. 18, p = 0.189). At multivariate analysis for PD, major postoperative complications remained independently associated with worse survival [HR 1.37, 95%CI (1.01-1.86)].

CONCLUSIONS

Major surgical complications after pancreaticoduodenectomy are associated with worse long-term survival in pancreatic cancer. This effect is independent of the receipt of adjuvant treatment.

Surgical approach to pancreatic exocrine neoplasms

Pancreatic exocrine neoplasms represent a wide spectrum of pathophysiologic entities that challenge us as surgeons. The workup and management of these lesions continue to evolve as we better understand their complex nature. In this review, we will explore the contemporary clinical management of pancreatic adenocarcinoma, acinar cell carcinoma, and cystic neoplasms of the pancreas. The pathogenesis and epidemiology of these tumors will also be examined.

Degradation and inactivation of plasma tumor necrosis factor-alpha by pancreatic proteases in experimental acute pancreatitis

BACKGROUND

Release of TNFalpha is thought to play an important role in mediating systemic effects in acute pancreatitis (AP). We have been unable to find an elevation of plasma TNFalpha in AP and hypothesize that it is susceptible to catabolism by circulating pancreatic proteases.

METHODS

(1) AP was induced in Sprague-Dawley rats by cerulein hyperstimulation preceded by intraductal infusion of saline (mild) or glycodeoxycholic acid (severe). Healthy and sham-operated animals served as controls. Severity of pancreatitis was confirmed by histology. Plasma TNFalpha levels were measured at various time points after induction of AP with competitive ELISA. (2) Recombinant rat TNFalpha (rrTNFalpha) was incubated with trypsin, elastase, chymotrypsin and pepsin. Western Blot was performed to visualize TNF degradation. (3) RrTNFalpha was incubated in a concentration and time-dependant manner with proteases and TNF bioactivity was evaluated with a cytotoxicity assay.

RESULTS

(1) Plasma TNFalpha levels in severe pancreatitis were significantly lower than in sham-operated controls after 0.5 and 6 h. (2) Incubation with proteases showed degradation in the presence of trypsin, elastase and chymotrypsin and no effect of pepsin. (3) There was a concentration dependent inactivation of rrTNFalpha in the presence of pancreatic proteases and a complete time-dependent inactivation in the presence of trypsin.

CONCLUSION

Plasma TNFalpha does not rise in experimental AP, and levels are significantly lower in severe pancreatitis compared to sham-operated controls. Our study demonstrates degradation and inactivation of TNFalpha by pancreatic proteases, suggesting that it is unlikely it plays an important role in the development of distant organ failure.

Evaluation of morphology and microcirculation of the pancreas by ex vivo and in vivo reflectance confocal microscopy

BACKGROUND

Near-infrared reflectance confocal microscopy (CM) provides non-invasive real-time images of thin virtual horizontal tissue sections with high resolution and contrast.

AIM

Aim of the study was to characterize morphology, microcirculation and leukocyte-endothelial interaction (LEI) in normal pancreas by in vivo and ex vivo CM.

METHODS

For CM we used water immersion objective lenses of high numerical aperture and near-infrared wavelengths. Experimentally measured lateral optical resolution is 0.5-1 micron and the axial resolution is 3-5 microns. The maximum depth of resolution was 300-400 microns. For ex vivo imaging, freshly excised pancreatic tissue from rats was studied by reflectance CM and conventional histopathology. For in vivo CM, the pancreatic head was exteriorized on a specially constructed stage for imaging the microcirculation and LEI. Images were obtained in real time at rates of 30 frames/s and later analyzed off-line to evaluate LEI and functional capillary density (FCD).

RESULTS

CM allowed high resolution visualization of normal pancreas acinar cells, ducts, islets, capillaries and LEI in postcapillary venules. Histological images and optical sections from ex vivo CM can be correlated. Cellular morphology is better analyzed by conventional histology, but angioarchitecture and connective tissue structure are better evaluated by CM. FCD (265.7 +/- 16.6 cm-1) and LEI (rolling leukocytes 5.3 +/- 1.6/100 microns/sticking leukocytes 1.5 +/- 0.9/100 microns) were evaluated by in vivo CM in the normal pancreas.

CONCLUSIONS

CM findings in tissues ex vivo correlate with those of classical histology but add informative details of connective tissue structure and angioarchitecture. Potential future applications for in vivo CM include real-time analysis of microcirculation, leukocyte-endothelial interaction and angiostructure in inflammatory and malignant pancreatic diseases.

Cystic neoplasms of the pancreas

Cystic tumors of the pancreas have become increasingly prevalent. In large series, more than 90% of pancreatic cystic neoplasms are accounted for by mucinous cystadenomas and cystadenocarcinomas, serous cystadenomas, and intraductal papillary mucinous tumors. Differentiating cystic neoplasms from pseudocysts can almost always be accomplished by clinical and radiological means, but in doubtful cases, when observation is contemplated, or when it is important to determine preoperatively the type of cystic neoplasm, cyst fluid analysis is useful. This can be readily obtained by endoscopic ultrasound, and analysis of enzymes, viscosity, cytology and a variety of tumor markers allows for a better differential diagnosis.

Telomerase activity in periampullary tumors correlates with aggressive malignancy

OBJECTIVE

To determine the presence of telomerase activity in a variety of periampullary malignancies and pancreatic diseases and quantify its activity to establish any association with the stage or aggressiveness of malignancy.

SUMMARY BACKGROUND DATA

Progressive shortening of telomeres, repetitive DNA sequences at the ends of chromosomes, plays a role in cell senescence. Telomerase catalyzes conservation of telomeric repeats and may promote cell immortality and hence malignancy. It is absent in normal tissues but upregulated in more than 80% of cancers.

METHODS

Fresh specimens of 62 periampullary tumors were snap-frozen in liquid nitrogen and adjacent tissue was formalin-fixed for histopathology. The telomerase repeat amplification protocol (TRAP) was used to obtain telomerase DNA products. These were separated with gel electrophoresis, stained with SYBR green, and quantified by densitometry. Findings were confirmed with a fluorometric TRAP assay in which fluorescent primers specific for telomerase were selectively amplified in its presence.

RESULTS

Telomerase activity was upregulated in 26 of 33 periampullary malignancies (79%): 17 of 21 pancreatic adenocarcinomas (81%), 2 of 2 cholangiocarcinomas, 2 of 2 duodenal carcinomas, and 5 of 8 ampullary carcinomas (63%). Poorly differentiated periampullary tumors had significantly higher telomerase activity than well-differentiated tumors, and tumors larger than 2 cm had significantly higher telomerase activity than those 2 cm or smaller. Pancreatic ductal adenocarcinomas with lymph node metastases had significantly greater activity than node-negative cancers. Two of 11 intraductal papillary mucinous tumors were positive for telomerase activity, but only in foci of invasive carcinoma. Chronic pancreatitis (n = 7), serous cystadenomas (n = 5), benign mucinous cystic neoplasms (n = 4), neuroendocrine cancer (n = 1), and acinar cell carcinoma (n = 1) had no detectable telomerase activity.

CONCLUSION

Telomerase activity is common in periampullary carcinomas. The magnitude of activity correlates with aggressiveness in pancreatic adenocarcinoma and may prove useful as a molecular index for biologic staging.

Regional effects of nafamostat, a novel potent protease and complement inhibitor, on severe necrotizing pancreatitis

BACKGROUND

We evaluated the effect of the novel protease inhibitor nafamostat on rat necrotizing pancreatitis through different routes of administration.

METHODS

Three hours after the induction of severe pancreatitis, the rats received intravenous gabexate or intravenous or local mesenteric intra-arterial nafamostat. At 9 hours, ascites and bronchoalveolar lavage fluid were collected for the evaluation of capillary leakage (Evans blue extravasation). Pancreas and lung were excised for histologic features, myeloperoxidase, and trypsinogen activation peptide. Twenty-four hour survival was evaluated.

RESULTS

Only the intravenous infusion of nafamostat significantly reduced myeloperoxidase (11.7 +/- 2.3 vs 18.3 +/- 1.8 mU/mg; P <.05) and capillary leakage in lungs (Evans blue dye, 1.6 +/- 0.3 vs 2.6 +/- 0.3; P <.05). Only intra-arterial infusion of nafamostat significantly diminished capillary peritoneal leakage (Evans blue dye, 3.6 +/- 0.9 vs 9.4 +/- 0.4; P <.01). Typsinogen activation peptide levels were significantly reduced in all groups, but only intra-arterial infusion did so to baseline. Histologic inflammation in the pancreas was most significantly reduced after intra-arterial infusion (0.92 +/- 0.08 vs 2.91 +/- 0.06; P <.05). No form of protease inhibition reduced mortality rates.

CONCLUSIONS

The effects of protease inhibition depend on the route of administration. Nafamostat has maximal effects on the pancreas and peritoneal capillary leakage when delivered by way of local intra-arterial infusion, and shows a greater reduction of lung leukocyte infiltration and capillary leakage by the intravenous route. Nafamostat is more effective than gabexate.

Linkage of oxidative and nonoxidative ethanol metabolism in the pancreas and toxicity of nonoxidative ethanol metabolites for pancreatic acinar cells

BACKGROUND

Alcohol abuse is a major cause of pancreatic damage. Recent experimental evidence suggests that fatty acid ethyl esters (FAEE), nonoxidative ethanol metabolites, injure pancreatic acinar cells. Linkage between oxidative and nonoxidative metabolism of ethanol in the pancreas may contribute to increased FAEE levels.

METHODS

To study the association between oxidative and nonoxidative ethanol metabolism, FAEE concentration and FAEE synthase activity in rat pancreatic and liver homogenates incubated with ethanol were evaluated with and without inhibitors of oxidative ethanol metabolism. For toxicity studies, trypsinogen activation peptide synthesis as a measure of pancreatic cell injury was quantitated in unstimulated and cerulein-stimulated isolated pancreatic acinar cells incubated with ethanol or FAEE.

RESULTS

Inhibition of oxidative ethanol metabolism results in a 2- to 3-fold increase in nonoxidative ethanol metabolism to FAEE in pancreas and in liver. Both ethanol and FAEE induce increased intracellular trypsinogen activation by more than 50% in the presence of physiologic concentrations of cerulein in vitro.

CONCLUSIONS

These findings demonstrate that the inhibition of oxidative ethanol metabolism results in an increase in flux through the nonoxidative pathway and support the proposition that alcohol-induced pancreatic injury is mediated at least in part by FAEE, which are important products of pancreatic ethanol metabolism.

Biological implications of tumor cells in blood and bone marrow of pancreatic cancer patients

BACKGROUND

Patients with pancreatic cancer often have tumor recurrence despite curative resection. Cancer cells detected in blood or bone marrow at the time of diagnosis may relate to tumor stage and to prognosis. Recent research emphasis has centered on tumor cells in bone marrow aspirates, but whether these represent early micrometastases or blood-borne cells in transit is unknown.

PATIENTS AND METHODS

We developed a specific immunocytochemical assay that evaluated more than 5.3 x 10(6) extracted mononuclear cells per sample of blood and bone marrow and that could identify a single tumor cell in that population. The assay was applied to samples of blood and bone marrow from 105 patients with pancreatic cancer and 66 controls. The prevalence of isolated tumor cells was compared with Union Internationale Contre le Cancer (UICC) stage. A multivariate Cox regression analysis for survival was performed.

RESULTS

Pancreatic cancer cells were detected in 26% of blood samples and in 24% of bone marrow specimens. Specificity for cancer was 96%. The prevalence of isolated tumor cells in patients with proven resectable cancer was 9% in blood and 13% in bone marrow. The prevalence increased with UICC tumor stage in blood (P =.04) but not in bone marrow (P =.52) and correlated in blood with resectability (P =.02), progression of disease (P=.08), and peritoneal dissemination (P =.003). While survival correlated significantly with tumor stage (P <.001) and isolated tumor cells in blood correlated with tumor stage, the finding of cancer cells in blood or bone marrow, or both, was not independently associated with survival in patients with pancreatic cancer.

CONCLUSIONS

Isolated tumor cells in blood but not bone marrow reflect the stage of growth and spread of pancreatic cancer, particularly in the peritoneal cavity. The findings are consistent with cells in bone marrow aspirates being in transit, not implanted. These disseminated cancer cells may be the consequence, rather than the cause, of progression.

Promoting effect of a high-fat/high-protein diet in DMBA-induced ductal pancreatic cancer in rats

OBJECTIVE

To investigate whether a high-fat/high-protein diet (HFPD) acts as a promoter of the natural course of cancer growth in the 7,12-dimethylbenzanthracene (DMBA)-induced ductal pancreatic cancer model in rats.

SUMMARY BACKGROUND DATA

DMBA implantation to the rat pancreas induces ductal adenocarcinoma. Information regarding the effects of diet and the presence of K-ras mutation in this model is not available.

METHODS

Rats were randomly assigned to regular rat chow or a diet with a 30% content in fat and protein (HFPD). The presentation of cancer, the histologic spectrum of neoplasia at 1 and 9 months, and the prevalence of cancer in relation to diet were assessed. Histologic specimens comprising normal ducts, hyperplasia, dysplasia/carcinoma in situ, or carcinoma were designated by a pathologist and microdissected. Genomic DNA was extracted, and K-ras and H-ras gene mutations were determined by a mutant-enriched polymerase chain reaction assay and direct sequencing.

RESULTS

Rats fed HFPD increased their weight significantly compared with controls. DMBA induced characteristic stages of neoplasia at the implant site but not elsewhere. Macroscopic cancers of the pancreatic head presented regularly with common bile duct and gastric outlet obstruction. The prevalence of K-ras mutations was proportional to the degree of epithelial abnormality. K-ras mutations were significantly more frequent in cancer than in normal and hyperplastic ducts. H-ras mutations were not found. At 1 month in the HFPD-fed rats, the prevalence of cancer (16%) and dysplasia (16%) was not significantly different from the prevalence of cancer (29%) and dysplasia (8%) in the chow-fed rats. At 9 months the prevalence of cancer in the HFPD-fed rats increased to 29%, whereas that in the chow-fed rats decreased to 17%. The combined prevalence of cancer and dysplasia at 9 months in the HFPD-fed rats (34%) significantly exceeded that in the chow-fed rats.

CONCLUSIONS

DMBA induces characteristic stages of neoplasia in the evolution of ductal pancreatic cancer in rats. K-ras mutations occur progressively in the ladder of oncogenesis, as in human pancreatic neoplasms. The addition of a diet with a high fat and protein content acts as a promoter of carcinogenesis, possibly by interfering with repair mechanisms and natural regression of early lesions.

Ten-year experience with 733 pancreatic resections: changing indications, older patients, and decreasing length of hospitalization

HYPOTHESIS

Experience with pancreatic resection for the last 10 years has resulted in new trends in patient characteristics and, for pancreaticoduodenectomy (PD), a decrease in the length of stay (LOS). This decrease is due in part to the implementation of case management and clinical pathways.

DESIGN

Retrospective case series of patients undergoing pancreatic resection.

SETTING

A university-affiliated, tertiary care referral center.

PATIENTS

The study comprised 733 consecutive patients undergoing pancreatic resection for benign or malignant disease at the Massachusetts General Hospital in Boston from April 1990 to March 2000.

INTERVENTIONS

Of the 733 pancreatic resections, 489 were PD; 190, distal pancreatectomy; 40, total pancreatectomy; and 14, middle-segment pancreatectomy.

MAIN OUTCOME MEASURES

Length of stay; occurrence of delayed gastric emptying, pancreatic fistula, reoperation, readmission, or other complications; mortality; and comparison of patients in 3 periods according to the implementation of case management (July 1995) and clinical pathways (September 1998).

RESULTS

For PD, patients in group 1 (April 1990 to June 1995) were significantly younger (mean +/- SD, 57 +/- 15 years) than those in group 2 (July 1995 to August 1998; mean +/- SD, 62 +/- 13 years) and group 3 (September 1998 to October 2000; mean +/- SD, 65 +/- 13 years)(P <.01). Over time, the proportion of PD for cystic tumors increased from 9.9% to 20% (P =.01), and the proportion of PD for chronic pancreatitis decreased from 23% to 10% (P <.01). Use of pylorus-preserving PD decreased from 45% to 0% (P <.001). Delayed gastric emptying decreased from 17% to 6.1% (P <.01). Pancreatic fistula, reoperation, and mortality were unchanged. Length of stay for PD decreased from 16.1 +/- 0.6 to 9.5 +/- 0.4 days (mean +/- SE) (P <.001). Multivariate analysis showed that period, case volume, pylorus-preserving PD, and presence of complications are all independent predictors of LOS (P <.05 for all). For distal pancreatectomy, patients in groups 2 and 3 were older than those in group 1 (mean +/- SD, 57 +/-14 vs 52 +/- 17 years) (P <.05). Resections for cystic tumors increased from 26% to 52% (P <.05), and resections for chronic pancreatitis decreased from 32% to 14% (P =.06). Median LOS decreased from 9 days to 6. For total pancreatectomy, resections for cystic tumors increased from 18% to 43%. Median LOS decreased from 14.5 days to 11. For all resections, case volume increased from 4 resections per month in 1990 to 5.8 in 1995 and 12 in 2000 (r = 0.83; P <.001).

CONCLUSIONS

Older patients are increasingly being selected for pancreatic resection. This reflects an increasing frequency of operations performed for cystic tumors and fewer for chronic pancreatitis. With the exception of delayed gastric emptying, complications and mortality have remained the same or decreased slightly during the past 10 years. However, there has been a significant decrease in LOS; this is the result of implementation of case management and clinical pathways, increasing case volume, decreasing incidence of delayed gastric emptying, and decreasing use of pylorus-preserving PD.

Expression of the adhesion molecules Mac-1 and L-selectin on neutrophils in acute pancreatitis is protease- and complement-dependent

OBJECTIVE

To examine the effect of pancreatic proteases on the expression of the adhesion molecules Mac-1 and l-selectin on neutrophils, and the role of complement activation in this process.

SUMMARY BACKGROUND DATA

Sequestration of neutrophils in the pancreatic and pulmonary microvasculature characterizes acute pancreatitis.

METHODS

Serum was collected from inbred rats after induction of necrotizing pancreatitis; trypsinogen activation peptide was measured to quantify trypsin activation. Normal rat serum was also collected and subjected to limited trypsin digestion with and without the addition of complement inhibitor. Both groups of sera were incubated in vitro with healthy leukocytes. Expression of Mac-1 and L-selectin on neutrophils was measured quantitatively by flow cytometry. To assess the consequences of these events in vivo, trypsinated serum with or without complement inhibition or control serum was infused intravenous into rats. Soybean trypsin inhibitor was added to serum before injections to block residual trypsin activity. Pancreatic and pulmonary injury was quantitated by histology, measurement of edema, and myeloperoxidase activity.

RESULTS

Mac-1 expression on neutrophils incubated with pancreatitis serum was increased compared with controls, whereas L-selectin was decreased. Neutrophils incubated with trypsinated serum also showed upregulation of Mac-1 and downregulation of L-selectin, particularly with trypsin at 10(-4) mol/L. Addition of soluble complement receptor 1 abrogated both Mac-1 upregulation and L-selectin downregulation. Lungs of animals injected with trypsinated serum showed increased edema and myeloperoxidase activity, which were reduced by soluble complement receptor 1.

CONCLUSIONS

Trypsin-generated complement activation participates in the upregulation of Mac-1 and shedding of L-selectin on neutrophils in acute pancreatitis. Protease or complement inhibition may be effective in preventing leukocyte migration and subsequent local and remote organ injury.

Overexpression of cyclin D1 occurs frequently in human pancreatic endocrine tumors

The molecular pathogenesis of human pancreatic endocrine tumors (PETs) is poorly understood. Three independent animal models have pointed to the pivotal role of the G1/S cell cycle transition in pancreatic endocrine cell proliferation. We thus hypothesized that the cell cycle regulator cyclin D1 may contribute to the pathogenesis of human PETs. Overexpression of cyclin D1 was identified in 43% of cases, and no correlation was observed with clinical phenotype. The novel observation of frequent overexpression of cyclin D1 suggests that this established oncogene may be implicated in the pathogenesis of human PETs. The absence of detectable alterations in cyclin D1 genomic structure suggests that the mechanism for its oncogenic activation in PETs may be transcriptional or posttranscriptional.

Laparoscopy and peritoneal cytology in the staging of pancreatic cancer

Staging laparoscopy in patients with pancreatic cancer allows identification of metastatic disease which is beyond the resolution of computed tomography. Laparoscopic ultrasound, dissection, and/or peritoneal cytology may be used to enhance the sensitivity of the staging procedure. Our experience at Massachusetts General Hospital with staging laparoscopy and peritoneal cytology over the past 8 years (N = 239) reveals that approximately 30% of patients without metastases by computed tomography harbor occult metastatic disease at laparoscopy. Additionally, published series demonstrate accurate determination of resectability in greater than 75% of patients after staging laparoscopy. Staging laparoscopy in patients with pancreatic cancer allows optimization of resources and avoidance of unnecessary surgery.

Laparoscopy and peritoneal cytology in the staging of pancreatic cancer

Staging laparoscopy in patients with pancreatic cancer allows identification of metastatic disease which is beyond the resolution of computed tomography. Laparoscopic ultrasound, dissection, and/or peritoneal cytology may be used to enhance the sensitivity of the staging procedure. Our experience at Massachusetts General Hospital with staging laparoscopy and peritoneal cytology over the past 8 years (N = 239) reveals that approximately 30% of patients without metastases by computed tomography harbor occult metastatic disease at laparoscopy. Additionally, published series demonstrate accurate determination of resectability in greater than 75% of patients after staging laparoscopy. Staging laparoscopy in patients with pancreatic cancer allows optimization of resources and avoidance of unnecessary surgery.

Effect of matrix metalloproteinase inhibition on pancreatic cancer invasion and metastasis: an additive strategy for cancer control

OBJECTIVE

To investigate the effect of a matrix metalloproteinase (MMP) inhibitor, BB-94, on the viability, invasion, and metastases of pancreatic cancer.

SUMMARY BACKGROUND DATA

Inhibitors of MMPs, enzymes that degrade extracellular matrix, have been tested as single chemotherapeutic agents for pancreatic cancer.

METHODS

Capan1 and AsPC1 cell lines were studied. BB-94 cytotoxicity was evaluated by cell proliferation assays. Production of MMP2 and MMP9 in conditioned media was demonstrated by gelatin zymography. The in vitro effect of BB-94 on cell invasion was assayed using invasion chambers. Hepatic metastases from pancreatic cancer were induced by intrasplenic injections of Capan1 or AsPC1 cells in nude mice. The in vivo effect of BB-94 on liver metastases was evaluated by comparing animals receiving BB-94 treatment with controls receiving vehicle alone. Variables measured included death rate and tumor burden (liver-to-body weight ratio).

RESULTS

BB-94 was not cytotoxic between 3 and 3,000 ng/mL. Zymography demonstrated production of MMP2 and MMP9 by both cell lines, with complete inhibition of these enzymes by BB-94 at 48 ng/mL. Invasion chamber assays showed that BB-94 (48-400 ng/mL) impeded cell invasion in vitro compared with untreated controls. In vivo, BB-94 prevented death or reduced the death rate from hepatic metastases in animals injected with Capan1 or AsPC1 cells. BB-94 treatment resulted in significant reductions in hepatic tumor burden compared with untreated controls.

CONCLUSIONS

Inhibition of MMP reduces both growth of pancreatic cancer metastases and the death rate. These actions do not reflect cytotoxicity but rather result from impaired cancer cell attachment, migration, and organ invasion. MMP inhibitors may provide an additive effect to cytotoxic agents in multidimensional treatment regimens for pancreatic cancer.

Cystic lesions in the pancreas: when to watch, when to resect

The diagnosis of cystic lesions in the pancreas is becoming more common, largely due to the increases in diagnostic imaging done for other reasons. This review considers pseudocysts, mucinous cystic neoplasms, intraductal papillary mucinous tumors, and serous cystadenomas in some detail. The emphasis is on the fact that, through a careful history, physical examination, radiologic studies, and, often, cyst fluid analysis, a diagnosis can be reached expeditiously. This pursuit is important because two thirds of pancreatic cystic neoplasms are malignant or premalignant and should be resected, whereas pseudocysts and serous cystadenomas are benign, and, depending on the case, may be treated through observation, resection, or, for pseudocysts, by internal drainage.

Impact of laparoscopic staging in the treatment of pancreatic cancer

HYPOTHESIS

Staging laparoscopy in patients with pancreatic cancer identifies unsuspected metastases, allows treatment selection, and helps predict survival.

DESIGN

Inception cohort.

SETTING

Tertiary referral center.

PATIENTS

A total of 125 consecutive patients with radiographic stage II to III pancreatic ductal adenocarcinoma who underwent staging laparoscopy with peritoneal cytologic examination between July 1994 and November 1998. Seventy-eight proximal tumors and 47 distal tumors were localized.

INTERVENTIONS

Based on the findings of spiral computed tomography (CT) and laparoscopy, patients were stratified into 3 groups. Group 1 patients had unsuspected metastases found at laparoscopy and were palliatedwithout further operation. Group 2 patients had no demonstrable metastases, but CT indicated unresectability due to vessel invasion. This group underwent external beam radiation with fluorouracil chemotherapy followed in selected cases by intraoperative radiation. Patients in group 3 had no metastases or definitive vessel invasion and were resection candidates.

MAIN OUTCOME MEASURE

Survival.

RESULTS

Staging laparoscopy revealed unsuspected metastases in 39 patients (31.2%), with 9 having positive cytologic test results as the only evidence of metastatic disease (group 1). Fifty-five patients (44.0%) had localized but unresectable carcinoma (group 2), of whom 2 (3.6%) did not tolerate treatment, 20 (36.4%) developed metastatic disease during treatment, and 21 (38.2%) received intraoperative radiation. Of 31 patients with potentially resectable tumors (group 3), resection for cure was performed in 23 (resectability rate, 74.2%). Median survival was 7.5 months for patients with metastatic disease, 10.5 months for those receiving chemoradiation, and 14.5 months for those who underwent tumor resection (P = .01 for group 2 vs. group 1; P<.001 for group 3 vs group 1).

CONCLUSIONS

Staging laparoscopy, combined with spiral CT, allowed stratification of patients into 3 treatment groups that correlated with treatment opportunity and subsequent survival. Among the 125 patients, laparoscopy obviated 39 unnecessary operations and irradiation in patients with metastatic disease not detectable by CT. Laparoscopic staging can help focus aggressive treatment on patients with pancreatic cancer who might benefit.

[Parenchymal necrosis: infection and other indications for debridement and drainage]

In the present review we describe our experience with debridement in necrotizing pancreatitis, with particular emphasis on the indications for surgery and the outcome in patients with infected and sterile necrosis. Within 7 years 64 patients with necrotizing pancreatitis underwent surgery with a median preoperative APACHE II score of 9. The indications for surgery were either proven infection or persistence of symptoms. Thirty-six patients were found to have infected necrosis, while 28 patients had sterile necrosis. There was no significant difference between the two groups regarding pre- and postoperative parameters. The surgical technique involved a blunt necrosectomy followed by closed packing with Penrose drains. This technique produced the lowest reported mortality of 6.2% with a reoperation rate of only 17%, demonstrating that even with sterile necrosis surgical management can be carried out safely.

Comparison of in-phase and out-of-phase gradient recalled echo T1-weighted pulse sequence for MR imaging of malignant liver masses following administration of paramagnetic gadolinium-chelate

BACKGROUND

The purpose of this study was to compare the performance of in-phase and out-of-phase gradient recalled echo (GRE) pulse sequences on paramagnetic contrast-enhanced magnetic resonance (MR) imaging of malignant liver lesions.

METHODS

Fifty patients (27 women, 23 men; mean age = 50 +/- 27 years) with known or suspected focal liver lesions, nine of whom had a fatty liver, were examined at 1.5 T before and 60 min after injection of gadobenate dimeglumine at a dose of 0.05 or 0.1 mmol/kg using two GRE techniques: echo time of 2.3 ms (out-of-phase) or 4.6 ms (in-phase). Liver signal-to-noise ratio (SNR) and lesion-liver contrast-to-noise ratio (CNR) were calculated.

RESULTS

In patients with a nonfatty liver, liver SNR increased from 26 +/- 9 to 41 +/- 17 on in-phase images and from 28 +/- 8 to 45 +/- 14 on out-of-phase images. In patients with a fatty liver, in-phase images provided significantly higher (p < 0.01) liver SNR than did out-of-phase images predose (34 +/- 8 on in-phase vs. 21 +/- 8 on out-of-phase) and postdose (44 +/- 13 on in-phase vs. 33 +/- 14 on out-of-phase). In patients with a nonfatty liver, lesion-liver CNR was similar on in-phase and out-of-phase images, predose and postdose. In patients with fatty liver, lesion-liver CNR was significantly (p < 0.01) lower on out-of-phase images on predose and postdose images.

CONCLUSION

In-phase GRE imaging is recommended for imaging focal liver lesions on paramagnetic contrast-enhanced MR imaging in patients with fatty infiltration of the liver.

Outcome of pancreaticoduodenectomy with pylorus preservation or with antrectomy in the treatment of chronic pancreatitis

OBJECTIVE

To compare the short- and long-term results of pancreaticoduodenectomy with pylorus preservation (PPPD) or with antrectomy (Whipple procedure) in the treatment of selected patients with chronic pancreatitis.

BACKGROUND

PPPD may be preferred over Whipple because of its purported nutritional advantages and the reduced likelihood of postgastrectomy syndromes.

METHODS

A retrospective review was performed of 72 consecutive patients undergoing pancreaticoduodenectomy for chronic pancreatitis between 1991 and 1997.

RESULTS

PPPD was performed in 39 patients and Whipple in 33. The two patient populations had similar characteristics. Short-term complications included (PPPD vs. Whipple): pancreatic or biliary fistulas (5.1% vs. 15%), delayed gastric emptying (33% vs. 12%), cholangitis (2.6% vs. 6.1%), and death (0 vs. 3%). Delayed gastric emptying was not associated with other complications and resulted in longer hospital stays for PPPD than for Whipple patients (15 vs. 12 days). The duration of follow-up averaged 41 +/- 24 months. Long-term weight status was similar, with body-mass indices of 22.1 and 22.9 after PPPD and Whipple, respectively. Postoperative enzyme supplementation (63% vs. 77%) and new-onset diabetes (10% vs. 12%) did not differ significantly between the PPPD and Whipple groups. Dumping, bile gastritis, or peptic ulcer disease occurred in three patients after PPPD and in three after Whipple. Complete or partial pain relief was attained in 60% and 70% of patients after PPPD and Whipple, respectively. Multivariate analysis of preoperative variables revealed that site-specific pathology in the head of the pancreas was the only independent factor associated with successful pain relief after pancreatic resection.

CONCLUSION

PPPD results in higher frequencies of postoperative delayed gastric emptying compared with the Whipple procedure. Both operations achieve comparable long-term nutritional results, cause new insulin dependence in surprisingly few patients, and provide equivalent pain relief to 65% of selected patients. Patients with disproportionate pathology in the head of the pancreas have a higher likelihood of successful pain relief.

Adenocarcinoma of the head of the pancreas: determination of surgical unresectability with thin-section pancreatic-phase helical CT

OBJECTIVE

This study was conducted to evaluate newly introduced criteria for unresectability of pancreatic cancer with thin-section pancreatic-phase helical CT.

MATERIALS AND METHODS

Twenty-five patients with adenocarcinoma in the head of the pancreas underwent thin-section pancreatic-phase helical CT. The major peripancreatic vessels were categorized on a scale of 1-4, according to the degree of circumferential involvement by tumor. The maximum diameters of the small peripancreatic veins--gastrocolic trunk, anterosuperior pancreaticoduodenal vein, and posterosuperior pancreaticoduodenal vein--were recorded. Findings on CT were compared with the results of surgery in each patient.

RESULTS

Sixteen patients had surgically resectable tumors, and nine patients had surgically unresectable tumors. CT and surgical correlation was available for 98 major peripancreatic vessels; 85 were resectable and 13 were unresectable. Of category 1 vessels, 72 (97%) of 74 were resectable at surgery. Of category 2 vessels, 12 (71%) of 17 were resectable. One (50%) of two category 3 vessels and none (0%) of five category 4 vessels were resectable at surgery. CT showed a dilated gastrocolic trunk in two patients; one of these patients had a surgically resectable tumor, but the other patient had a surgically unresectable tumor.

CONCLUSION

In patients with adenocarcinoma in the head of the pancreas, the degree of circumferential vessel involvement by tumor as shown by CT is useful in predicting which patients will have surgically unresectable tumors. A dilated gastrocolic trunk should not be used as an independent sign of surgical unresectability.

Trypsin and activation of circulating trypsinogen contribute to pancreatitis-associated lung injury

Pancreatic proteases are secreted in acute pancreatitis, but their contribution to associated lung injury is unclear. Applying models of mild edematous (intravenous caerulein) and severe necrotizing (intraductal glycodeoxycholic acid) pancreatitis in rats, we showed that both trypsinogen and trypsin concentrations in peripheral blood, as well as lung injury, correlate with the severity of the disease. To isolate the potential contribution of proteases to lung injury, trypsin or trypsinogen was injected into healthy rats or trypsinogen secreted in caerulein pancreatitis was activated by intravenous enterokinase. Pulmonary injury induced by protease infusions was dose dependent and was ameliorated by neutrophil depletion. Trypsinogen activation worsened lung injury in mild pancreatitis. In vitro incubation of leukocytes with trypsinogen showed that stimulated leukocytes can convert trypsinogen to trypsin. In conclusion, this study demonstrates that the occurrence and severity of pancreatitis-associated lung injury (PALI) corresponds to the levels of circulating trypsinogen and its activation to trypsin. Neutrophils are involved in both protease activation and development of pulmonary injury.

Sequential accumulation of K-ras mutations and p53 overexpression in the progression of pancreatic mucinous cystic neoplasms to malignancy

OBJECTIVE

Pancreatic mucinous cystic neoplasms (MCNs) provide a spectrum of neoplastic changes ranging from benign to malignant. The authors have correlated K-ras mutations and p53 overexpression with the evolution of these tumors.

METHODS

Areas of mild, moderate, or severe dysplasia were microdissected from paraffin-embedded tissue sections of 28 different MCNs (10 benign, 9 borderline, 9 malignant). Nonneoplastic pancreatic ducts were also microdissected from tissues adjacent to the tumors. Ten serous cystadenomas served as negative controls. K-ras codon 12 mutations were identified by a mutant-enriched nested polymerase chain reaction-restriction fragment length polymorphism assay and confirmed by sequencing. p53 overexpression was demonstrated by immunohistochemistry.

RESULTS

K-ras mutations were detected in 20% of benign, 33% of borderline, and 89% of malignant MCNs. Histologically, mutations were found in 26% (7/27) of MCN epithelia with mild dysplasia, 38% (5/13) of MCN epithelia with moderate dysplasia, and 89% (8/9) of MCN epithelia with severe dysplasia or carcinoma. Ten percent (4/39) of nonneoplastic pancreatic ducts at the margins of MCN harbored mutations, all associated with borderline or malignant tumors. Overexpression of p53 occurred in none of the benign or borderline MCNs but in 44% (4/9) of the malignant tumors (p = 0.006 benign/borderline vs. malignant). p53 immunoreactivity was concentrated in areas of severe dysplasia/carcinoma or invasion, where K-ras mutation had been detected.

CONCLUSION

These findings demonstrate a sequential accumulation of genetic changes in the carcinogenesis of MCN. K-ras mutations appear early and increase in proportion with increasing dysplasia. Overexpression of p53 is a late finding observed only in carcinomas, and in combination with mutated K-ras genes. The presence of K-ras mutations in nonneoplastic ducts supports formal pancreatic resection over enucleation for treatment. Mucinous cystic neoplasms may be a useful model to study the evolution of pancreatic ductal adenocarcinomas, in which precursor lesions remain unknown.

Cystic pancreatic neoplasms

Cystic pancreatic neoplasms comprise a heterogeneous group of pathologic entities. Mucinous cystic tumors and serous cystadenomas account for more than 75% of reported cases. While serous cystadenomas are almost uniformly benign, mucinous cystic tumors all have malignant potential and must be treated as such. While both clinical and biochemical features can distinguish among the various cystic pancreatic lesions, surgical resection is often required for both definitive diagnosis and treatment. When surgery is performed, benign lesions should be treated with pancreatic parenchymal sparing procedures if anatomy permits. Standard surgical oncologic principles should be employed when treating indeterminate or malignant lesions.

Relationship between hospital volume and late survival after pancreaticoduodenectomy

BACKGROUND

Several studies have reported lower perioperative mortality rates with pancreaticoduodenectomy at high-volume hospitals than at low-volume hospitals. We sought to determine whether volume is also related to survival after hospital discharge.

METHODS

Using information from the Medicare claims database, we performed a retrospective cohort study of all 7229 patients over age 65 undergoing pancreaticoduodenectomy in the United States between 1992 and 1995. We divided the study population into approximate quartiles according to their hospital's average annual volume of pancreaticoduodenectomies in Medicare patients: very low (< 1/y), low (1-2/y, medium (2-5/y), and high (5+/y). To adjust for potentially confounding variables, we used a Cox proportional hazards model to examine relationships between hospital volume and mortality, our primary outcome measure.

RESULTS

Overall, 3-year survival was higher at high-volume centers (37%) than at medium- (29%), low- (26%), and very low volume hospitals (25%) (log-rank P < .0001). After excluding perioperative deaths and adjusting for case-mix, patients undergoing surgery at high-volume hospitals remained less likely to experience late mortality than patients at very low volume centers (adjusted hazard ratio 0.69, 95% CI 0.62-0.76). Relationships between hospital volume and survival after discharge were not restricted to patients with cancer diagnoses; patients with benign disease had similar improvements in late survival after surgery at high-volume centers.

CONCLUSIONS

Hospital volume strongly influences both perioperative risk and long-term survival after pancreaticoduodenectomy. Our data suggest that both patient selection and differences in quality of care may underlie better outcomes at high-volume referral centers.

Interstitial trypsinogen release and its relevance to the transformation of mild into necrotizing pancreatitis in rats

BACKGROUND & AIMS

Intracellular activation of trypsinogen is currently believed to initiate pancreatitis. Factors responsible for the progression of mild to necrotizing pancreatitis are poorly understood. This study evaluated the significance of interstitial protease release and activation in this process.

METHODS

In rats with cerulein-induced pancreatitis, concentrations of trypsinogen and its activation peptide TAP were measured in lymph and blood, and pancreatic injury was determined. Activation of extracellular trypsinogen was induced by intravenous infusion of enterokinase, which does not enter the acinar cell. Gabexate mesilate (acinar cell permeable) or soybean trypsin inhibitor (acinar cell nonpermeable) was administered to distinguish the effects of intracellular or extracellular protease activation.

RESULTS

In cerulein pancreatitis, trypsinogen levels increased prominently and were highest in lymph and portal vein blood, whereas TAP increments were modest. Combined cerulein/enterokinase infusions resulted in marked TAP increases in lymph and blood and in severe necrohemorrhagic pancreatitis. Gabexate mesilate as well as soybean trypsin inhibitor significantly decreased TAP levels in both lymph and blood and reduced pancreatic injury, with no significant differences between groups.

CONCLUSIONS

In secretagogue-induced pancreatitis, large amounts of trypsinogen are present in the interstitium and drain via the portal and lymphatic circulation. Activation of this extracellular trypsinogen induces hemorrhagic necrosis in a setting of mild edematous pancreatitis. This phenomenon may be the central event in the progression to fulminant necrotizing pancreatitis.

Relationship between hospital volume and late survival after pancreaticoduodenectomy

BACKGROUND

Several studies have reported lower perioperative mortality rates with pancreaticoduodenectomy at high-volume hospitals than at low-volume hospitals. We sought to determine whether volume is also related to survival after hospital discharge.

METHODS

Using information from the Medicare claims database, we performed a retrospective cohort study of all 7229 patients over age 65 undergoing pancreaticoduodenectomy in the United States between 1992 and 1995. We divided the study population into approximate quartiles according to their hospital's average annual volume of pancreaticoduodenectomies in Medicare patients: very low (< 1/y), low (1-2/y, medium (2-5/y), and high (5+/y). To adjust for potentially confounding variables, we used a Cox proportional hazards model to examine relationships between hospital volume and mortality, our primary outcome measure.

RESULTS

Overall, 3-year survival was higher at high-volume centers (37%) than at medium- (29%), low- (26%), and very low volume hospitals (25%) (log-rank P < .0001). After excluding perioperative deaths and adjusting for case-mix, patients undergoing surgery at high-volume hospitals remained less likely to experience late mortality than patients at very low volume centers (adjusted hazard ratio 0.69, 95% CI 0.62-0.76). Relationships between hospital volume and survival after discharge were not restricted to patients with cancer diagnoses; patients with benign disease had similar improvements in late survival after surgery at high-volume centers.

CONCLUSIONS

Hospital volume strongly influences both perioperative risk and long-term survival after pancreaticoduodenectomy. Our data suggest that both patient selection and differences in quality of care may underlie better outcomes at high-volume referral centers.

Chemotactic peptide uptake in acute pancreatitis: correlation with tissue accumulation of leukocytes

Chemotactic peptides bind specifically to receptors on leukocyte membranes. This property makes them prospective vehicles to evaluate inflammation and infection. We used two well-established models of acute pancreatitis to quantitate the binding of the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine-lysine (fMLFK) to leukocytes and its correlation to degree of organ inflammation. Uptake of the (99m)Tc-labeled nicotinyl hydrazine-derivatized chemotactic peptide analog fMLFK-HYNIC was measured in blood, pancreas, lung, and muscle specimens in rats with edematous or necrotizing pancreatitis and was compared with neutrophil sequestration assessed by myeloperoxidase activity and histology. Chemotactic peptide uptake in the pancreas was increased in mild and severe pancreatitis compared with controls, with higher levels in severe than in mild disease, and correlated with tissue myeloperoxidase activity (r = 0.7395, P < 0.001). Increased pulmonary uptake only in severe pancreatitis reflected pancreatitis-induced neutrophil sequestration in the lungs. Muscle uptake was unchanged compared with controls. Edema formation did not affect chemotactic peptide uptake. The data suggest that uptake of chemotactic peptides can contribute to quantitative assessment of neutrophils in localized inflammatory processes and is independent of associated edema formation or microcirculatory compromise.

Specific therapy for local and systemic complications of acute pancreatitis with monoclonal antibodies against ICAM-1

OBJECTIVE

To analyze the time points and levels of the expression of adhesion molecules in the pancreas and lung in pancreatitis of different severities, and to assess whether treatment with a monoclonal antibody against intercellular adhesion molecule-1 (ICAM-1) can reduce local and systemic complications.

BACKGROUND

The outcome of severe acute pancreatitis relates to its pulmonary and septic complications. Leukocyte adhesion and infiltration, both mediated by ICAM-1, are central events in the pathogenesis of necrotizing pancreatitis.

METHODS

Expression of ICAM-1 at different time points was assessed by immunohistochemistry and Western blot analysis in pancreas and lungs from rats with mild edematous or severe necrotizing pancreatitis. ICAM-1 expression was correlated with leukocyte infiltration and histologic changes. The possible therapeutic effect of monoclonal antibodies against ICAM-1 was assessed by measuring pancreatic and lung injury.

RESULTS

In edematous pancreatitis, increased ICAM-1 expression in pancreas was evident by 6 hours but did not occur in lung. In contrast, ICAM-1 was upregulated at 3 hours in the pancreas and at 12 hours in lung in necrotizing pancreatitis. Increased expression of ICAM-1 preceded leukocyte infiltration. Treatment of severe necrotizing pancreatitis with monoclonal antibodies against ICAM-1 decreased both local pancreatic injury and systemic lung injury compared with untreated controls.

CONCLUSIONS

Upregulation of ICAM-1 and subsequent leukocyte infiltration appear to be significant mediators of pancreatic and pulmonary injury in pancreatitis, and both the onset and extent correlate with severity. The time course should permit effective prevention of tissue damage by treatment with ICAM-1 antibodies.

Immunohistochemical characterization of pancreatic tumors induced by dimethylbenzanthracene in rats

Dimethylbenzanthracene (DMBA) induces pancreatic adenocarcinomas in rats 9 months after carcinogen exposure, with precursor lesions (tubular complexes) developing 1 month after initiation of treatment. Because previous studies have suggested an acinar cell of origin for these tumors, we investigated the expression pattern of ductal, acinar, and islet cell markers in these cancers to gain insight into their phenotype and cell of origin. Pancreatic neoplasms were induced in rats by implantation of DMBA into the head of the pancreas. Lesions studied included 10 early tubular complexes (DMBA for 2 weeks), 8 tubular complexes (DMBA for 1 month), and 10 adenocarcinomas (DMBA for 9 months). Normal rat pancreas served as a control. For comparison, 5 human ductal adenocarcinomas were also evaluated. Immunohistochemistry with ductal (keratin, cytokeratin 19, cytokeratin 20), acinar (chymotrypsin), and islet (chromogranin A) cell markers was performed to analyze the tissues. Rat tubular complexes and adenocarcinomas revealed strong expression of keratin, cytokeratin 19, and cytokeratin 20 in the cytoplasm of all neoplastic cells, absence of chymotrypsin, and rare immunoreactivity to chromogranin A. Human adenocarcinomas showed strong expression of keratin and cytokeratin 19 in all neoplastic cells, expression of cytokeratin 20 in 5-20% of cells, and absence of chymotrypsin and chromogranin A. Pancreatic adenocarcinomas induced by DMBA in rats express markers consistent with a ductal phenotype, as observed in human tumors. Ductal marker expression in early tumor stages suggests a ductal cell of origin.

Effect of hospital volume on in-hospital mortality with pancreaticoduodenectomy

BACKGROUND

Reports of better results at national referral centers than at low-volume community hospitals have prompted calls for regionalizing pancreaticoduodenectomy (the Whipple procedure). We examined the relationship between hospital volume and mortality with this procedure across all US hospitals.

METHODS

Using information from the Medicare claims database, we performed a national cohort study of 7229 Medicare patients more than 65 years old undergoing pancreaticoduodenectomy between 1992 and 1995. We divided the study population into approximate quartiles according to the hospital's average annual volume of pancreaticoduodenectomies in Medicare patients: very low (< 1/y), low (1-2/y), medium (2-5/y), and high (5+/y). Using multivariate logistic regression to account for potentially confounding patient characteristics, we examined the association between institutional volume and in-hospital mortality, our primary outcome measure.

RESULTS

More than 50% of Medicare patients a undergoing pancreaticoduodenectomy received care at hospitals performing fewer than 2 such procedures per year. In-hospital mortality rates at these low- and very-low-volume hospitals were 3- to 4-fold higher than at high-volume hospitals (12% and 16%, respectively, vs 4%, P < .001). Within the high-volume quartile, the 10 hospitals with the nation's highest volumes had lower mortality rates than the remaining high-volume centers (2.1% vs 6.2%, P < .01). The strong association between institutional volume and mortality could not be attributed to patient case-mix differences or referral bias.

CONCLUSIONS

Although volume-outcome relationships have been reported for many complex surgical procedures, hospital experience is particularly important with pancreaticoduodenectomy. Patients considering this procedure should be given the option of care at a high-volume referral center.

Pancreatic-phase versus portal vein-phase helical CT of the pancreas: optimal temporal window for evaluation of pancreatic adenocarcinoma

OBJECTIVE

Our objective was to use helical CT to compare the enhancement attenuation values of pancreatic adenocarcinoma, adjacent normal pancreas, and critical vascular structures during the pancreatic phase and portal vein phase.

SUBJECTS AND METHODS

Forty-one patients with pathologically proven pancreatic adenocarcinoma underwent dual-phase thin-section dynamic helical CT using a pancreatic-phase and portal vein-phase protocol. The scan delay after initiation of the contrast bolus was 40 sec for the pancreatic phase and 70 sec for the portal vein phase. Attenuation values after i.v. contrast administration were calculated during both phases of scanning for normal pancreas, pancreatic tumor, celiac axis, superior mesenteric artery, superior mesenteric vein, splenic vein, and portal vein. Quantitative values were assessed using regions of interest.

RESULTS

Mean differences of enhancement between tumor and normal pancreas were significantly greater in the pancreatic phase (57 H) than the portal vein phase (35 H) (p = .0001). Enhancement values of all the critical vascular structures were also significantly greater in the pancreatic phase than the portal vein phase (p < .001).

CONCLUSION

With dynamic thin-section helical CT, pancreatic-phase scanning provides greater differences in contrast enhancement between normal pancreas and pancreatic tumor and between pancreatic tumors and surrounding critical vascular structures than does portal vein-phase scanning.

Measurement of pS2 protein in pancreatic cyst fluids. Evidence for a potential role of pS2 protein in the pathogenesis of mucinous cystic tumors

CONCLUSION

Elevated levels of the growth factor pS2 protein in the cyst fluids of mucinous cystic tumors correlate with earlier observations using immunohistochemical techniques showing that pS2 protein is expressed by these tumors. The markedly elevated levels of pS2 protein compared to normal plasma values suggest that this growth factor may be important in the pathogenesis of pancreatic mucinous cystic tumors.

BACKGROUND

Cystic lesions of the pancreas include inflammatory pseudocysts, serous cystadenomas, and mucinous cystic tumors, some of which are malignant. Previous studies using immunohistochemical techniques have shown that virtually all pancreatic mucinous tumors express pS2 protein. pS2 protein is a growth factor that is believed to be important in the normal process of inflammation and repair. We measured pS2 protein and other growth factors in pancreatic cyst fluids to assess their potential pathophysiologic and diagnostic significance.

METHODS

Levels of pS2 protein were measured in 54 pancreatic cyst fluids by radioimmunoassay. The growth factors, epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), and insulin-like growth factors I and II (IGF-I, IGF-II) were measured in 22 cyst fluids using commercial immunoassays.

RESULTS

Mucinous cysts exhibited significantly higher levels of cyst fluid pS2 protein than nonmucinous lesions, including pseudocysts and serous cystadenomas (median: 78,303 pg/mL; range: 218-361,176 pg/mL vs median: 886 pg/mL; range: 0-14,206 pg/mL; p = 0.0001). The level of pS2 in mucinous tumors was markedly higher than plasma values (median: 392 pg/mL). Levels of pS2 protein in malignant mucinous lesions tended to be higher than those in benign mucinous cysts, but this difference was not statistically significant (median: 88,817 vs 64,350 pg/mL; p = 0.159). Levels of other growth factors, including EGF, TGF-alpha, IGF-I, and IGF-II, did not discriminate among the different cyst types, and the values were within normal plasma ranges.

Intraoperatic electron beam irradiation in pancreatic cancer

Intraoperative electron beam radiation therapy (IOERT) is a technique in which a single high fraction radiation treatment is administered at the time of surgery. Using IOERT, the total radiation dose delivered to a tumor can be increased since sensitive normal tissues are removed from the radiation field during the surgical procedure. Furthermore, while the biologic effectiveness of this single fraction is incompletely understood, it is believed to be equivalent to that of a dose at least two times greater given by means of conventional fractionation. IOERT may improve local tumor control in patients with resectable or locally advanced pancreatic cancer. At the Massachusetts General Hospital (MGH), IOERT is being investigated in the management of pancreatic cancer as a boost treatment in combination with external beam radiation, surgery and chemotherapy.

Débridement and closed packing for the treatment of necrotizing pancreatitis

OBJECTIVE

To evaluate the results of débridement and closed packing for necrotizing pancreatitis and to determine the optimal timing of surgical intervention based on patient outcomes.

METHODS

Between February 1990 and November 1996, 64 consecutive patients with necrotizing pancreatitis were treated with necrosectomy followed by closed packing of the cavity with stuffed Penrose and closed suction drains. The mean APACHE II score immediately before surgery was 9, and 31% of the patients had organ failure. Patients were stratified with an outcome score based on death and major complications; this was correlated with the timing of surgical intervention. The data were then subjected to cut-point analysis by sequential group comparison.

RESULTS

Patients underwent surgery a median of 31 days after diagnosis. Fifty-six percent had infected necrosis. The mortality rate was 6.2% and was no different in infected or sterile necrosis. Eleven patients required a second surgical procedure and 13 required percutaneous drainage; a single surgical procedure sufficed in 69%. Enteric fistulae occurred in 16% of patients. The mean hospital stay after surgery was 41 days, and the interval until return to regular activities was 147 days. A significant negative correlation between duration of pancreatitis and outcome scores was found, and sequential group comparison demonstrated that the change point at which significantly better outcomes were encountered was day 27.

CONCLUSION

Débridement of pancreatic necrosis followed by closed packing and drainage is accomplished with a low mortality rate and reduced rates of complications and second surgical procedures. Although intervention is best deferred until the demarcation of necrosis is complete, delay beyond the fourth week confers no additional advantage.