Peter Muscarella

Natural-orifice transgastric endoscopic peritoneoscopy in humans: Initial clinical trial

BackgroundNatural-orifice translumenal endoscopic surgery (NOTES) is a possible advancement for surgical interventions. We initiated a pilot study in humans to investigate feasibility and develop the techniques and technology necessary for NOTES. Reported herein is the first human clinical trial of NOTES, performing transoral transgastric diagnostic peritoneoscopy.MethodsPatients were scheduled to undergo diagnostic laparoscopic evaluation of a pancreatic mass. The findings of traditional laparoscopy were recorded by anatomical abdominal quadrant. A second surgeon, blinded to the laparoscopic findings, performed transgastric peritoneoscopy. Diagnostic findings between the two methods were compared and operative times and clinical course were recorded. Definitive care was based on findings at diagnostic laparoscopy.ResultsTen patients completed the protocol with an average age of 67.6 years. All patients underwent diagnostic laparoscopy followed by successful transgastric access and diagnostic endoscopic peritoneoscopy. The average time of diagnostic laparoscopy was 12.3 minutes compared to 24.8 minutes for the transgastric route. Transgastric abdominal exploration corroborated the decision to proceed to open exploration made during traditional laparoscopic exploration in 9 of 10 patients. Peritoneal or liver biopsies were obtained in four patients by traditional laparoscopy and in one patient by the transgastric access route. Findings were confirmed by laparotomy in nine patients. Eight patients underwent pancreaticoduodenectomy and two underwent palliative gastrojejunostomy and/or hepaticojejunostomy.ConclusionsTransgastric diagnostic peritoneoscopy is safe and feasible. This study demonstrates the initial steps of NOTES in humans, providing a potential platform for incisionless surgery. Technical issues, including instrumentation, visualization, intra-abdominal manipulation, and gastric closure need further development.

A Randomized Prospective Multicenter Trial of Pancreaticoduodenectomy With and Without Routine Intraperitoneal Drainage

Objective:To test by randomized prospective multicenter trial the hypothesis that pancreaticoduodenectomy (PD) without the use of intraperitoneal drainage does not increase the frequency or severity of complications. Background:Some surgeons have abandoned the use of drains placed during pancreas resection. Methods:We randomized 137 patients to PD with (n = 68, drain group) and without (n = 69, no-drain group) the use of intraperitoneal drainage and compared the safety of this approach and spectrum of complications between the 2 groups. Results:There were no differences between drain and no-drain cohorts in demographics, comorbidities, pathology, pancreatic duct size, pancreas texture, baseline quality of life, or operative technique. PD without intraperitoneal drainage was associated with an increase in the number of complications per patient [1 (0-2) vs 2 (1-4), P = 0.029]; an increase in the number of patients who had at least 1 ≥grade 2 complication [35 (52%) vs 47 (68%), P = 0.047]; and a higher average complication severity [2 (0-2) vs 2 (1-3), P = 0.027]. PD without intraperitoneal drainage was associated with a higher incidence of gastroparesis, intra-abdominal fluid collection, intra-abdominal abscess (10% vs 25%, P = 0.027), severe (≥grade 2) diarrhea, need for a postoperative percutaneous drain, and a prolonged length of stay. The Data Safety Monitoring Board stopped the study early because of an increase in mortality from 3% to 12% in the patients undergoing PD without intraperitoneal drainage. Conclusions:This study provides level 1 data, suggesting that elimination of intraperitoneal drainage in all cases of PD increases the frequency and severity of complications.

The genetics of pancreatic cancer

The genetic basis for invasive and preoneoplastic neoplasms of the exocrine and endocrine pancreas has been the subject of a number of investigations in recent years. The purpose of this paper was to briefly review and summarize the pertinent findings. High frequency changes associated with pancreatic adenocarcinomas include mutations of the k-ras oncogene, and inactivating alterations of the p53, p16, and DPC4 tumor suppressor genes. Hereditary syndromes that have a known predisposition for pancreatic adenocarcinoma development include hereditary pancreatitis, familial atypical multiple mole melanoma (FAMM) syndrome, Peutz-Jeghers syndrome, familial breast cancer (BRCA-2), hereditary nonpolyposis colorectal cancer syndrome (HNPCC), and Li-Fraumeni syndrome. The underlying genetic defects have been identified and are currently being studied. Germline mutations of the men-1 gene are responsible for the MEN-1 syndrome, known to be associated with pancreatic endocrine tumors. It appears that somatic mutations of the gene are present in at least a subset of sporadic tumors. In addition, alterations in the Rb/p16 pathway appear to be commonly associated with pancreatic endocrine tumors. Further characterization of pancreatic tumors will result in a better understanding of the cellular pathways involved in pancreatic tumorigenesis and holds promise to identify targets for novel diagnostic and therapeutic strategies.

NF-κB-mediated Pax7 dysregulation in the muscle microenvironment promotes cancer cachexia

Cachexia is a debilitating condition characterized by extreme skeletal muscle wasting that contributes significantly to morbidity and mortality. Efforts to elucidate the underlying mechanisms of muscle loss have predominantly focused on events intrinsic to the myofiber. In contrast, less regard has been given to potential contributory factors outside the fiber within the muscle microenvironment. In tumor-bearing mice and patients with pancreatic cancer, we found that cachexia was associated with a type of muscle damage resulting in activation of both satellite and nonsatellite muscle progenitor cells. These muscle progenitors committed to a myogenic program, but were inhibited from completing differentiation by an event linked with persistent expression of the self-renewing factor Pax7. Overexpression of Pax7 was sufficient to induce atrophy in normal muscle, while under tumor conditions, the reduction of Pax7 or exogenous addition of its downstream target, MyoD, reversed wasting by restoring cell differentiation and fusion with injured fibers. Furthermore, Pax7 was induced by serum factors from cachectic mice and patients, in an NF-κB-dependent manner, both in vitro and in vivo. Together, these results suggest that Pax7 responds to NF-κB by impairing the regenerative capacity of myogenic cells in the muscle microenvironment to drive muscle wasting in cancer.

Endoscopic management of stomal stenosis after Roux-en-Y gastric bypass

Background: In the United States, Roux-en-Y gastric bypass has evolved into the procedure of choice for clinically severe obesity. Stomal stenosis resulting in gastric outlet obstruction is a recognized complication. Endoscopic balloon dilation is often used to treat this condition. To evaluate the safety and efficacy of endoscopic management of stomal stenosis we evaluated our treatment methods and outcomes. Methods: The records of all patients undergoing Roux-en-Y gastric bypass from 1 July 2000 to 30 June 2002 were studied. Stenosis was defined as signs and symptoms of obstruction with inability to cannulate the gastrojejunostomy using an 8.5-mm diagnostic endoscope. Charts were reviewed and demographic data, operative course, symptoms, and outcomes were recorded. Results: A total of 562 patients underwent Roux-en-Y gastric bypass for obesity during the study period. Of these, 38 patients underwent endoscopic balloon dilation for stomal stenosis, for a stenosis rate of 6.8%. The average time from surgery to initial dilation was 7.7 weeks (range 3 to 24). The average number of dilations required was 2.1 (range one to six). The mean initial balloon size was 13 mm and the mean final balloon size was 16 mm. Two patients failed endoscopic dilation and proceeded to surgery, including one patient who developed pneumomediastinum and pneumothorax after dilation. All patients were relieved of their gastric outlet obstruction. The success rate for endoscopic balloon dilation was 95% with a 3% complication rate. Conclusions: In our experience, the rate of gastrojejunostomy stenosis following Roux-en-Y gastric bypass is 6.8%. Endoscopic balloon dilation is a safe and effective therapy for stomal stenosis with a high success rate. It should be considered an appropriate intervention with a low risk for reoperation.

Nonoxidative pentose phosphate pathways and their direct role in ribose synthesis in tumors: Is cancer a disease of cellular glucose metabolism?

Pentose phosphate pathways (PPP) are considered important in tumor proliferation processes because of their role in supplying tumor cells with reduced NADP and carbons for intracellular anabolic processes. Direct involvement of PPP in tumor DNA/RNA synthesis is not considered as significant as in lipid and protein syntheses. Currently, PPP activity in tumor cells is measured by lactate production, which shows a moderate activity: about 4% to 7% compared with glycolysis. Recent data generated in our laboratory indicate that PPP are directly involved in ribose synthesis in pancreatic adenocarcinoma cells, through oxidative steps (< 31%) and transketolase reactions (69%). These findings raise serious questions about the adequacy of lactate in measuring PPP activity in tumors. We hypothesize that ribose, not lactate, is the major product of PPP in tumor cells. Control of both oxidative and nonoxidative PPP may be critical in the treatment of cancer. PPP are substantially involved in the proliferation of human tumors, which raises the prospect of new treatment strategies targeting specific biochemical reactions of PPP by hormones related to glucose metabolism, controlling thiamine intake, the cofactor of the nonoxidative transketolase PPP reaction, or treating cancer patients with antithiamine analogues.

Pancreatic Resection in the Octogenarian: A Safe Option for Pancreatic Malignancy

BACKGROUND The incidence of pancreatic cancer is age related; patients older than the age of 65 represent 60% of all cases. We assessed our institutions experience and outcomes with pancreatic resection for malignancy in patients in their ninth decade. STUDY DESIGN We reviewed records of patients undergoing pancreatic resection for malignancy at our institution between 1990 and 2007. Demographics, laboratory, treatment, and outcomes data were gathered. Comparisons were made between patients older and younger than the age of 80. Survival was analyzed using the Kaplan-Meier method and comparisons between groups were performed using the log-rank test. Regression methods were used to evaluate predictors of outcomes. RESULTS There were 517 pancreatic resections for cancer reviewed. Of these, 27 patients were 80 years or older (age range 80 to 91 years), compared with 490 patients less than 80 (range 20 to 79 years). The distribution of clinical characteristics was similar between the 2 groups. The majority of patients undergoing pancreatic resection harbored a mass in the head of the pancreas, so the most common procedure was pancreaticoduodenectomy (n = 398, 78%). There were no significant differences in complication rates for younger and older groups (59% vs 52%, respectively, p = 0.4), median length of stay (11 vs 12 days, p = 0.33), or perioperative mortality rates (3.7% vs 3.7%, p = 1.0). Overall survival between the 2 groups was similar (21.9 vs 33.3 months, p = 0.18). CONCLUSIONS Pancreatectomy for malignancy is a safe option for the elderly. Patients older than age 80 achieved similar results, with similar rates of perioperative complications and mortality. Pancreatectomy for cancer offers a similar survival benefit in both groups.

Outcome analysis of long-term survivors following pancreaticoduodenectomy☆☆☆

The long-term sequelae of pancreaticoduodenectomy are not completely understood. In the present study nutritional status, pancreatic function, and subjective quality-of-life parameters were evaluated in 45 patients who had previously undergone either pylorus-preserving pancreaticoduodenectomy (PPPD) or standard pancreaticoduodenectomy (SPD). Quality-of-life parameters, as measured by the Short Form-36 health survey, demonstrated no significant differences between the subgroups and normal control subjects in six of the eight domains for physical and mental health. Patients who had undergone SPD were noted to have significantly lower scores for general health and vitality than either age-matched control subjects or those who had undergone PPPD. No differences in nutritional parameters or indicators of pancreatic exocrine function between the two groups were identified. An elevated hemoglobin Alc value was seen in only one patient who was not diabetic preoperatively. Our data indicate that long-term survivors of pancreaticoduodenectomy generally feel as good as their normal counterparts, although SPD may result in some health satisfaction deficits. Nutritional status and pancreatic exocrine function are not improved in patients undergoing a pylorus-preserving procedure, and postoperative pancreatic endocrine dysfunction is unusual in both groups.

A review of 130 humans enrolled in transgastric NOTES protocols at a single institution.

BackgroundThe methodology of Natural Orifice Translumenal Endoscopic Surgery (NOTES) has been validated in both human and animal models. Herein is a discussion of our experience gained from the initial 130 patients enrolled in transgastric pre-NOTES and NOTES protocols at our institution.MethodsA retrospective review of our research database was performed for all patients enrolled in NOTES protocols. The infectious risk of a gastrotomy with and without a NOTES procedure was assessed in 100 patients. Eighty patients completed a true NOTES protocol looking at staging, access, and insufflation with select patients evaluating the potential for bacterial contamination of the abdominal compartment.ResultsA total of 130 patients have completed pre-NOTES and NOTES protocols at our institution. We observed no clinically significant contamination of the abdomen secondary to transgastric procedures in 100 patients. Diagnostic transgastric endoscopic peritoneoscopy (DTEP) was completed in 20 patients with pancreatic head masses and found to have a 95% concordance with laparoscopic exploration for assessment of peritoneal metastases. Blind endoscopic gastrotomy and DTEP were evaluated in 40 patients who underwent laparoscopic Roux-en-Y gastric bypass procedures (LSRYGB) and were found to be safe, reliable, and without a clinically significant risk of contamination. Endoscopic peritoneal insufflation was successfully established and correlated with standard laparoscopic insufflation in 20 patients.ConclusionsTransgastric NOTES is a safe alternative approach to accessing the peritoneal cavity in humans. The risk of bacterial contamination secondary to peroral and transgastric access is clinically insignificant. A device for the facile closure of the gastric defect is the sole factor limiting institution of this methodology as a standalone technique.

Cytoreduction Results in High Perioperative Mortality and Decreased Survival in Patients Undergoing Pancreatectomy for Neuroendocrine Tumors of the Pancreas

We reviewed our experience with pancreatectomy for neuroendocrine tumors (NE) to determine outcomes after R0/R1 or R2 resection and compare them to patients in whom resection was not attempted. Data were reviewed for all patients presenting with NE tumors of the pancreas between 1990 and 2005. Kaplan-Meier survival curves were compared by log-rank analysis. Multivariate analysis was completed using Cox proportional hazards to identify risk factors for poor survival after resection. Of 120 patients, 65 (54%) had functional tumors. Resection was undertaken in 83: distal pancreatectomy in 41, pancreaticoduodenectomy in 27, enucleation in 14, and central pancreatectomy in 1. Survival was significantly longer after resection (91 months versus 24, P<0.001). R0/R1 resection was accomplished in 64 (77%) and resulted in lower perioperative mortality (2% versus 21%, P<0.01) and longer survival (112 months versus 24, P<0.001) compared to R2 resection. Survival after R2 resection was no better than after no resection. Factors predictive of decreased survival were moderate/poor differentiation, R2 resection, and high-risk features. Long-term survival is possible following complete resection for NE tumors of the pancreas. However, cytoreduction resulting in incomplete tumor removal carries significant perioperative mortality without long-term survival benefit and should be discouraged.