Pancreas Solid Tumors

Solid tumors of the pancreas encompass a variety of diagnoses with treatments ranging from observation to major abdominal surgery. Pancreatic ductal adenocarcinoma remains one of the most common and most lethal of these differential of diagnoses and requires a multimodality approach through a multidisciplinary team of specialists. This article reviews the classification, clinical presentation, and workup in differentiating solid tumors of the pancreas and serves as an additional tool for general surgeons faced with such a clinical finding, from a surgical oncology perspective.

A Novel Reconstruction Technique During Pancreaticoduodenectomy After Roux-En-Y Gastric Bypass: How I do It

The altered anatomy in patients after bariatric surgery who have undergone a Roux-en-Y gastric bypass may pose a technical challenge for surgical removal of the pancreatic head. We treat patients with pancreas cancer with multimodality therapy in a neoadjuvant fashion followed by pancreaticoduodenectomy (PD). In patients with Roux-en-Y gastric bypass anatomy, the gastric remnant is preserved and used for pancreaticogastrostomy reconstruction and subsequently drained by the same jejunal limb used for the hepaticojejunostomy. This method of reconstruction takes advantage of the previous surgically altered anatomy and avoids the morbidity of a gastric remnant resection at the time of PD.

Techniques of Vascular Resection and Reconstruction in Pancreatic Cancer

Multimodality therapy has become the standard approach for the treatment of pancreatic cancer. With improved response rates to newer chemotherapeutic agents, tumors that used to be considered unresectable are now being considered for operation. Neoadjuvant therapy for borderline resectable pancreatic cancer is considered standard of care and venous resection/reconstruction is no longer controversial. Arterial resection and reconstruction in select patients has also proven to be safe when done in highly specialized centers by high-volume surgeons. This article reviews indications for, and technical aspects of, vascular resection/reconstruction and shunting procedures during pancreatectomy, including critical elements of perioperative care.

Radiotherapy for intrahepatic cholangiocarcinoma: An analysis of the National Cancer Database

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Background: The role of radiotherapy (RT) for surgically resected intrahepatic cholangiocarcinoma (ICC) remains poorly defined. Radiotherapy is often considered when a positive resection margin exists. The present study sought to examine the impact of radiotherapy following liver resection. Methods: Patients with early stage ICC, who underwent surgical resection, were identified from the National Cancer Database (1998-2011). Patients were stratified by resection margin status and receipt of RT. Survival was analyzed by Kaplan-Meier method and a multivariate regression model was used to identify predictors of survival. Results: A total of 2,182 patients were identified. R0 status was obtained in 1,624 patients (74.4%). RT was delivered to 405 patients (R0=209, R1/R2=196). In the R1/R2 group, 196 patients received RT vs. 362 R1/R2 patients that did not receive RT. Survival for R0 vs. R1/R2 was 32m vs. 16.5m (p<0.001). RT appeared to trend toward improving survival for R1/R2 patients, though this was not significant (20.4m vs. 14.5m, p=0.191). In a multivariate model accounting for age, sex, comorbidities, disease stage and resection margins, RT was not a predictor of survival. Negative predictors of survival included age>65years (Hazards Ratio [HR]: 1.20 (95%CI: 1.04-1.39), p=0.013), and positive resection margins (HR: 1.95 (95%CI: 1.65-2.30), p<0.001). Female sex was the only positive predictor of survival identified (HR: 0.76 (95%CI: 0.65 -0.88), p<0.001). Conclusions: Surgical resection with negative margins provides the best outcome for patients with ICC. Radiotherapy does not appear to significantly impact survival in patients with positive resection margins.

Waveform modulation of negative-pressure wound therapy in the murine model

BACKGROUND

Negative-pressure wound therapy applied with a porous foam interface has been shown to accelerate granulation-tissue formation when a cyclic application mode of suction is applied, but the optimal waveform has not been determined. The authors hypothesized that changes in the suction waveform applied to wounds would modulate the biological response of granulation tissue formation.

METHODS

A vacuum-assisted closure device (Kinetic Concepts, Inc., San Antonio, Texas) was applied to full-thickness wounds in 48 male diabetic mice (C57BL/KsJ-Lepr db), which were treated with six different waveforms: square waveforms of 125 mmHg of suction for 2 minutes, alternating with 50 mmHg of suction for 2 minutes, 5 minutes, or 10 minutes; triangular waveform with a 7-minute period oscillating between 50 and 125 mmHg; and static suction at 125 mmHg or static suction at 0 mmHg (occlusive dressing). Wounds were quantitatively evaluated for granulation tissue thickness as well as the number of proliferating cells and the number of blood vessels of the newly formed granulation tissue.

RESULTS

At 7 days, the continuous and triangular waveforms induced the thickest granulation tissue, with high rates of cellular proliferation and blood vessel counts compared with square wave and occlusive dressing control wounds. Decreasing square waveform frequency significantly increased granulation tissue thickness, cellular proliferation, and blood vessel counts.

CONCLUSIONS

Waveform modulation has a significant effect on granulation tissue formation, angiogenesis, and cellular proliferation in excisional wounds in diabetic mice. The rapid change in pressure seen in our square wave model may be detrimental to granulation tissue formation.

Controlled induction of distributed microdeformation in wounded tissue via a microchamber array dressing

Mechanical stimuli are known to play an important role in determining the structure and function of living cells and tissues. Recent studies have highlighted the role of mechanical signals in mammalian dermal wound healing. However, the biological link between mechanical stimulation of wounded tissue and the subsequent cellular response has not been fully determined. The capacity for researchers to study this link is partially limited by the lack of instrumentation capable of applying controlled mechanical stimuli to wounded tissue. The studies outlined here tested the hypothesis that it was possible to control the magnitude of induced wound tissue deformation using a microfabricated dressing composed of an array of open-faced, hexagonally shaped microchambers rendered in a patch of silicone rubber. By connecting the dressing to a single vacuum source, the underlying wounded tissue was drawn up into each of the microchambers, thereby inducing tissue deformation. For these studies, the dressings were applied to full-thickness murine dermal wounds with 200 mmHg vacuum for 12 h. These studies demonstrated that the dressing was capable of inducing wound tissue deformation with values ranging from 11 to 29%. Through statistical analysis, the magnitude of the induced deformation was shown to be a function of both microchamber height and width. These results demonstrated that the dressing was capable of controlling the amount of deformation imparted in the underlying tissue. By allowing the application of mechanical stimulation with varying intensities, such a dressing will enable the performance of sophisticated mechanobiology studies in dermal wound healing.

The inflammatory response after an epidermal burn depends on the activities of mouse mast cell proteases 4 and 5

A second-degree epidermal scald burn in mice elicits an inflammatory response mediated by natural IgM directed to nonmuscle myosin with complement activation that results in ulceration and scarring. We find that such burn injury is associated with early mast cell (MC) degranulation and is absent in WBB6F1-Kit(W)/Kit(Wv) mice, which lack MCs in a context of other defects due to a mutation of the Kit receptor. To address further an MC role, we used transgenic strains with normal lineage development and a deficiency in a specific secretory granule component. Mouse strains lacking the MC-restricted chymase, mouse MC protease (mMCP)-4, or elastase, mMCP-5, show decreased injury after a second-degree scald burn, whereas mice lacking the MC-restricted tryptases, mMCP-6 and mMCP-7, or MC-specific carboxypeptidase A3 activity are not protected. Histologic sections showed some disruption of the epidermis at the scald site in the protected strains suggesting the possibility of topical reconstitution of full injury. Topical application of recombinant mMCP-5 or human neutrophil elastase to the scalded area increases epidermal injury with subsequent ulceration and scarring, both clinically and morphologically, in mMCP-5-deficient mice. Restoration of injury requires that topical administration of recombinant mMCP-5 occurs within the first hour postburn. Importantly, topical application of human MC chymase restores burn injury to scalded mMCP-4-deficient mice but not to mMCP-5-deficient mice revealing nonredundant actions for these two MC proteases in a model of innate inflammatory injury with remodeling.