Development of a pancreatic tumor animal model and evaluation of NOTES tumor enucleation

The Oncopig Cancer Model: An Innovative Large Animal Translational Oncology Platform

Despite an improved understanding of cancer molecular biology, immune landscapes, and advancements in cytotoxic, biologic, and immunologic anti-cancer therapeutics, cancer remains a leading cause of death worldwide. More than 8.2 million deaths were attributed to cancer in 2012, and it is anticipated that cancer incidence will continue to rise, with 19.3 million cases expected by 2025. The development and investigation of new diagnostic modalities and innovative therapeutic tools is critical for reducing the global cancer burden. Toward this end, transitional animal models serve a crucial role in bridging the gap between fundamental diagnostic and therapeutic discoveries and human clinical trials. Such animal models offer insights into all aspects of the basic science-clinical translational cancer research continuum (screening, detection, oncogenesis, tumor biology, immunogenicity, therapeutics, and outcomes). To date, however, cancer research progress has been markedly hampered by lack of a genotypically, anatomically, and physiologically relevant large animal model. Without progressive cancer models, discoveries are hindered and cures are improbable. Herein, we describe a transgenic porcine model—the Oncopig Cancer Model (OCM)—as a next-generation large animal platform for the study of hematologic and solid tumor oncology. With mutations in key tumor suppressor and oncogenes, TP53^R167H and KRAS^G12D, the OCM recapitulates transcriptional hallmarks of human disease while also exhibiting clinically relevant histologic and genotypic tumor phenotypes. Moreover, as obesity rates increase across the global population, cancer patients commonly present clinically with multiple comorbid conditions. Due to the effects of these comorbidities on patient management, therapeutic strategies, and clinical outcomes, an ideal animal model should develop cancer on the background of representative comorbid conditions (tumor macro- and microenvironments). As observed in clinical practice, liver cirrhosis frequently precedes development of primary liver cancer or hepatocellular carcinoma. The OCM has the capacity to develop tumors in combination with such relevant comorbidities. Furthermore, studies on the tumor microenvironment demonstrate similarities between OCM and human cancer genomic landscapes. This review highlights the potential of this and other large animal platforms as transitional models to bridge the gap between basic research and clinical practice.

Diagnosis of lymphoma by endoscopic ultrasound-assisted transendoscopic direct retroperitoneal lymph node biopsy: A case report (with video)

Since its introduction in the early 1990s, endoscopic ultrasound-assisted fine-needle aspiration (EUS-FNA) has been used for sampling of extraintestinal mass lesions and peri-intestinal lymphadenopathy. Although EUS-FNA is highly accurate, lymphomas can be challenging to diagnose using EUS-FNA. We present the case of a 60-year-old male who had experienced upper abdominal discomfort for 1 month. Computerized tomography (CT) examination revealed multiple soft-tissue shadows located above the pancreatic body. The biggest shadow had a cross-sectional area of 7.7 cm × 7.2 cm. Positron emission tomography-CT (PET-CT) imaging showed increased uptake of (18)F-FDG by these soft-tissue shadows. To investigate further, EUS was performed and it revealed the presence of multiple hypoechoic round lymph nodes. During the procedure, EUS-FNA was performed, but only a few dyskaryotic cells were observed by cytological evaluation. EUS-assisted retroperitoneoscopy and lymph node biopsy were performed to obtain more tissue for immunohistochemical analysis and subclassification of lymphoma. Finally, the patient was diagnosed with non-Hodgkin lymphoma, germinal center B-cell-like diffuse large B-cell lymphoma by this technique. EUS-assisted transendoscopic retroperitoneal lymph node biopsy is an alternative procedure for the diagnosis of lymphomas.

A novel, new robotic platform for natural orifice distal pancreatectomy

Laparoendoscopic technology has revolutionized the practice of surgery; however, surgeons have not widely accepted laparoscopic techniques for pancreatic surgeries due to the complexity of the operation. Natural orifice transluminal endoscopic surgery (NOTES) offers a great new potential for pancreatic procedures, with early data showing benefits of reduced visible scarring and the potential for decreased wound infections, hernias, pain, and postoperative complications. However, there are significant limitations to the currently used flexible endoscopy tools, including a diminished visual field, spatial orientation and tissue manipulation issues, and 2-dimensional visual feedback. We have adopted a novel snake-like robot, the minimally invasive cardiac surgery (MICS) robot, which addresses these issues. In the current pilot study, the MICS robot was evaluated for transrectal distal pancreas exploration and resection in 2 nonsurvival porcine models. Abdominal navigation and accessing the pancreas was investigated in the first pig, and based on its success, pancreas resection was studied in pig 2. The MICS robot was successful in accessing and visualizing the right upper, left upper, and left lower quadrants of the abdomen in pig 1 and was able to perform a successful complex NOTES procedure with distal pancreas resection in pig 2, with only minimal laparoscopic retraction assistance. In conclusion, preliminary results showing the MICS robot in natural orifice distal pancreatectomy are positive. Enhancements to optics and instrumentation will help further increase the usability in pancreatic interventions. Future indications may include transgastric NOTES approaches, endoluminal procedures, and single-port applications.

Single-incision versus conventional laparoscopic distal pancreatectomy: a single-institution case-control study

PURPOSE

Laparoscopic distal pancreatectomy is becoming increasingly established at specialized surgical institutions worldwide. The purpose of this study was to compare single-incision laparoscopic distal pancreatectomy (panLESS) with conventional laparoscopic distal pancreatectomy (panLAP) to assess feasibility and 30-day morbidity.

METHODS

Eight consecutive patients who underwent panLESS were matched with patients who underwent panLAP in the same time period. Matching criteria were age, body mass index, and American Society of Anesthesiologists score. Feasibility was based on tumor size, operative time, intraoperative bleeding, resection status, and hospital stay. Thirty-day morbidity was defined by the revised Accordion Classification system and the International Study Group on Pancreatic Fistula definition.

RESULTS

Over a 19-month period, 8 and 16 patients were identified for panLESS and panLAP, respectively. There were no significant differences in tumor size, operative time, intraoperative bleeding, resection status, and hospital stay between the two groups. Surgical complications developed in four panLESS patients and five panLAP patients, and out of which, two patients from each group developed a postoperative pancreatic fistula (grade B).

CONCLUSIONS

This study indicates that panLESS is comparable to panLAP in terms of feasibility. More experience is needed to define what role single-incision distal pancreatectomy should have in minimal invasive pancreatic surgery.

Laparoscopic pancreatectomy for malignancy

Utilization of laparoscopic techniques for resection of the pancreas has slowly gained acceptance in specific situations and is now being applied to more challenging endeavors, such as pancreaticoduodenectomy for cancer. This review provides a summary of laparoscopic applications for pancreatic malignancy, with specific attention to the most common methods of pancreatic resection and their respective oncologic outcomes, including margin status, lymph node retrieval, and survival.