Flexible CO2 laser and submucosal gel injection for safe endoluminal resection in the intestines.

BACKGROUND: The CO(2) laser's unique wavelength of 10.6 µm has the advantage of being readily absorbed by water but historically limited it to line-of-sight procedures. Through recent technological advances, a flexible CO(2) laser fiber has been developed and holds promise for endoluminal surgery. We examined whether this laser, along with injection of a water-based gel in the submucosal space, will allow safe dissection of the intestines and enhance the potential of this tool for minimally invasive surgery. METHODS: Using an ex vivo model with porcine intestines, spot ablation was performed with the flexible CO(2) laser at different power settings until transmural perforation. Additionally, excisions of mucosal patches were performed by submucosal dissection with and without submucosal injection of a water-based gel. RESULTS: With spot ablation at 5 W, none of the specimens was perforated by 5 min, which was the maximum recorded time. The time to perforation was significantly shorter with increased laser power, and gel pretreatment protected the intestines against spot ablation, increasing the time to perforation from 6 to 37 s at 10 W and from 1 to 7 s at 15 W. During excision of mucosal patches, 56 and 83% of untreated intestines perforated at 5 and 10 W, respectively. Gel pretreatment prior to excision protected all intestines against perforation. These specimens were verified to be intact by inflation with air to over 100 mmHg. Furthermore, excision of the mucosal patch was complete in gel-pretreated specimens, whereas 22% of untreated specimens had residual islands of mucosa after excision. CONCLUSION: The flexible CO(2) laser holds promise as a precise dissection and cutting tool for endoluminal surgery of the intestines. Pretreatment with a submucosal injection of a water-based gel protects the intestines from perforation during ablation and mucosal dissection.

Insertion of the human sodium iodide symporter to facilitate deep tissue imaging does not alter oncolytic or replication capability of a novel vaccinia virus.

INTRODUCTION: Oncolytic viruses show promise for treating cancer. However, to assess therapeutic efficacy and potential toxicity, a noninvasive imaging modality is needed. This study aimed to determine if insertion of the human sodium iodide symporter (hNIS) cDNA as a marker for non-invasive imaging of virotherapy alters the replication and oncolytic capability of a novel vaccinia virus, GLV-1h153. METHODS: GLV-1h153 was modified from parental vaccinia virus GLV-1h68 to carry hNIS via homologous recombination. GLV-1h153 was tested against human pancreatic cancer cell line PANC-1 for replication via viral plaque assays and flow cytometry. Expression and transportation of hNIS in infected cells was evaluated using Westernblot and immunofluorescence. Intracellular uptake of radioiodide was assessed using radiouptake assays. Viral cytotoxicity and tumor regression of treated PANC-1tumor xenografts in nude mice was also determined. Finally, tumor radiouptake in xenografts was assessed via positron emission tomography (PET) utilizing carrier-free 124I radiotracer. RESULTS: GLV-1h153 infected, replicated within, and killed PANC-1 cells as efficiently as GLV-1h68. GLV-1h153 provided dose-dependent levels of hNIS expression in infected cells. Immunofluorescence detected transport of the protein to the cell membrane prior to cell lysis, enhancing hNIS-specific radiouptake (P < 0.001). In vivo, GLV-1h153 was as safe and effective as GLV-1h68 in regressing pancreatic cancer xenografts (P < 0.001). Finally, intratumoral injection of GLV-1h153 facilitated imaging of virus replication in tumors via 124I-PET. CONCLUSION: Insertion of the hNIS gene does not hinder replication or oncolytic capability of GLV-1h153, rendering this novel virus a promising new candidate for the noninvasive imaging and tracking of oncolytic viral therapy.

Surgical management of tumors invading the aorta and major arterial structures.

BACKGROUND: This study investigates surgical management of tumors arising from or involving the aorta and major arterial structures. METHODS: A retrospective single institutional review was conducted of patients undergoing arterial resection for tumors involving the aorta or major arterial structures between January 1992 and May 2009 at a tertiary care center. Patients with tumors abutting arteries without necessitating resection and those involving only venous structures were excluded. Patients were analyzed in groups by vessel involvement: aorta, carotid, external/common iliac, internal iliac, superficial femoral, and miscellaneous. RESULTS: Sixty patients were identified and included for review. The iliac arteries were most often resected, and sarcomatous pathology was most common (37 patients, 62%). Twelve patients underwent aortic resection, with eight (67%) of these undergoing graft reconstruction, one (8%) graft patch, and two (17%) primary repair. None of the 17 patients undergoing internal iliac resection underwent reconstruction, whereas the majority of patients in all other groups underwent reconstruction. Thirty-day mortality (TDM) was 0% in all groups, except the aortic (2/12, 17% TDM), and internal iliac arteries (1/17, 6% TDM). Estimated blood loss varied widely and was not significantly different between vessel groups (p = 0.280). Overall, 44 of 60 (73%) patients had negative margins. Fourteen patients (23%) returned to the operating room, most for wound infection or dehiscence. Mean follow-up was 20.25 months (range: 0.5-122.0 months, SD: 23 months). Forty patients were followed up for more than 1 year. Thus, with an overall median follow-up of 12.25 months, overall survival was 60% with disease-free survival of 40%. CONCLUSIONS: Resection of tumors involving the aorta and major arterial structures provides a reasonable option for treatment, but with significant perioperative morbidity. In selected patients, this aggressive intervention should be considered.

Management of disappearing colorectal hepatic metastases.

Disappearance of liver lesions during neoadjuvant chemotherapy is common and is the basis for the increasing number of patients suitable for potentially curative hepatectomy in patients with hepatic colorectal metastases. Many of the liver lesions disappearing on radiologic evaluation after successful chemotherapy for metastatic colorectal cancer are still present and alive. In patients with only some disappearing lesions, exploration should be undertaken to thoroughly evaluate all sites of previous disease. Because many small residual lesions are scars and complete pathologic responses, treatment should include not only complete treatment of all remaining lesions but also parenchymal conservation techniques such as ablations and limited resections. For patients with completely disappearing lesions, the standard therapy is still exploration and direct intraoperative assessment. However, if the patient chooses observation in the setting of negative CEA, MRI, and PET, close follow-up should be undertaken to avoid missing treatable and resectable recurrences.

Molecular network, pathway, and functional analysis of time-dependent gene changes associated with pancreatic cancer susceptibility to oncolytic vaccinia virotherapy.

BACKGROUND: Pancreatic cancer is a fatal disease associated with resistance to conventional therapies. This study aimed to determine changes in gene expression patterns associated with infection and susceptibility of pancreatic cancer cells to an oncolyticvaccinia virus, GLV-1h153, carrying the human sodium iodide symporter for deep tissue imaging of virotherapy. METHODS: Replication and susceptibility of pancreatic adenocarcinoma PANC-1 cells to GLV-1h153 was confirmed with replication and cytotoxicity assays. PANC-1 cells were then infected with GLV-1h153 and near-synchronous infection confirmed via flow cytometry of viral-induced green fluorescent protein (GFP) expression. Six and 24 hours after infection, three samples of each time point were harvested, and gene expression patterns assessed using HG-U133A cDNA microarray chips as compared to uninfected control. Differentially expressed genes were identified using Bioconductor LIMMA statistical analysis package. A fold change of 2.0 or above was used as a cutoff, with a P value of 0.01. The gene list was then analyzed using Ingenuity Pathways Analysis software. RESULTS: Differential gene analysis revealed a total of 12,412 up- and 11,065 downregulated genes at 6 and 24 hours postinfection with GLV-1h153 as compared to control. At 6 hours postinfection. A total of 139 genes were either up or downregulated >twofold (false discovery rate < 0.05), of which 124 were mapped by Ingenuity Pathway Analysis (IPA). By 24 hours postinfection, a total of 5,698 genes were identified and 5,563 mapped by IPA. Microarray revealed gene expression changes, with gene networks demonstrating downregulation of processes such as cell death, cell cycle, and DNA repair, and upregulation of infection mechanisms (P < 0.01). Six hours after infection, gene changes involved pathways such as HMGB-1, interleukin (IL)-2, IL-6, IL-8, janus kinase/signal tranducer and activator of transcription (JAK/STAT), interferon, and ERK 5 signaling (P < 0.01). By 24 hours, prominent pathways included P53- and Myc-induced apoptotic processes, pancreatic adenocarcinoma signaling, and phosphoinositide 3-kinase/v-akt murine thymoma vial oncogene homolog 1 (PI3/AKT) pathways. CONCLUSIONS: Our study reveals the ability to assess time-dependent changes in gene expression patterns in pancreatic cancer cells associated with infection and susceptibility to vaccinia viruses. This suggests that molecular assays may be useful to develop safer and more efficacious oncolyticvirotherapies and support the idea that these treatments may target pathways implicated in pancreatic cancer resistance to conventional therapies.

Real-time fluorescence imaging of abdominal, pleural, and lymphatic metastases.

Virally-directed fluorescence imaging has the potential to revolutionize intra-operative oncologic staging and tumor resection. Many viruses genetically engineered to specifically infect tumor cells as cancer therapy can be further modified to have a visible marker gene for cancer staging. In this chapter, we describe such a herpes simplex virus (HSV) modified to be detected by fluorescence. Other viruses so designed can be similarly used in cancer detection and staging. Replication-competent, tumor-specific HSV NV1066 expresses green fluorescent protein (GFP) in infected cancer cells. One single dose of NV1066 administered via intratumor, intracavitary, or systemic injection can spread within and across body cavities to target tumor cells while sparing normal tissue cells from infection. Tumors otherwise invisible by conventional laparoscopy appear green with the use of an endoscope equipped with a fluorescent filter. Furthermore, with GFP expression easily visualized by stereomicroscopy, microscopic, and pathologic analysis is significantly enhanced. This chapter addresses NV1066-directed visualization of peritoneal, pleural, and lymphatic metastases. This chapter also provides protocols for the production of tumor models in various body cavities in rodents.

Increased risk of neoplasm in appendicitis treated with interval appendectomy: single-institution experience and literature review.

Appendicitis is a common diagnosis encountered by the acute care surgeon. Management of complicated appendicitis is controversial and often involves initial nonoperative therapy with interval appendectomy. This study reviews single-institutional experience with management of complicated appendicitis with interval appendectomy and addresses an unusually high occurrence of incidental appendiceal malignancies observed with a review of relevant literature. A retrospective review of all diagnoses of appendicitis was performed over 5 years at a tertiary care center. Patient demographics, time to surgery, operative technique, pathologic diagnosis, and clinical outcomes were examined. Three hundred fifteen patients were diagnosed with acute appendicitis. Of these, 24 (7.6%) were deemed complicated and did not undergo immediate appendectomy, and 18 ultimately underwent appendectomy at our institution and were included in analysis. There were no statistical demographic or symptomatic differences between the immediate and interval appendectomy patients. Ninety-nine per cent of the immediate appendectomy patients were treated laparoscopically; 78 per cent of the interval group underwent attempted laparoscopic treatment with 56 per cent completed without conversion to open (P < 0.01). Neoplasms were discovered in 1 per cent of the acute appendectomy group and 28 per cent of the interval appendectomy group (P < 0.0001). Two of the three neoplasms in the acute group were carcinoid, whereas three of the five neoplasms in the interval group were adenocarcinoma. Surgeons should consider appendiceal or colonic neoplasms in cases of complicated appendicitis when nonoperative management is considered. This is most important in patients older than 40 years, in those who forego interval appendectomy, or in those who could be lost to follow-up.

Imaging characteristics, tissue distribution, and spread of a novel oncolytic vaccinia virus carrying the human sodium iodide symporter.

INTRODUCTION: Oncolytic viruses show promise for treating cancer. However, to assess therapy and potential toxicity, a noninvasive imaging modality is needed. This study aims to determine the in vivo biodistribution, and imaging and timing characteristics of a vaccinia virus, GLV-1h153, encoding the human sodium iodide symporter (hNIS. METHODS: GLV-1h153 was modified from GLV-1h68 to encode the hNIS gene. Timing of cellular uptake of radioiodide (131)I in human pancreatic carcinoma cells PANC-1 was assessed using radiouptake assays. Viral biodistribution was determined in nude mice bearing PANC-1 xenografts, and infection in tumors confirmed histologically and optically via Green Fluorescent Protein (GFP) and bioluminescence. Timing characteristics of enhanced radiouptake in xenografts were assessed via (124)I-positron emission tomography (PET). Detection of systemic administration of virus was investigated with both (124)I-PET and 99m-technecium gamma-scintigraphy. RESULTS: GLV-1h153 successfully facilitated time-dependent intracellular uptake of (131)I in PANC-1 cells with a maximum uptake at 24 hours postinfection (P<0.05). In vivo, biodistribution profiles revealed persistence of virus in tumors 5 weeks postinjection at 10(9) plaque-forming unit (PFU)/gm tissue, with the virus mainly cleared from all other major organs. Tumor infection by GLV-1h153 was confirmed via optical imaging and histology. GLV-1h153 facilitated imaging virus replication in tumors via PET even at 8 hours post radiotracer injection, with a mean %ID/gm of 3.82 ± 0.46 (P<0.05) 2 days after intratumoral administration of virus, confirmed via tissue radiouptake assays. One week post systemic administration, GLV-1h153-infected tumors were detected via (124)I-PET and 99m-technecium-scintigraphy. CONCLUSION: GLV-1h153 is a promising oncolytic agent against pancreatic cancer with a promising biosafety profile. GLV-1h153 facilitated time-dependent hNIS-specific radiouptake in pancreatic cancer cells, facilitating detection by PET with both intratumoral and systemic administration. Therefore, GLV-1h153 is a promising candidate for the noninvasive imaging of virotherapy and warrants further study into longterm monitoring of virotherapy and potential radiocombination therapies with this treatment and imaging modality.

Irreversible electroporation is a surgical ablation technique that enhances gene transfer.

BACKGROUND: Reversible electroporation has long been used to transfer macromolecules into target cells in the laboratory by using an electric field to induce transient membrane permeability. Recently, the electric field has been modulated to produce permanent membrane permeability and cell death. This novel technique, irreversible electroporation (IRE), is being developed for nonthermal cancer ablation. We hypothesize that outside the central zone of IRE exists a peripheral zone of reversible electroporation where gene transfer may occur. METHODS: IRE of the liver was performed in a Yorkshire pig model with administration of a plasmid expressing the marker gene green fluorescent protein (GFP) by bolus or primed infusion through the hepatic artery or portal vein. After 6 hours, livers were harvested for fluorescent microscopy and histologic examination. RESULTS: Of 36 liver specimens treated with IRE and the GFP plasmid, 31 demonstrated strong green fluorescence. Liver ablation by IRE was demarcated clearly on histology. CONCLUSION: IRE is a promising technique not only for operative tissue ablation but also for gene therapy. Because IRE ablation may leave behind intact tumor antigens, these findings encourage clinical studies of tumor ablation with delivery of immunostimulatory plasmids for combined local eradication and systemic immunotherapy.

Regional liver therapy using oncolytic virus to target hepatic colorectal metastases.

The mortality of colorectal carcinoma often results from the progression of metastatic disease, which is predominantly hepatic. Although recent advances in surgical, locoregional, and systemic therapies have yielded modest improvements in survival, treatment of these aggressive lesions is limited to palliation for the vast majority of patients. Oncolytic viral therapy represents a promising novel therapeutic modality that has achieved tumor regression in several preclinical and clinical models. Evidence further suggests that locoregional viral administration may improve viral efficacy while minimizing toxicity. This study will review the theories behind hepatic arterial infusion of oncolytic virus, as well as herpes viral design, preclinical data, and clinical progress in regional liver therapy using oncolytic virus to treat hepatic colorectal carcinoma metastases.

Hyperthermia potentiates oncolytic herpes viral killing of pancreatic cancer through a heat shock protein pathway.

BACKGROUND: Oncolytic herpes simplex virus-1 (HSV-1) is designed to specifically infect, replicate in, and lyse cancer cells. This study investigates a novel therapeutic regimen, combining the effects of NV1066 (a recombinant HSV-1) and hyperthermia in the treatment of pancreatic cancer. METHODS: NV1066 is an attenuated HSV-1 that replicates in cells resistant to apoptosis. Heat shock protein 72 (Hsp72) is a member of a family of proteins that is upregulated after hyperthermic insult, lending cellular protection by inhibiting apoptosis. In these experiments, we test the hypothesis that increased Hsp72 expression in response to hyperthermia enhances anti-apoptotic mechanisms, thereby increasing viral replication and tumor cell kill. Hs 700T pancreatic cancer cells were treated with hyperthermia alone (42 degrees C), NV1066 alone, and combination therapy. Cell survival and viral growth were measured. The effect of siRNA-directed Hsp72 knockdown was also measured. RESULTS: Combining hyperthermia and viral treatment produced a synergistic effect on cell kill. Viral growth increased greater than 6-fold in the presence of hyperthermia (P < .05). Hyperthermia alone showed minimal cytotoxic activity against Hs 700T cells, while NV1066 infection resulted in approximately 50% cell kill. The combination of hyperthermia and viral infection significantly increased cell kill to approximately 80% (P < .01). Hsp72 knockdown attenuated this synergistic effect. CONCLUSION: Hyperthermia enhances NV1066 replication, thereby potentiating the viral oncolytic response against pancreatic cancer cells. This finding has potential clinical application in the use of heated perfusion or permissive hyperthermia for delivery of oncolytic viral therapies.

Is there concordance of invasive breast cancer pathologic tumor size with magnetic resonance imaging?

BACKGROUND: In the era of breast conservation therapy, preoperative imaging is imperative in planning a single definitive surgical treatment. METHODS: We performed a retrospective review of a prospectively collected database of patients treated at a single institution for invasive breast cancer over 5 years. Clinical and pathologic variables were analyzed with respect to magnetic resonance imaging (MRI) and pathologic tumor size using analysis of variance F tests and chi-square tests. RESULTS: Of 190 patients, 53% had concordance of MRI and pathologic cancer size within .5 cm. MRI overestimated 33% and underestimated 15% of tumors. Neoadjuvant chemotherapy and lymph node status were associated with discordance. Among tumors overestimated by MRI, 65% had additional significant findings in the breast tissue around the main lesion: satellite lesions, ductal carcinoma in situ, and/or lymphovascular invasion. CONCLUSIONS: Breast MRI is concordant with pathologic tumor size within .5 cm among 53% of patients. Most patients with tumors overestimated by MRI have significant findings in the surrounding breast tissue, the excision of which would be expected to benefit the patient.

Scientific Presentation Award: The impact of magnetic resonance imaging on surgical treatment of invasive breast cancer.

BACKGROUND: The purpose of this study was to examine the relationship between magnetic resonance imaging (MRI) and surgical treatment of invasive breast cancer (IBC). METHOD: The IBC patients treated from January 2003-June 2008 were reviewed by a single institution. RESULTS: A total of 814 patients were treated, out of which 562 (69%) underwent breast conservation therapy (BCT), 151 (19%) chose mastectomy alone (M), and 101 (12%) chose mastectomy with reconstruction (M+ R). The mean age was comparatively low in M + R patients (P

Does magnetic resonance imaging accurately predict residual disease in breast cancer?

BACKGROUND: The accuracy of magnetic resonance imaging (MRI) in identifying residual disease after breast conservation therapy (BCT) is unclear. METHOD: Review of an institutional database identified patients with positive or close (

Factors influencing time between biopsy and definitive surgery for malignant melanoma: do they impact clinical outcome?

BACKGROUND: Whether time between biopsy and surgery for malignant melanoma affects clinical outcomes is sparsely defined. This study evaluated factors influencing surgical interval and surgical interval effect on outcomes. METHODS: We performed a review of a prospective 10-year, single-institution database. RESULTS: There were 473 patients treated for 478 malignant melanomas. The mean surgical interval was 30.5 days. The mean thickness was 2.1 mm; 46% of patients had a surgical interval of more than 28 days whereas 8% had a surgical interval of more than 56 days. Residual melanoma was found at excision in 170 (36%) patients. Age, sex, and referral source significantly affected surgical interval, however, lesion thickness, sentinel lymph node status, ulceration, and residual melanoma at excision did not. In univariate Cox models, neither a surgical interval of 28 or less nor less than 56 days showed better overall survival (OS) or disease-free survival (DFS). In multivariate Cox models of OS and DFS including lesion thickness, sentinel lymph node status, ulceration, and residual melanoma at excision, neither a surgical interval of 28 days or fewer nor a surgical interval of 56 days or fewer significantly affected outcomes. CONCLUSIONS: Age, sex, referral source, and lesion thickness were associated with surgical interval. Immediate surgery for malignant melanoma does not significantly impact OS or DFS.

Optimal treatment of multiple ipsilateral primary breast cancers.

INTRODUCTION: The success of breast-conservation therapy (BCT) for patients with multiple ipsilateral invasive breast cancers (MIBC) is sparsely documented. METHODS: A retrospective review of single-institution experience. Patients with 2 or more invasive cancers separated by normal breast tissue were included; patients with 1 invasive cancer with additional in situ lesions and those receiving neoadjuvant therapy were excluded. RESULTS: One hundred forty-nine patients were treated over 19 years. Fifty-eight (39%) patients underwent BCT. Preoperatively, multiple tumors were suspected in more mastectomy patients than BCT patients (75% versus 62%). Most patients had 2 tumors and 1 histology. Fifty-five percent of patients with tumors within 1 quadrant underwent BCT versus 10% of patients with tumors in more than 1 quadrant. One hundred eight patients underwent sentinel lymph node (SLN) biopsy. Twenty-seven percent (34) were SLN positive. There were no regional recurrences among the SLN-negative patients. Six patients recurred: 1 nodal, 1 local, and 4 distant. The locoregional BCT recurrence rate was 3.4%. DISCUSSION: MIBC patients can safely undergo BCT with low recurrence risk. SLNB can be performed with minimal risk of regional recurrence.