First clinical application of image-guided intraoperative electron radiation therapy with real time intraoperative dose calculation in recurrent rectal cancer: technical procedure

Intraoperative radiation therapy (IORT) is a radiation technique applying a single fraction with a high dose during surgery. We report the first abdomino-pelvic application of an image-guided intraoperative electron radiation therapy with intraoperative real time dose calculation based on the individual intraoperative patient anatomy. A patient suffering from locoregionally recurrent rectal cancer after treatment with neoadjuvant re-chemoradiation was chosen for this approach. After surgical removal of the recurrence, an adequate IORT applicator was placed as usual. A novel mobile imaging device (ImagingRing, MedPhoton) was positioned around the patient covering the region to be treated with the IORT-applicator in place. It allowed the acquisition of three-dimensional intraoperative cone-beam computed tomography images suitable for dose calculation using an automated scaling (heuristic object and head scatter as well as hardening corrections) of Hounsfield units. After image acquisition confirmed the correct applicator position, the images were transferred to our treatment planning system for intraoperative dose calculation. Treatment could be accomplished using the calculated dose distribution. We herein describe the details of the procedure including necessary adjustments in the typically used IORT equipment and work flow. We further discuss the pros and cons of this new approach generally overcoming a decade long limitation of IORT procedures as well as future perspectives regarding IORT treatments.

Tumour, narrow pelvis and surgery specific factors for total mesorectal excision quality and morbidity following rectal cancer resection

BACKGROUND

Pelvic anatomy is critical in challenging rectal resections. This study investigated how pelvic anatomy relates to total mesorectal excision (TME) quality, anastomotic leakage rate, and long-term oncological outcomes.

METHODS

Patients undergoing elective rectal cancer resection from 2008 to 2017 in an Austrian institution were retrospectively reviewed regardless of the surgical approach. CT scans were analysed for pelvic measurements and volumes. The primary outcomes of interest were the correlation between pelvic dimensions and the TME quality and anastomotic leakage. Subanalysis was done by surgical approach (open, laparoscopic, transanal TME). Secondary outcomes were overall and disease-free survivals.

RESULTS

Among 154 eligible patients, 112 were included. The angle between pubic symphysis and promontory significantly correlated with worse TME grades (TME grade 1: mean(s.d.) 102.7(5.7)°; TME grade 2: 92.0(4.4)°; TME grade 3: 91.4(3.6)°; P < 0.001). A significantly lower distance between tumour and circumferential resection margin (CRM) was observed in grade 3 resections, whereas no difference appeared in grade 1 and grade 2 resection (TME grade 1: mean(s.d.) 11.92(9.4) mm; TME grade 2: 10.8(8.1) mm; TME grade 3: 3.1(4.1) mm; P = 0.003). The anastomotic leakage rate was significantly higher in case of a lower CRM (patients with anastomotic leakage: mean(s.d.) 6.8(5.8) mm versus others: 12.6(9.8) mm, P = 0.027), but not associated with pelvimetry measurements. The transanal TME (TaTME) subgroup displayed a wider angle between the pubic symphysis and promontory, younger age and improved TME quality compared to others (respectively, mean TME grades in TaTME versus open versus laparoscopic: 1.0 ± 0.0, 1.5 ± 0.7 and 1.3 ± 0.5, P = 0.013). Finally, oncological survival was not impacted by pelvic measurements or worse TME quality.

CONCLUSION

The angle between the pubic symphysis and promontory and the distance between tumour and CRM were associated with worse TME grades. The anastomotic leakage was associated with a lower CRM but not with pelvimetric measures.

The SAlzburg PEritoneal SUrface CAlculator (SAPESUCA): The First Web-Based Application for Peritoneal Surface Area Quantification

(1) Background: Peritoneal metastasized colorectal cancer is associated with a worse prognosis. The combination of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) showed promising results in selected patients, but standardization is lacking so far. We present the first tool enabling standardized peritoneal surface area (PSA) quantification in patients undergoing CRS and HIPEC: The SAlzburg PEritoneal SUrface CAlculator (SAPESUCA). (2) Methods: SAPESUCA was programmed using the R-Shiny framework. The application was validated in 23 consecutive colon cancer patients who received 27 closed oxaliplatin-based HIPECs between 2016 and 2020. The programming algorithm incorporates the patient's body surface area and its correlated peritoneal surface area (PSA) based on the 13 Peritoneal Cancer Index (PCI) regions. (3) Results: Patients' median age was 56 years. Median PCI was 9. SAPESUCA revealed a mean PSA of 18,613 cm² ± 1951 of all patients before compared to 13,681 cm² ± 2866 after CRS. The Central PCI region revealed the highest mean peritonectomy extent (1517 cm² ± 737). The peritonectomy extent correlated significantly with PCI score and postoperative morbidity. The simulated mean oxaliplatin dose differed significantly before and after CRS (558 mg/m² ± 58.4 vs. 409 mg/m² ± 86.1; p < 0.0001). (4) Conclusion: SAPESUCA is the first free web-based app for standardized determination of the resected and remaining PSA after CRS. The tool enables chemotherapeutic dose adjustment to the remaining PSA.

Sarcopenic Obesity Is a Risk Factor for Worse Oncological Long-Term Outcome in Locally Advanced Rectal Cancer Patients: A Retrospective Single-Center Cohort Study

BACKGROUND

Malnutrition and skeletal muscle waste (sarcopenia) are known as predictive factors for a poor postoperative outcome. Paradoxically, obesity seems to be associated with a survival advantage in wasting diseases such as cancer. Thus, the interpretation of body composition indices and their impact on rectal cancer therapy has become more and more complex. The aim of this study was to evaluate body composition indices in locally advanced rectal cancer patients prior to therapy and their impact on short- and long-term outcomes.

METHODS

Between 2008 and 2018, 96 patients were included in this study. Pre-therapeutic CT scans were used to evaluate visceral and subcutaneous fat mass, as well as muscle mass. Body composition indices were compared to body mass index, morbidity, anastomotic leakage rate, local recurrency rate, and oncological long-term outcomes.

RESULTS

Increased visceral fat (p < 0.01), subcutaneous fat (p < 0.01), and total fat mass (p = 0.001) were associated with overweight. Skeletal muscle waste (sarcopenia) (p = 0.045), age (p = 0.004), comorbidities (p < 0.01), and sarcopenic obesity (p = 0.02) were significantly associated with increased overall morbidity. The anastomotic leakage rate was significantly influenced when comorbidities were present (p = 0.006). Patients with sarcopenic obesity showed significantly worse disease-free (p = 0.04) and overall survival (p = 0.0019). The local recurrency rate was not influenced by body composition indices.

CONCLUSION

Muscle waste, older age, and comorbidities were demonstrated as strong risk factors for increased overall morbidity. Sarcopenic obesity was associated with worse DFS and OS. This study underlines the role of nutrition and appropriate physical activity prior to therapy.

How We Treat Localized Rectal Cancer-An Institutional Paradigm for Total Neoadjuvant Therapy

Total neoadjuvant therapy (TNT)-the neoadjuvant employment of radiotherapy (RT) or chemoradiation (CRT) as well as chemotherapy (CHT) before surgery-may lead to increased pathological complete response (pCR) rates as well as a reduction in the risk of distant metastases in locally advanced rectal cancer. Furthermore, increased response rates may allow organ-sparing strategies in a growing number of patients with low rectal cancer and upfront immunotherapy has shown very promising early results in patients with microsatellite instability (MSI)-high/mismatch-repair-deficient (dMMR) tumors. Despite the lack of a generally accepted treatment standard, we strongly believe that existing data is sufficient to adopt the concept of TNT and immunotherapy in clinical practice. The treatment algorithm presented in the following is based on our interpretation of the current data and should serve as a practical guide for treating physicians-without any claim to general validity.

Are risk factors for anastomotic leakage influencing long-term oncological outcomes after low anterior resection of locally advanced rectal cancer with neoadjuvant therapy? A single-centre cohort study

PURPOSE

Anastomotic leakage (AL) poses the most serious problem following low anterior resection in patients with rectal cancer independent of surgical approach or technique. The aim of this study was to evaluate risk factors for the occurrence of AL and how they affect the oncological long-term outcome of patients who received neoadjuvant therapy.

METHODS

A single centre cohort study of 163 consecutive locally advanced rectal cancer patients (cT3, cT4, N +) that received neoadjuvant therapy followed by resection with primary anastomosis between January 1998 and December 2020 were included in this study. Short- and long-term findings were compared between patients with AL (Leakage +) and without AL (Leakage -).

RESULTS

A complete follow-up was obtained from 163 patients; thereby, 33 patients (20%) developed an AL. We observed more patients with comorbidities (38% vs. 61%, p = 0.049) which developed a leakage in the course. Permanent stoma rate (36% vs. 18%, p = 0.03) was higher, and time between primary operation and stoma reversal was longer (219 days [172-309] vs. 93 days [50-182], p < 0.001) in this leakage group as well. Tumour distance lower than 6 cm from the anal verge (OR: 2.81 [95%CI: 1.08-7.29], p = 0.04) and comorbidities (OR: 2.22 [95%CI: 1.01-4.90], p = 0.049) was evaluated to be independent risk factors for developing an AL after rectal cancer surgery. Oncological outcome was not influenced by AL nor by other associated risk factors.

CONCLUSION

We could clearly detect the distance of tumour from the anal verge and comorbidities independent risk factors for the occurrence of AL. Oncological findings and long-term outcome were not influenced by these particular risk factors.

Is Robotic Assisted Colorectal Cancer Surgery Equivalent Compared to Laparoscopic Procedures during the Introduction of a Robotic Program? A Propensity-Score Matched Analysis

Simple Summary

The introduction of a robotic program is challenging and requires extensive experience in minimally invasive surgery. Short-term outcomes and oncological quality should not differ between robotic and laparoscopic surgery. To our knowledge, no data on the quality of surgery at the time of introduction of the robotic platform are available. The aim of this study was to compare short-term outcomes and oncological findings of robotic-assisted colorectal resections with those of conventional laparoscopic surgery within the first three years after the introduction of the robotic platform.

Abstract

Background: Robotic surgery represents a novel approach for the treatment of colorectal cancers and has been established as an important and effective method over the last years. The aim of this work was to evaluate the effect of a robotic program on oncological findings compared to conventional laparoscopic surgery within the first three years after the introduction. Methods: All colorectal cancer patients from two centers that either received robotic-assisted or conventional laparoscopic surgery were included in a comparative study. A propensity-score-matched analysis was used to reduce confounding differences. Results: A laparoscopic resection (LR Group) was performed in 82 cases, and 93 patients were treated robotic-assisted surgery (RR Group). Patients’ characteristics did not differ between groups. In right-sided resections, an intracorporeal anastomosis was significantly more often performed in the RR Group (LR Group: 5 (26.31%) vs. RR Group: 10 (76.92%), p = 0.008). Operative time was shown to be significantly shorter in the LR Group (LR Group: 200 min (150–243) vs. 204 min (174–278), p = 0.045). Conversions to open surgery did occur more often in the LR Group (LR Group: 16 (19.51%) vs. RR Group: 5 (5.38%), p = 0.004). Postoperative morbidity, the number of harvested lymph nodes, quality of resection and postoperative tumor stage did not differ between groups. Conclusion: In this study, we could clearly demonstrate robotic-assisted colorectal cancer surgery as effective, feasible and safe regarding postoperative morbidity and oncological findings compared to conventional laparoscopy during the introduction of a robotic system.

Short- and Long-Term Outcome of Laparoscopic- versus Robotic-Assisted Right Colectomy: A Systematic Review and Meta-Analysis

Background: There is a rapidly growing literature available on right hemicolectomy comparing the short- and long-term outcomes of robotic right colectomy (RRC) to that of laparoscopic right colectomy (LRC). The aim of this meta-analysis is to revise current comparative literature systematically. Methods: A systematic review of comparative studies published between 2000 to 2021 in PubMed, Scopus and Embase was performed. The primary endpoint was postoperative morbidity, mortality and long-term oncological results. Secondary endpoints consist of blood loss, conversion rates, complications, time to first flatus, hospital stay and incisional hernia rate. Results: 25 of 322 studies were considered for data extraction. A total of 16,099 individual patients who underwent RRC (n = 1842) or LRC (n = 14,257) between 2002 and 2020 were identified. Operative time was significantly shorter in the LRC group (LRC 165.31 min ± 43.08 vs. RRC 207.38 min ± 189.13, MD: −42.01 (95% CI: −51.06−32.96), p < 0.001). Blood loss was significantly lower in the RRC group (LRC 63.57 ± 35.21 vs. RRC 53.62 ± 34.02, MD: 10.03 (95% CI: 1.61−18.45), p = 0.02) as well as conversion rate (LRC 1155/11,629 vs. RRC 94/1534, OR: 1.65 (1.28−2.13), p < 0.001) and hospital stay (LRC 6.15 ± 31.77 vs. RRC 5.31 ± 1.65, MD: 0.84 (95% CI: 0.29−1.38), p = 0.003). Oncological long-term results did not differ between both groups. Conclusion: The advantages of robotic colorectal procedures were clearly demonstrated. RRC can be regarded as safe and feasible. Most of the included studies were retrospective with a limited level of evidence. Further randomized trials would be suitable.

Prolonged Exposure to Oxaliplatin during HIPEC Improves Effectiveness in a Preclinical Micrometastasis Model

Simple Summary

Absence of survival benefits when adding hyperthermic intraperitoneal chemotherapy (HIPEC) with oxaliplatin to cytoreductive surgery in peritoneal metastasis from colorectal cancer has recently been shown in the randomized controlled PRODIGE 7 trial. We therefore aimed to investigate the effects of this treatment modality in a preclinical micrometastasis model. Cancer cells were incubated with either patient samples obtained during HIPEC procedures or with defined oxaliplatin-containing solutions prepared according to clinically established HIPEC protocols. Our results demonstrate a limited effectiveness of short-term HIPEC in simulations with oxaliplatin to eliminate micrometastases, although we used platinum-sensitive cell lines for our model. Since these results are in line with findings from current research, our studies might offer further convincing evidence and potential explanations for HIPEC futility observed in clinical application.

Abstract

Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (HIPEC) was considered a promising treatment for patients with peritoneal metastasis from colorectal cancer. However, the recently published randomized controlled PRODIGE 7 trial failed to demonstrate survival benefits through the addition of short-term oxaliplatin-based HIPEC. Constituting a complex multifactorial treatment, we investigated HIPEC in a preclinical model concerning the elimination of minimal tumor residues, thereby aiming to better understand the size of effects and respective clinical trial results. Patient samples of peritoneal perfusates obtained during HIPEC treatments and oxaliplatin-containing solutions at clinically relevant dosages, conforming with established HIPEC protocols, were assessed regarding their ability to eliminate modelled ~100 µm thickness cancer cell layers. Impedance-based real-time cell analysis and classical end-point assays were used. Flow cytometry was employed to determine the effect of different HIPEC drug solvents on tumor cell properties. Effectiveness of peritoneal perfusate patient samples and defined oxaliplatin-containing solutions proved limited but reproducible. HIPEC simulations for 30 min reduced the normalized cell index below 50% with peritoneal perfusates from merely 3 out of 9 patients within 72 h, indicating full-thickness cytotoxic effects. Instead, prolonging HIPEC to 1 h enhanced these effects and comprised 7 patients’ samples, while continuous drug exposure invariably resulted in complete cell death. Further, frequently used drug diluents caused approximately 25% cell size reduction within 30 min. Prolonging oxaliplatin exposure improved effectiveness of HIPEC to eliminate micrometastases in our preclinical model. Accordingly, insufficient penetration depth, short exposure time, and the physicochemical impact of drug solvents may constitute critical factors.

Incidence and risk factors for umbilical incisional hernia after reduced port colorectal surgery (SIL + 1 additional port)-is an umbilical midline approach really a problem?

PURPOSE

Umbilical midline incisions for single incision- or reduced port laparoscopic surgery are still discussed controversially because of a higher rate of incisional hernia compared to conventional laparoscopic techniques. The aim of this study was to evaluate incidence and risk factors for incisional hernia after reduced port colorectal surgery.

METHODS

A total 241 patients underwent elective reduced port colorectal surgery between 2014 and 2020. Follow-up was achieved through telephone interview or clinical examination. The study collective was examined using univariate and multivariate analysis.

RESULTS

A total of 150 patients with complete follow-up were included into this study. Mean follow-up time was 36 (IQR 24-50) months. The study collective consists of 77 (51.3%) female and 73 (48.7%) male patients with an average BMI of 26 kg/m² (IQR 23-28) and an average age of 61 (± 14). Indication for surgery was diverticulitis in 55 (36.6%) cases, colorectal cancer in 65 (43.3%) patients, and other benign reasons in 30 (20.0%) cases. An incisional hernia was observed 9 times (6.0%). Obesity (OR 5.8, 95% CI 1.5-23.1, p = 0.02) and pre-existent umbilical hernia (OR 161.0, 95% CI 23.1-1124.5, p < 0.01) were significant risk factors for incisional hernia in the univariate analysis. Furthermore, pre-existent hernia is shown to be a risk factor also in multivariate analysis.

CONCLUSION

We could demonstrate that reduced port colorectal surgery using an umbilical single port access is feasible and safe with a low rate of incisional hernia. Obesity and pre-existing umbilical hernia are significant risk factors for incisional hernia.

Case Report: Adult Right-Sided Bochdalek Hernia Complicated by Intrathoracic Bowel Perforation

Right-sided Bochdalek hernia is a mostly congenital condition of the diaphragm caused by a persistence of the pleuroperitoneal cavity and a rare disease in adults. As it often presents as an emergent situation, urgent diagnostics and surgical intervention are essential to reduce morbidity and mortality rates. Choosing the right surgical approach (abdominal, thoracic, or a combination of both) can be very challenging for clinicians. Here, we report a case of a 40-year-old woman, who presented with severe abdominal pain and tachypnoea. Imaging revealed a right-sided Bochdalek hernia. Emergency laparotomy was performed followed by reduction of hernia content, right-sided hemicolectomy, and side-to-side anastomosis from the ileum to the transverse colon due to intestinal ischemia and intrathoracic bowel perforation. The post-operative course was complicated by a pleural empyema. Therefore, the patient underwent thoracotomy. One year after surgical repair the patient had no recurrence. Here, we discuss feasible approaches for the surgical management of complicated Bochdalek hernias.

HDAC Screening Identifies the HDAC Class I Inhibitor Romidepsin as a Promising Epigenetic Drug for Biliary Tract Cancer

Simple Summary

Biliary tract cancer (BTC) is a rare disease with dismal outcomes. Therefore, the investigation of new therapeutic targets is urgently required. In this study, we demonstrate that histone deacetylases (HDACs) are expressed in BTC cell lines and that treatment of BTC cells with different HDAC class inhibitors reduces cell viability. Specifically, we found that BTC cells are vulnerable to the HDAC class I inhibitor romidepsin. Treatment with romidepsin resulted in apoptotic cell death of BTC cells and reduced HDAC activity. Furthermore, romidepsin augmented the cytotoxic effect of the standard chemotherapeutic cisplatin. HDAC class I proteins were also expressed in BTC patient samples. We detected that BTC patients with high HDAC-2-expressing tumors showed a significantly shorter survival. In summary, we were able to demonstrate that BTC cells are vulnerable to HDAC inhibition and that the HDAC class I inhibitor romidepsin might be a promising anti-BTC substance.

Abstract

Inhibition of histone deacetylases (HDACs) is a promising anti-cancer approach. For biliary tract cancer (BTC), only limited therapeutic options are currently available. Therefore, we performed a comprehensive investigation of HDAC expression and pharmacological HDAC inhibition into a panel of eight established BTC cell lines. The screening results indicate a heterogeneous expression of HDACs across the studied cell lines. We next tested the effect of six established HDAC inhibitors (HDACi) covering pan- and class-specific HDACis on cell viability of BTC cells and found that the effect (i) is dose- and cell-line-dependent, (ii) does not correlate with HDAC isoform expression, and (iii) is most pronounced for romidepsin (a class I HDACi), showing the highest reduction in cell viability with IC₅₀ values in the low-nM range. Further analyses demonstrated that romidepsin induces apoptosis in BTC cells, reduces HDAC activity, and increases acetylation of histone 3 lysine 9 (H3K9Ac). Similar to BTC cell lines, HDAC 1/2 proteins were heterogeneously expressed in a cohort of resected BTC specimens (n = 78), and their expression increased with tumor grading. The survival of BTC patients with high HDAC-2-expressing tumors was significantly shorter. In conclusion, HDAC class I inhibition in BTC cells by romidepsin is highly effective in vitro and encourages further in vivo evaluation in BTC. In situ assessment of HDAC 2 expression in BTC specimens indicates its importance for oncogenesis and/or progression of BTC as well as for the prognosis of BTC patients.

Impact of PD-L1 Scores and Changes on Clinical Outcome in Rectal Cancer Patients Undergoing Neoadjuvant Chemoradiotherapy

Reports on the prognostic role of programmed death-ligand 1 (PD-L1) expression in rectal cancer are controversial. We investigated expression patterns and changes of PD-L1 in rectal cancer patients undergoing neoadjuvant chemoradiotherapy (CRT). Seventy-two patients diagnosed with rectal cancer and/or treated with fluorouracil-based neoadjuvant CRT at the Department of Internal Medicine III of the Paracelsus Medical University Salzburg (Austria) between January 2003 and October 2012 were included. PD-L1 scoring was performed according to the tumor proportion score (TPS), combined positive score (CPS), and immune cell score (IC). PD-L1 TPS prior to neoadjuvant CRT had a statistically significant impact on survival (median: ≤1%: 95.4 months (95% CI: 51.8-not reached) vs. >1%: not reached, p = 0.03, log-rank). Patients with a PD-L1 TPS ≤1% prior to and after CRT showed an inferior survival compared to all other patients (median: 56.7 months (95% CI: 51.4-not reached) vs. not reached, p = 0.005, log-rank). In multivariate analysis, PD-L1 TPS prior to neoadjuvant CRT (>1% vs. ≤1%, hazard ratio: 0.29 (95% CI: 0.11-0.76), p = 0.01) remained independently associated with survival. In conclusion, low PD-L1 TPS was associated with inferior survival in rectal cancer patients undergoing neoadjuvant CRT. A prospective validation of the prognostic value of PD-L1 expression in rectal cancer patients within a clinical trial is necessitated.

Hot Spot TERT Promoter Mutations Are Rare in Sporadic Pancreatic Neuroendocrine Neoplasms and Associated with Telomere Length and Epigenetic Expression Patterns

Cancer cells activate a telomere maintenance mechanism like telomerase in order to proliferate indefinitely. Telomerase can be reactivated by gain-of-function Telomerase Reverse Transcriptase (TERT) promoter mutations (TPMs) that occur in several cancer subtypes with high incidence and association with diagnosis, prognosis and epigenetics. However, such information about TPMs in sporadic pancreatic neuroendocrine neoplasms (pNENs) including tumor (pNET) and carcinoma (pNEC) is less well defined. We have studied two hot spot TPMs and telomere length (TL) in pNEN and compared the results with clinicopathological information and proliferation-associated miRNA/HDAC expression profiles. DNA was isolated from formalin-fixed paraffin-embedded (FFPE) tissue of 58 sporadic pNEN patients. T allele frequency of C250T and C228T TPM was analyzed by pyrosequencing, relative TL as telomeric content by qPCR. In total, five pNEN cases (9%) including four pNETs and one pNEC were identified with TPMs, four cases with exclusive C250T as predominant TPM and one case with both C250T and C228T. T allele frequencies of DNA isolated from adjacent high tumor cell content FFPE tissue varied considerably, which may indicate TPM tumor heterogeneity. Overall and disease-free survival was not associated with TPM versus wild-type pNEN cases. Binary category analyses indicated a marginally significant relationship between TPM status and longer telomeres (p = 0.086), and changes in expression of miR449a (p = 0.157), HDAC4 (p = 0.146) and HDAC9 (p = 0.149). Future studies with larger patient cohorts are needed to assess the true clinical value of these rare mutations in pNEN.

The PEritoneal SUrface CAlculator (PESUCA): A new tool to quantify the resected peritoneal surface area after cytoreductive surgery

BACKGROUND

The body surface area (BSA) is taken as a measure for the effective contact area for dosing in hyperthermic intraperitoneal chemotherapy (HIPEC). Currently, the pharmacokinetic effect of the reduced peritoneal surface area (PSA) after cytoreductive surgery (CRS) during HIPEC remains unclear. Here a proprietary software solution (PEritoneal SUrface CAlculator (PESUCA)) to quantify the resected PSA in patients with peritoneal surface malignancies (PSM) undergoing CRS and HIPEC is presented.

METHODS

The PESUCA tool was programmed as a desktop and online software solution. The applicability was evaluated in 36 patients. The programming-algorithm is briefly summarized as follows: (1) calculation of BSA, (2) correlation to PSA, (3) calculation of the relative proportion of 40 different anatomical regions to total PSA before CRS, (4) instantaneous input of each resected proportion in the 40 anatomical regions during CRS, and (5) determination of the resected and remaining PSA after CRS.

RESULTS

The proof of concept revealed a mean PSA of all patients before CRS of 18,741 ± 321 cm2 compared to 13,611 ± 485 cm2 after CRS (p<0.0001). Patients' supramesocolic and inframesocolic visceral and parietal peritoneal area before and after CRS procedure were quantitatively determined.

CONCLUSIONS

Here the first tool that enables detailed PSA quantification in patients with PSM undergoing CRS is presented. This makes the software a valuable contribution to ensue more accurate assessment and improved comparability of peritoneal disease extent. Furthermore, after external validation, PESUCA could be the basis for dose adjustment of intraperitoneal chemotherapy regimens based on the remaining PSA after CRS.

Surgical and radiological behavior of MRI-depictable mesh implants after TAPP repair: the IRONMAN study

PURPOSE

Knowledge of postoperative behavior of mesh implants used for hernia repair is generally limited to cases of recurrence, local complications or return to the previous operative field in other pathological conditions. Previous studies with MRI-visible mesh implants in different parts of the abdominal wall have led to variable findings with regard to mesh properties and mostly described a reduction in size over time with subsequently limited mesh overlap over hernia defects which could contribute to recurrence. We aimed to evaluate implant properties in a mechanically stable anatomical region after TAPP repair of primary unilateral inguinal hernias in men with clinical and MRI examinations 4 weeks and 1 year after surgery.

METHODS

From 11/2015 to 01/2019, 23 men with primary, unilateral, inguinal hernias underwent TAPP repair with iron particle-loaded, MRI-visible mesh implants in a prospective cohort study. In 16 patients the operative outcome could be evaluated 4 weeks and 12 months after surgery by clinical examination and MRI evaluation with regard to postoperative course, possible adverse outcomes and radiological findings related to implant behavior-namely MRI-identifiability, mesh dislocation or reduction in surface area.

RESULTS

All included patients had an uneventful postoperative clinical course. MRI after 4 weeks revealed one postoperative seroma, which resolved spontaneously. No recurrence was detected. Mesh implants could be accurately delineated in DIXON-IN studies and showed neither clinically nor statistically significant changes in size or position.

CONCLUSION

4 weeks and 1 year after a standardized TAPP procedure the mesh implant used in this study showed no tendency towards dislocation or reduction in size in this anatomical position. Its MRI visibility allows accurate delineation during the postoperative course by experienced radiologists in appropriate MRI protocols. Larger patient series are desirable to further support these findings. Shrinkage of implants in the groin as a reason for early recurrence may be overestimated.

Reproducibility of the peritoneal regression grading score for assessment of response to therapy in peritoneal metastasis

AIMS

The four-tiered peritoneal regression grading score (PRGS) assesses the response to chemotherapy in peritoneal metastasis (PM). The PRGS is used, for example, to assess the response to pressurised intraperitoneal aerosol chemotherapy (PIPAC). However, the reproducibility of the PRGS is currently unknown. We aimed to evaluate the inter- and intraobserver variability of the PRGS.

METHODS AND RESULTS

Thirty-three patients who underwent at least three PIPAC treatments as part of the PIPAC-OPC1 or PIPAC-OPC2 clinical trials at Odense University Hospital, Denmark, were included. Prior to each therapy cycle, peritoneal quadrant biopsies were obtained and three haematoxylin and eosin (H&E)-stained step sections were scanned and uploaded to a pseudonymised web library. For determining interobserver variability, eight pathologists assessed the PRGS for each quadrant biopsy, and Krippendorff's alpha and intraclass correlation coefficients (ICCs) were calculated. For determining intraobserver variability, three pathologists repeated their own assessments and Cohen's kappa and ICCs were calculated. A total of 331 peritoneal biopsies were analysed. Interobserver variability for PRGS of each biopsy and for the mean and maximum PRGS per biopsy set was moderate to good/substantial. The intraobserver variability for PRGS of each biopsy and for the mean and maximum PRGS per biopsy set was good to excellent/almost perfect.

CONCLUSIONS

Our data support the PRGS as a reproducible and useful tool to assess response to intraperitoneal chemotherapy in PM. Future studies should evaluate the prognostic and predictive role of the PRGS.

Pharmacological Inhibition of Class IIA HDACs by LMK-235 in Pancreatic Neuroendocrine Tumor Cells

Histone deacetylases (HDACs) play a key role in epigenetic mechanisms in health and disease and their dysfunction is implied in several cancer entities. Analysis of expression patterns in pancreatic neuroendocrine tumors (pNETs) indicated HDAC5 to be a potential target for future therapies. As a first step towards a possible treatment, the aim of this study was to evaluate the in vitro cellular and molecular effects of HDAC5 inhibition in pNET cells. Two pNET cell lines, BON-1 and QGP-1, were incubated with different concentrations of the selective class IIA HDAC inhibitor, LMK-235. Effects on cell viability were determined using the resazurin-assay, the caspase-assay, and Annexin-V staining. Western Blot and immunofluorescence microscopy were performed to assess the effects on HDAC5 functionality. LMK-235 lowered overall cell viability by inducing apoptosis in a dose- and time-dependent manner. Furthermore, acetylation of histone-H3 increased with higher LMK-235 concentrations, indicating functional inhibition of HDAC4/5. Immunocytochemical analysis showed that proliferative activity (phosphohistone H3 and Ki-67) decreased at highest concentrations of LMK-235 while chromogranin and somatostatin receptor 2 (SSTR2) expression increased in a dose-dependent manner. HDAC5 expression was found to be largely unaffected by LMK-235. These findings indicate LMK-235 to be a potential therapeutic approach for the development of an effective and selective pNET treatment.

HDAC-Linked "Proliferative" miRNA Expression Pattern in Pancreatic Neuroendocrine Tumors

Epigenetic factors are essentially involved in carcinogenesis, tumor promotion, and chemoresistance. Two epigenetic key players are miRNAs and histone deacetylases (HDACs). As previously shown by own theoretical databank analysis, the crosstalk between miRNAs and HDACs is relevant in different human chronic diseases and cancerogenic pathways. We aimed to investigate a potential connection between the expression of a well-defined subset of "proliferation-associated" miRNAs and the expression of HDACs as well as clinical parameters in pancreatic neuroendocrine tumors (pNETs).

MATERIALS AND METHODS

Expression levels of miRNA132-3p, miRNA145-5p, miRNA183-5p, miRNA34a-5p, and miRNA449a in 57 pNETs resected between 1997 and 2015 were measured and linked to the immunohistochemical expression pattern of members of the four HDAC classes on human tissue microarrays. All pNET cases were clinically and pathologically characterized according to published guidelines. Correlation analysis revealed a significant association between expression of specific miRNAs and two members of the HDAC family (HDAC3 and HDAC4). Additionally, a linkage between miRNA expression and clinico-pathological parameters like grading, TNM-staging, and hormone activity was found. Moreover, overall and disease-free survival is statistically correlated with the expression of the investigated miRNAs. Overall, we demonstrated that specific miRNAs could be linked to HDAC expression in pNETs. Especially miRNA449a (associated with HDAC3/4) seems to play an important role in pNET proliferation and could be a potential prognostic factor for poor survival. These first data could help, to improve our knowledge of the complex interactions of the epigenetic drivers in pNETs for further therapeutic approaches.

Thermographic real-time-monitoring of surgical radiofrequency and microwave ablation in a perfused porcine liver model

Radiofrequency ablation (RFA) and microwave ablation (MWA) are currently the dominant modalities to treat unresectable liver tumors. Monitoring the ablation process with b-mode-sonography is often hampered by artefacts. Furthermore, vessels may cause cooling in the adjacent tumor target (heat-sink-effect) with risk of local recurrence. The present study evaluated infrared-thermography to monitor surgical RFA/MWA and detect heat-sink-effects in real-time. RFA and MWA of perfused porcine livers was conducted at peripheral and central-vessel-adjacent locations, and monitored by real-time thermography. Ablation was measured and evaluated by gross pathology. The mean time for ablation was significantly longer in RFA compared with MWA (8 vs. 2 min). Although mean macroscopic ablation diameter was similar (RFA, 3.17 cm; MWA, 3.38 cm), RFA showed a significant heat-sink-effect compared with MWA. The surface temperature during central RFA near vessels was 1/3 lower compared with peripheral RFA (47.11±8.35°C vs. 68.72±12.70°C; P<0.001). There was no significant difference in MWA (50.52±8.35°C vs. 50.18±10.35°C; P=0.74). In conclusion, thermography is suitable to monitor the correct ablation with MWA and RFA. The results of the current study demonstrated a significant heat-sink-effect for RFA, but not MWA near vessels. MWA reaches consistent surface temperatures much faster than RFA. With further in vivo validation, thermography may be useful to ensure appropriate ablation particularly near vulnerable or vascular structures.

Comprehensive immunohistochemical analysis of histone deacetylases in pancreatic neuroendocrine tumors: HDAC5 as a predictor of poor clinical outcome

Epigenetic factors contribute to carcinogenesis, tumor promotion, and chemoresistance. Histone deacetylases (HDACs) are epigenetic regulators that primarily cause chromatin compaction, leading to inaccessibility of promoter regions and eventually gene silencing. Many cancer entities feature overexpression of HDACs. Currently, the role of HDACs in pancreatic neuroendocrine tumors (pNETs) is unclear. We analyzed the expression patterns of all HDAC classes (classes I, IIA, IIB, III, and IV) in 5 human tissue microarrays representing 57 pNETs resected between 1997 and 2013 and corresponding control tissue. All pNET cases were characterized clinically and pathologically according to recent staging guidelines. The investigated cases included 32 (56.1%) female and 25 (43.9%) male pNET patients (total n=57, 47.4% immunohistochemically endocrine positive). Immunohistochemical profiling revealed a significant up-regulation of all HDAC classes in pNET versus control, with different levels of intensity and extensity ranging from 1.5- to >7-fold up-regulation. In addition, expression of several HDACs (HDAC1, HDAC2, HDAC5, HDAC11, and Sirt1) was significantly increased in G3 tumors. Correlation analysis showed a significant association between the protein expression of HDAC classes I, III, and IV and rate of the pHH3/Ki-67-associated mitotic and proliferation index. Furthermore, especially HDAC5 proved as a negative predictor of disease-free and overall survival in pNET patients. Overall, we demonstrate that specific members of all 4 HDAC classes are heterogeneously expressed in pNET. Moreover, expression of HDACs was associated with tumor grading, proliferation markers, and patient survival, therefore representing interesting new targets in pNET treatment.

First Episode of Spontaneous Pneumothorax: CT-based Scoring to Select Patients for Early Surgery

BACKGROUND

Although recurrence of primary spontaneous pneumothorax (PSP) is frequent, guidelines do not routinely recommend surgery after first presentation. A CT-based lung dystrophy severity score (DSS) has recently been proposed to predict recurrence following conservative therapy. This study compares the DSS in surgically and conservatively treated patients.

METHODS

This is a retrospective analysis of first episode PSP patients, comparing video-assisted thoracic surgery (VATS; group A) to conservative treatment with or without chest drainage (group B). CT scans were reviewed for blebs or bullae, and patients were assigned DSS values and stratified into risk groups (low and high-grade). Primary end point was ipsilateral or contralateral recurrence.

RESULTS

Fifty-six patients were included, 33 received VATS and 23 conservative treatment. In total, 37.5 % experienced recurrence, with a 5-year estimated recurrence rate of 40.7 % (group A: 13.3 %; group B: 73.9 %; p < 0.001). In group B, detection of any dystrophic lesions resulted in significantly higher 5-year recurrence rates (86.7 vs. 50.0 %; p = 0.03), there was no significant difference in group A (17.7 vs. 7.7 %; p = 0.50). Greater DSS values correlated with higher 5-year recurrence rates in group B (p = 0.02), but not in group A (p = 0.90). Comparing low- and high-grade patients in group B resulted in a significant 5-year recurrence rate of 53.8 versus 100 % (p = 0.023).

CONCLUSIONS

The DSS is useful to indicate VATS after the first episode. For routine application, assigning patients to low- and high-grade groups seems most practical. We recommend CT-evaluation for every PSP patient and early surgery for those with lesions exceeding one bleb. After VATS, the preoperative DSS is not beneficial in predicting recurrence.

Back to the start: Evaluation of prognostic markers in gastrointestinal stromal tumors

The aim of this study was to provide a standardized risk stratification model for gastrointestinal stromal tumors (GISTs) based on tumor localization, tumor size, involved lymph nodes and metastases, as well as mitotic activity and other morphological and molecular markers, in order to improve the risk evaluation scheme for recurrence, metastatic spread and survival for patients with GIST. A total of 201 cases of patients with GIST were investigated according to standardized morphological markers, including nuclear pleomorphism, tumor cell necrosis, mucosal infiltration, ulceration, skeinoid fibers and growth pattern. In addition, all cases were immunohistochemically analyzed using a tissue microarray platform for various markers of differentiation (CD34, CD44, CD117, desmin, discovered on GIST 1, platelet-derived growth factor receptor α, S-100 and smooth muscle actin) and proliferation (B-cell lymphoma 2, P16, P53, phosphohistone H3 and Ki-67). These findings were correlated by uni- and multivariable analyses with clinicopathological characteristics, including recurrence, metastasis and survival. The general clinicopathological parameters of this GIST specimen cohort were comparable to previous studies. While several parameters exhibited clear associations to each other and to the defined clinical endpoints, the multivariate analysis reduced the number of relevant prognostic variables to localization, margin status, growth pattern and hematoxylin and eosin-based mitosis/Ki-67-based proliferation of GISTs. With the exception of CD34, none of the applied markers of differentiation and proliferation were found to be independent prognostic markers in GIST and the classical risk factors of GIST remain important prognostic factors. Additionally, growth pattern may predict the risk of recurrence and metastasis in GIST patients. Additional independent molecular prognostic markers remain to be identified and validated.

Abstract P4-14-11: Efficacy and cardiac safety in neoadjuvant treatment of Her2 positive breast cancer with concomitant nonpegylated liposomal doxorubicin, docetaxel and dual blockade with trastuzumab and pertuzumab: A retrospective analysis

Background: Approval to pertuzumab as part of a complete treatment regimen for patients with early stage breast cancer (EBC) before surgery (neoadjuvant setting) was granted by the FDA in September 2013. Since then, the relevance of neoadjuvant treatment in Her2 overexpressing breast cancer has increased considerably. This for instance has been emphasized by the results of the Neosphere Study, in which dual blockade of Her2 was combined with docetaxel as chemotherapy backbone and resulted in favorable pCR rates.

But it is likely, that anthracyclines could play an important role in enhancing the effectiveness of the above mentioned treatment. However, there is only little data about the cardiac safety of this combination. The use of liposomal doxorubicin might be a valuable alternative with low cardiotoxicity, as it has been shown in comparable publications without the use of pertuzumab. Therefore we report pCR-rate and cardiac safety of a single arm, retrospective, multicenter analysis of neoadjuvant treatment for Her2 positive EBC with liposomal doxorubicin, docetaxel, trastuzumab and pertuzumab.

Methods: In this study 42 women with Her2 positive EBC were investigated in 4 oncological departments in Austria. 41 patients were treated with liposomal doxorubicin (50 mg/m2), docetaxel (75 mg/m2) concurrent with trastuzumab and pertuzumab in standard dosage for 6 cycles as neoadjuvant therapy. One patient refused to receive a chemotherapy but agreed to be treated with combined antibody therapy alone. All patients were free of cardiovascular disease and had a left ventricular ejection fraction (LVEF) of ≥ 50%. Cardiac function was measured by LVEF and was examined at regular intervals (cycles 0-3, cycle 6, FU). Clinical response was evaluated by diagnostic breast imaging after cycles 3 and 6. All patients underwent surgery after neoadjuvant chemotherapy. The absence of any residual invasive cancer in the breast and axilla was defined as pathological complete response (pCR). Median follow up was 1.3 years.

Results: Median age of the patients was 49 years. After 6 cycles of treatment the pCR rate was 76.2%. In this cohort a negative estrogen-and/or progesteron receptor was predictive for pCR (p&lt;0.001). These patients achieved pCR in 95.2%. The antibody only treatment in one case also resulted in a pCR. No patient progressed during treatment. Only one of the patients (2,4%) suffered symptomatic heart failure after surgery. The patient initially presented with an LVEF of 16%.

Conclusions: In this multicenter analysis we observed a considerably high rate of pCR in HER2-positive EBC treated with liposomal doxorubicin, docetaxel, trastuzumab and pertuzumab. Especially the group of hormone receptor negative patients showed a remarkable response rate. The addition of liposomal doxorubicin entails a very favorable cardiotoxicity profile. This regimen is a safe treatment option in patients with HER-2 positive breast cancer.

Citation Format: Egle D, Hubalek M, Hager C, Poyßl C, Lang A, Jäger T, Volgger B, Abdel-Azim S, Tiechl J, Angerer J, Marth C. Efficacy and cardiac safety in neoadjuvant treatment of Her2 positive breast cancer with concomitant nonpegylated liposomal doxorubicin, docetaxel and dual blockade with trastuzumab and pertuzumab: A retrospective analysis. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-14-11.

Abstract P1-13-10: Capecitabine in combination with bendamustine in pretreated women with HER2-negative metastatic breast cancer: Stage 1 results of a phase II trial (AGMT MBC-6)

Background: Although there is no single accepted standard of care after failure of anthracycline and taxane therapy in HER2-negative metastatic breast cancer, capecitabine is a well-established treatment option. Bendamustine is a hybrid cytotoxic drug because of its structural similarity to alkylating agents and purine and it is generally well tolerated. Since bendamustine has already shown anticancer activity in breast cancer we evaluated the efficacy and tolerability of bendamustine in combination with capecitabine in 40 patients with advanced breast cancer after anthracycline and/or taxane pretreatment.

Patients and methods: MBC-6 is a non-randomized, multicenter, open-label, single-arm phase II study in patients with HER2-negative advanced breast cancer (ClinicalTrials.gov identifier: NCT01891227). All patients were pretreated with anthracyclines and/or taxans in the (neo-)adjuvant and/or metastatic setting and measurable disease according to RECIST 1.1. had to be present at baseline. Following a two-stage Green-Dahlberg design, 20 subjects were accrued and treated within stage 1 of the study. The trial was planned to enroll further 20 patients if there were at least four subjects (20%) with a complete (CR) or partial response (PR). Eligible patients received 1000 mg/m2 capecitabine twice daily on days 1 to 14 in combination with 80 mg/m2 bendamustine on day 1 and 8 of a 3-week cycle. After a maximum of eight cycles capecitabine was continued as single drug therapy until disease progression or unacceptable toxicity. The primary endpoint was overall response rate (ORR). Secondary endpoints were progression free survival (PFS), clinical benefit rate (CBR), safety profile and quality of life. Here we report the efficacy and safety analysis of stage 1 patients.

Results: From September 2013 to May 2015, 40 patients were recruited in eight Austrian centers. Median age of the stage 1 cohort was 59 years (range 29-77), 80% and 20% of patients had an ECOG performance score of 0 and 1, respectively. Thirty-three percent had triple-negative disease, 85% had had (neo-)adjuvant treatment and 65% patients were pretreated with at least one chemotherapy line for metastatic disease (15% one line, 50% two lines, 40% three lines). In stage 1, ORR was 50% with 9 confirmed PR and 1 confirmed CR, and ORR was comparable between hormone receptor-positive and triple-negative disease (54% vs. 43%). CBR was 55%. At data cut-off on 05/28/15 overall 15 of 20 patients had discontinued treatment: 10 patients (50%) due to progressive disease, 3 (15%) because of adverse events (AEs) and 2 patients on their own decision (10%). Five patients (25%) experienced at least one drug related non-hematological AE ≥ grade 3: 2 diarrhea, 2 fatigue, 3 respiratory or viral infections, 1 dyspnea, 1 thromboembolic event (each grade 3). One grade 4 hematological AE (neutropenia) was observed. One patient died as a result of restrictive cardiomyopathy, where a relationship to capecitabine cannot be excluded, but seems unlikely.

Conclusion: The combination of capecitabine and bendamustine has a moderate toxicity profile and the response data of the stage 1 are promising. Final study results are awaited in the first half of 2016.

Citation Format: Rinnerthaler G, Gampenrieder SP, Fridrik M, Petzer A, Hubalek M, Petru E, Jäger T, Andel J, Balic M, Ulmer H, Mlineritsch B, Greil R. Capecitabine in combination with bendamustine in pretreated women with HER2-negative metastatic breast cancer: Stage 1 results of a phase II trial (AGMT MBC-6). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-13-10.

[Investigation of the use of triclosan in patients with indwelling catheters: a randomized, double blind, multicenter, placebo-controlled clinical study]

BACKGROUND

This article presents the first randomized, double blind, multicenter, placebo-controlled, non-interventional trial with a medical product after approval by the ethical committee of the medical council of North-Rhine. The study investigated the use of the antimicrobial agent triclosan (Farco-fill® Protect) as a liquid for inflation of catheter balloons in patients with chronic indwelling catheters.

PATIENTS AND OBJECTIVES

In this study 84 patients were investigated (43 in the treatment group and 41 in the placebo group) all with a suprapubic catheter and a positive history of catheter incrustation. The catheters were changed after 6 weeks and endpoints were the quantitative analysis of the incrustation, weight of the catheter, pain during catheter change and the number of urinary tract infections. The maintenance of the catheter was a secondary endpoint.

RESULTS

The primary endpoint could not be reached because the study, which was initially planned with 70 patients in each arm, had to be terminated due to logistical and technical problems with the catheter weighing. The maintenance of the catheter as the most important clinical parameter showed statistically significant differences with a longer indwelling time in the triclosan group. Adverse events with respect to the product were not recorded.

CONCLUSIONS

Using the antimicrobial solution triclosan as a fluid for inflation of catheter balloons led to a statistically significant extension in the catheter indwelling time. The reduction of pain during changing the catheter and the reduction of incrustation, although not statistically significant, led to an improvement in the quality of life of these patients.

Rail or roll: a new, convenient and safe way to position self-gripping meshes in open inguinal hernia repair

PURPOSE

In open inguinal hernia repair self-gripping meshes are currently commonly employed. Assumed benefits are saving of time, ease of handling and omission of fixation. Self-gripping meshes are, however, not as easy to handle and position as commonly stated. We describe a newly developed way of intra-operative mesh preparation and implantation and compare it to the conventional technique of insertion of self-gripping meshes.

METHODS

A two-armed, randomized trial with 64 patients was performed. For implantation of the self-gripping, light weight and partially absorbable mesh we used either a newly described rolling technique (group 1: n = 32) or the conventional way of insertion (group 2: n = 32). Primary endpoints of the study were feasibility with regard to actual implantation time and surgeons' satisfaction with the methods. Secondary endpoints were total operating time, length of hospital stay, postoperative pain, duration of pain medication intake and postoperative morbidity. In addition all patients were prospectively followed up according to the Hernia Med® registry's standards.

RESULTS

Implantation time (seconds) 140 ± 74 vs. 187 ± 84, p = 0.008, duration of pain medication intake (days) 3.6 ± 2.8 vs. 4.8 ± 2.6; p = 0.046 and postoperative morbidity 2 (6%) vs. 8 (25%) was significantly beneficial in group 1 (rolling technique) compared to group 2 (conventional method). Blinded questionnaire revealed that rolling the mesh is generally easier with less repositioning maneuvers than conventional placement. Neither overall procedure time, length of stay nor postoperative pain scores differed significantly between groups.

CONCLUSION

The newly introduced rolling technique for the actual placement of self-gripping meshes in open inguinal hernia repair is technically less demanding and therefore significantly faster when compared to the conventional way of insertion of the same product. In addition the rolling technique has shown to be safe for the patients and to also provide higher surgeons' satisfaction.

Robust linear regression model of Ki-67 for mitotic rate in gastrointestinal stromal tumors

Risk stratification of gastrointestinal stromal tumors (GISTs) by tumor size, lymph node and metastasis status is crucially affected by mitotic activity. To date, no studies have quantitatively compared mitotic activity in hematoxylin and eosin (H&E)-stained tissue sections with immunohistochemical markers, such as phosphohistone H3 (PHH3) and Ki-67. According to the TNM guidelines, the mitotic count on H&E sections and immunohistochemical PHH3-stained slides has been assessed per 50 high-power fields of 154 specimens of clinically documented GIST cases. The Ki-67-associated proliferation rate was evaluated on three digitalized hot spots using image analysis. The H&E-based mitotic rate was found to correlate significantly better with Ki-67-assessed proliferation activity than with PHH3-assessed proliferation activity (r=0.780; P<0.01). A linear regression model (analysis of variance; P<0.001) allowed reliable predictions of the H&E-associated mitoses based on the Ki-67 expression alone. Additionally, the Ki-67-associated proliferation revealed a higher and significant impact on the recurrence and metastasis rate of the GIST cases than by the classical H&E-based mitotic rate. The results of the present study indicated that the mitotic rate may be reliably and time-efficiently estimated by immunohistochemistry of Ki-67 using only three hot spots.

Prolonged capnoperitoneum does not cause postoperative ileus in pigs: safety of prolonged capnoperitoneum

INTRODUCTION

Operative time is an accepted risk factor for the development of postoperative ileus (POI). Innovative surgical procedures such as robotic surgery and natural orifice transluminal endoscopic surgery (NOTES) will be associated with longer operative times. Although intraabdominal manipulation is a major factor for POI the impact of prolonged capnoperitoneum on postoperative gastrointestinal transit time (GIT-TT) has rarely been studied.

MATERIAL AND METHODS

IRB approved survival pilot study to assess postoperative GIT-TT using fecal collection and chromium-oxide (Cr2O3) labeling in pigs. Twelve female pigs were randomly assigned to three groups of four animals each. Group A received eight hours anesthesia and pressure-controlled high flow capnoperitoneum (15 mmHg), group B eight hours of anesthesia only and group C no intervention. No intraoperative manipulation. The pilot study was terminated after eight days.

RESULTS

None of the animals developed POI. In Group A one animal died after eight hours of general anesthesia. No differences in postoperative fecal output, Cr2O3 excretion rate or weight gain were found.

CONCLUSION

This study is the first to investigate eight hours of capnoperitoneum in a survival model. GIT-TT is not affected by prolonged capnoperitoneum in pigs. No POI occurred with prolonged capnoperitoneum. Prolonged capnoperitoneum is safe regarding postoperative gastrointestinal function in innovative surgical procedures.