Impact of a diverting ileostomy in total mesorectal excision with primary anastomosis for rectal cancer.

BACKGROUND: The role of diverting ileostomy in total mesorectal excision (TME) for rectal cancer with primary anastomosis is debated. The aim of this study is to gain insight in the clinical consequences of a diverting ileostomy, with respect to stoma rate at one year and stoma-related morbidity. METHODS: Patients undergoing TME with primary anastomosis for rectal cancer between 2015 and 2017 in eleven participating hospitals were included. Retrospectively, two groups were compared: patients with or without diverting ileostomy construction during primary surgery. Primary endpoint was stoma rate at one year. Secondary endpoints were severity and rate of anastomotic leakage, overall morbidity rate within thirty days and stoma (reversal) related morbidity. RESULTS: In 353 out of 595 patients (59.3%) a diverting ileostomy was constructed during primary surgery. Stoma rate at one year was 9.9% in the non-ileostomy group and 18.7% in the ileostomy group (p = 0.003). After correction for confounders, multivariate analysis showed that the construction of a diverting ileostomy during primary surgery was an independent risk factor for stoma at one year (OR 2.563 (95%CI 1.424-4.611), p = 0.002). Anastomotic leakage rate was 17.8% in the non-ileostomy group and 17.2% in the ileostomy group (p = 0.913). Overall 30-days morbidity rate was 37.6% in the non-ileostomy group and 56.1% in the ileostomy group (p < 0.001). Stoma reversal related morbidity rate was 17.9%. CONCLUSIONS: The stoma rate at one year was higher in patients with ileostomy construction during primary surgery. The incidence and severity of anastomotic leakage were not reduced by construction of an ileostomy. The morbidity related to the presence and reversal of a diverting ileostomy was substantial.

18F-2-deoxy-2-fluoro-D-glucose positron emission tomography, computed tomography, and magnetic resonance imaging for the detection of experimental colorectal liver metastases.

During the treatment of colorectal liver metastases, evaluation of treatment efficacy is of the utmost importance for decision making. The aim of the present study was to explore the ability of preclinical imaging modalities to detect experimental liver metastases. Nine male Wag/Rij rats underwent a laparotomy with intraportal injection of CC531 tumor cells. On days 7, 10, and 14 after tumor induction, sequential positron emission tomography (PET), computed tomography (CT), and magnetic resonance imaging (MRI) scans were acquired of each rat. At each time point, three rats were euthanized and the metastases in the liver were documented histologically. Topographically, the liver was divided into eight segments and the image findings were compared on a segment-by-segment basis with the histopathologic findings. Sixty-four liver segments were analyzed, 20 of which contained tumor deposits. The overall sensitivity of PET, CT, and MRI was 30%, 25%, and 20%, respectively. For the detection of tumors with a histologic diameter exceeding 1 mm (n  =  8), the sensitivity of PET, CT, and MRI was 63%, 38%, and 38%, respectively. The overall specificity of PET, CT, and MRI was 98%, 100%, and 93%, respectively. This study showed encouraging detectability and sensitivity for preclinical imaging of small liver tumors and provides valuable information on the imaging techniques for designing future protocols.

Adjuvant radioimmunotherapy improves survival of rats after resection of colorectal liver metastases.

OBJECTIVE: The aim of this study was to test the hypothesis that adjuvant radioimmunotherapy (RIT) prevents recurrent liver metastases and/or results in improved survival after tumorectomy in an experimental model. BACKGROUND: Although partial hepatectomy can improve 5-year survival of patients with colorectal liver metastases up to 58%, recurrent tumor growth in the liver occurs frequently. Radioimmunotherapy using radiolabeled monoclonal antibodies directed against tumor-associated antigens is considered most suited for treating minimal residual disease and could therefore serve as an adjuvant after surgery. METHODS: Liver metastases were induced in male Wag/Rij rats by a mini-laparotomy with intrahepatic injection of 0.3 × 106 CC531 tumor cells. The biodistribution of the radiolabeled monoclonal antibody MG1, directed against a 80-kDa cell surface antigen on CC531 tumors, in this model was determined at 1, 3, and 7 days after intravenous administration. The therapeutic efficacy of 177Lu-MG1 was compared with that of a sham antibody (UPC10), labeled with the same activity dose of Lu-177, and saline only. Radioimmunotherapy was administered either at the day of the tumorectomy (day 14 after tumor cell inoculation) or 7 days later. Primary endpoint was survival. RESULTS: Radiolabeled MG1 preferentially accumulated in tumor lesions in the liver reaching a maximum 3 days postinjection (8.7 ± 0.6% injected dose per gram). Both the administration of 177Lu-MG1 and 177Lu-UPC10 resulted in a transient decrease in body weight. No other signs of clinical discomfort were registered. The survival curves of the group that received 177Lu-UPC10 and the group that received saline only did not differ (P=0.886). Administration of RIT immediately after surgery improved survival compared to administration of the control antibody (hazard ratio [HR], 1.54; P = 0.051), which was even more pronounced when survival was adjusted for the weight of the resected tumor (HR, 1.71; P = 0.027). A therapeutic efficacy of delayed treatment seemed likely (HR, 2.34; P = 0.055). Survival after early administration did not differ from delayed administration (HR, 1.16; P = 0.763). CONCLUSION: This study provides proof of principle that RIT can be an effective adjuvant treatment modality after surgical treatment of colorectal liver metastases.

Radioimmunotherapy improves survival of rats with microscopic liver metastases of colorectal origin.

BACKGROUND: Half of the patients with colorectal cancer develop liver metastases during the course of their disease. The aim of the present study was to assess the efficacy of radioimmunotherapy (RIT) with a radiolabeled monoclonal antibody (mAb) to treat experimental colorectal liver metastases. METHODS: Male Wag/Rij rats underwent a minilaparotomy with intraportal injection of 1 x 10(6) CC531 tumor cells. The biodistribution of (111)In-labeled MG1, 1 day after intravenous administration, was determined in vivo and compared with that of an isotype-matched control antibody (UPC-10). The maximal tolerated dose (MTD) of (177)Lu-labeled MG1 was determined and the therapeutic efficacy of (177)Lu-MG1 at MTD was compared with that of (177)Lu-UPC-10 and saline only. RIT was administered either at the day of tumor inoculation or 14 days after tumor inoculation. Primary endpoint was survival. RESULTS: (111)In-MG1 preferentially accumulated in CC531 liver tumors (9.2 +/- 3.7%ID/g), whereas (111)In-UPC-10 did not (0.8 +/- 0.1%ID/g). The MTD of (177)Lu-MG1 was 400 MBq/kg body weight. Both the administration of (177)Lu-MG1 and (177)Lu-UPC-10 had no side-effects except a transient decrease in body weight. The survival curves of the group that received (177)Lu-UPC-10 and the group that received saline only did not differ (P = 0.407). Administration of (177)Lu-MG1 RIT immediately after surgery improved survival significantly compared with administration of (177)Lu-UPC-10 (P = 0.009) whereas delayed treatment did not (P = 0.940). CONCLUSION: This study provides proof of principle that RIT can be an effective treatment modality for microscopic liver metastases, whereas RIT is not effective in larger tumors.

Animal models for liver metastases of colorectal cancer: research review of preclinical studies in rodents.

Liver metastases of colorectal carcinoma occur in about 50-60% of patients. To improve survival of these patients, there is an urgent need for new treatment strategies. For this purpose, the availability of a preclinical model to develop and test such treatments is mandatory. An ideal animal model for studying liver metastases of colorectal origin should mimic all aspects of the metastatic development in humans and be practical, predictable, and optimal in terms of ethical considerations. Thus far, no model has been developed which satisfies all these conditions. As a consequence, choosing an animal model for the study of liver metastases requires compromises and choices about the necessary characteristics that depend on the purpose of the intended experiments. This overview addresses the advantages and disadvantages of different animal models used for research on experimental liver metastases of colorectal origin. Based on data available in literature, we conclude that heterotopic injection of undifferentiated syngeneic tumor cells in immunocompetent rodents covers most of the desired characteristics. Both subcapsular as well as intraportal injection will yield suitable models and the eventual choice will depend on the aim of the study.

Diagnosing Internal Herniation After Roux-en-Y Gastric Bypass Surgery: Literature Overview, Cadaver Study and the Added Value of 3D CT Angiography.

PURPOSE: The purposes of the study are to outline the complexity of diagnosing internal herniation after Roux-en-Y gastric bypass (RYGB) surgery and to investigate the added value of computed tomography angiography (CTA) for diagnosing internal herniation. MATERIALS AND METHODS: A cadaver study was performed to investigate the manifestations of internal hernias and mesenteric vascularization. Furthermore, a prospective, ethics approved study with retrospective interpretation was conducted. Ten patients, clinically suspected for internal herniation, were prospectively included. After informed consent was obtained, these subjects underwent abdominal CT examination, including additional arterial phase CTA. All subjects underwent diagnostic laparoscopy for suspected internal herniation. The CTA was used to create a 3D reconstruction of the mesenteric arteries and surgical staples (3D CTA). The 3D CTA was interpreted, taking into account the presence and type of internal hernia that was found upon laparoscopy. RESULTS: Cadaveric analysis demonstrated the complexity of internal herniation. It also confirmed the expected changes in vascular structure and surgical staple arrangement in the presence of internal herniation. 3D CTA studies of the subjects with active internal hernias demonstrated remarkable differences when compared to control 3D CTA studies. The blood supply of herniated intestinal limbs in particular showed abnormal trajectories. Additionally, enteroenterostomy staple lines had migrated or altered orientation. CONCLUSION: 3D CTA is a promising technique for diagnosing active internal hernias. Our findings suggest that for diagnosing internal hernias, focus should probably shift from routine abdominal CT examination towards the 3D assessment of the mesenteric vasculature and surgical staples.