352. Gene and MicroRNA Expression Predictive of Tumour Response in Patients Treated with Preoperative Chemoradiotherapy for Rectal Cancer

ABSTRACTS Results: There were no postoperative deaths. One patient (8,3%) developed anastomotic leakage, which required reoperation and colostomy. Two patients (16,6%) developed anastomotic stricture, which was treated conservatively. No other significant complications were observed. All 11 patients who had successful restorative operations had satisfactory continence and sphincter function. Conclusions: This technique may simplify the surgical approach to re~ procedure, especially for patients with short rectal versal of HartmannOs stump radiation-induced pelvic fibrosis. 349. The Dependence Between Concentration of EGFR and Also P21protein and Prognosis in Rectal Cancer Disease S. Gluszek1, M. Kozlowska1, J. Matykiewicz1, P. Lewitowicz2, D. Koziel2 1 Wojewodzki Szpital Zespolony, Genaral Oncological and Endocrine Surgery, Kielce, Poland 2 The Faculty of Health University of Jan Kochanowski, Kielce, Poland Background: The aim of our research was studyinfluence concentration of EGFR and p21-protein on prognosis at patients withrectal cancer disease. Material and methods: In our research participated 105 patientswith rectal cancer disease in I-III degree (TNM classification). All of themoperated in 2005-2010. At the first step we were analyse a medical documents our patients, especially: risk factors, results of their examinations, a sortof operation and course of events after operation, at last a results ofpathological tests. At the second time we were use immunochemical methods to account a concentration of EGFR and p21protein in after operation specimens. At the last step we were compare influence concentration of EGFR and p21-proteinto five-years survival our patients. Results: Among a patients with rectal cancer who were take a part in our research 62% survived in five-years time of observation without local renewal rectal disease, 21% to be alive with local renewal disease, 8,5% to be alive with diffuse cancer disease, and 8,5% were die. Conclusions: Our initially research proved that the patients with high concentration of p21-protein and low concentration forger have a higher chance to five-years survive without local renewal rectal cancer disease. 352. Gene and MicroRNA Expression Predictive of Tumour Response in Patients Treated with Preoperative Chemoradiotherapy for Rectal Cancer I. Maretto1, G. Spolverato1, S. Pucciarelli1, M. Agostini1, M. Digito1, K. Tavella1, C. Millino2, B. Pacchioni2, B. Celegato2, D. Nitti1 1 Clinica Chirurgica II, Dip. Scienze Chirurgiche Oncologiche e Gastroenterologiche, Padova, Italy 2 Microarray Service, CRIBI - University of Padova, Padova, Italy Background: The response of rectal cancer to preoperative chemoradiotherapy (pCRT) is not uniform. There is no effective method of predicting tumour response to pCRT. Identification of patients not responsive to pCRT could avoid useless exposure to radiation or chemotherapy that is associated with adverse effects. This study aimed to investigate whether gene and micro-RNA (miRNA) expression profiling is associated with rectal cancer response to pCRT. Material and methods: Tumour biopsies were obtained from patients with mid-low rectal cancer, before pCRT. All the patients underwent standard pCRT followed by resection. All surgical specimens underwent standardized histopathological examination. The biopsies with 50% of tumour tissue were considered for the experiment. Gene and miRNA expression was analyzed using one color microarrays technique (AgilentÒ), after RNA isolation. The data were normalized intra- and inter-array, filtered and then clustered. Gene and miRNA expression was compared between responders (R) and non responders (NR) as measured by histopathological tumour regression grade (TRG) using SAM (Significance Analysis of Microarrays) two class. Validation of microarrays data was made by qPCR.

839 Results: Thirty-eight patients, 16 (42%) R (TRG1-2) and 22 (58%) NR (TRG3-5) were considered. Of 26330 genes analyzed, 256 were differentially expressed between R and NR (188 over- and 68 down-expressed). Performing PAM (Prediction Analysis for Microarray), we found 8 genes strongly predictive of tumour response. Of 159 miRNAs analyzed, 30 were differentially expressed between R and NR (24 over- and 6 down-expressed). ABCC2 gene, miR-200a, miR-182, miR-630, and miR-1300 were validated by qPCR. Conclusions: Pre-treatment gene and miRNA expression profiling of rectal adenocarcinoma seems to be helpful in predicting response to pCRT. Further analyses to confirm the results obtained in a new clinical comparable cohort of patients are required. 353. Tumor Characteristics and Their Relationship to Colorectal Cancer Relapse S.T. Makkai-Popa1, F. Zugun2, S.O. Georgescu1, P. Popa1, E. Carasevici2, E. Tarcoveanu1 1 "SF-Spridon" Hospital, First Surgical Clinic, Iasi, Romania 2 "SF-Spridon" Hospital, Genetics and Immunology Laboratory, Iasi, Romania Background: The purpose of this retrospective study is to assess a link between different characteristics of the tumor (other than TNM staging) and the probability of a cancer relapse after the patient has been operated on with a curative purpose. Materials and method: We selected 39 patients (14 patients with metastases and 25 patients with local relapse) out of a total of 96 patients presenting in our clinic between 2007 and 2011 with local relapse or metastases. Results: We analyzed tumor characteristics such as distance between the tumor and the resection margins, tumor grading and histological type of the tumor, presence or absence of a colloid component, percentage of invaded lymph nodes from the total number of lymph nodes resected, presence of inflammation and the type of inflammation, perineural invasion and tumor emboli. From a histological point of view we found that 80,55% (29 patients) had a moderately differentiated tumor, 11,11% (4 patients) had a well differentiated tumor and 8,33% (3 patients) had a low differentiated tumor. 50% (19 patients) were graded as G2 tumors, while 7,89% (3 patients) were graded as G1 and 15,78% (6 patients) were graded as G3. 17, 94% (7) of the patients showed a colloid component, with 2 of these patients (5,12% of the study group) having developed a metastasis and 5 patients (12,82% of the study group) having a local relapse. 61,76% (21) of the patients had under 50% of the resected lymph nodes invaded, 16 of these patients having been included in this study for a local relapse. Conclusion: From our results it would seem that some of these characteristics such as the percentage of invaded lymph nodes could be used as a prognostic marker alongside the histological characteristics of the tumor. Unfortunately we also found out that some of the criteria we tried to correlate to the behavior of the tumor (inflammation for example) are not assessed in every patient and this is the reason why the retrospective, in depth study of the tumor both from the point of view of the cancer cell characteristics and the point of view of the stroma is a direction we are approaching in trying to find new prognostic markers for colorectal cancer. 354. Surgical Anatomy of Perianorectal Connective Tissue Structures and Spaces in Relation to Locally Advanced Low Rectal Cancer Surgery D. Dardanov1, V. Stoyanov2 1 Hospital "Sofiamed", Department of Surgery, Sofia, Bulgaria 2 Medical Institute - Ministry of Interior, Department of Surgery, Sofia, Bulgaria Background: In the last years oncological results after rectal cancer surgery has improved due to modern standardized techniques of rectal mobilization. However there are many differences in describing the plane of rectal mobilization and contradicting anatomical statements. The aim of