Relative survival rates for colon cancer comparing number of positive nodes to total nodes resected: An analysis of 311,093 patients

ASSOCIATION FOR ACADEMIC SURGERY AND SOCIETY OF UNIVERSITY SURGEONS—ABSTRACTS tion rates. Results: There was significant large-area variation in surveillance intensity, according to the US Census Region in which the surgeon practiced. Non-US respondents employed several modalities significantly more often than US respondents (p ⬍ 0.05). Smallarea variation (MSA) was not significant. Surveillance patterns varied significantly (p ⬍ 0.05) by MCO penetration rate for office visit and CT of the abdomen and pelvis but not for other modalities. Conclusion: The intensity of post-treatment patient surveillance following completion of primary curative-intent therapy for rectal cancer patients is affected statistically significantly by the US Census Region in which the surgeon practices; The MSA in which the surgeon practices does not affect surveillance intensity significantly and MCO penetration rate affects follow-up intensity minimally; All significant differences are rather modest clinically. These data should be useful in the design of controlled trials on this topic. The authors will propose such a trial at the meeting. 220. THE IMPACT OF IMATINIB ON DIAGNOSIS AND OUTCOMES OF GIST: A POPULATION-BASED EXAMINATION. Perez EA, Livingstone AS, Franceschi D, Rocha-Lima C, Lee DJ, Hodgson N, Jorda M, Koniaris LG; University of Miami Objective: Gastrointestinal stromal tumors (GISTs) have been recognized as the most common mesenchymal tumor of the GI tract. New effective chemotherapies have been defined for the treatment of GIST but have not been validated by phase III trials. We sought to determine both current population-based incidence and if improved outcomes noted in both individual centers and clinical trials have also been observed in a large prospective cancer registry. Materials and Methods: The Surveillance, Epidemiology and End Results (SEER) database thirteen-center cumulative tumor registry (April 2005 release) was queried from 1992-2002 to determine incidence and associated outcomes for patients diagnosed with GIST. Confirmation of incidence trends were confirmed using the incident Florida Cancer Data System, which is the largest non-SEER registry in the US (FCDS, 2005 release). Results: A twentyfivefold age-adjusted increase in incidence of GIST from 0.028 per 100000 in 1992 to 0.688 per 100000 in 2002 was observed. This increase is mostly due to reclassifying smooth-muscle tumors as GISTs but also represents a fifty percent increase in population and age-adjusted gastrointestinal mesenchymal tumor diagnosis since 1992. Despite rising GIST incidence rates, there was a marked improvement in survival since 2000 coinciding with the introduction of the tyrosine kinase inhibitor imatinib into clinical practice. Conclusions: The diagnosis of GIST has dramatically increased since 1992. Survivals have dramatically improved since 2000. Proper diagnosis is critical to identify those patients who will benefit from adjuvant imatinab chemotherapy. This is the first report to demonstrate a population-based marked survival benefit for patients with GIST coincident with the introduction of imatinib. 221. RELATIVE SURVIVAL RATES FOR COLON CANCER COMPARING NUMBER OF POSITIVE NODES TO TOTAL NODES RESECTED: AN ANALYSIS OF 311,093 PATIENTS. B. Heniford, A. Lincourt, R. Sing, Y. Novitsky, A. Stewart, F. Greene; Carolinas Medical Center, Charlotte, NC Background: When predicting survival of colon cancer without distant metastases, the size of the tumor and number of positive lymph nodes (LN) play a major role. However, measuring the number of positive LN as compared to the total number of nodes resected and its effect on patient survival has not been well described. Methods: Patients (n ⫽ 311,093) with stage I-III colon cancer reported to the National Cancer Data Base from 1990-1998 were analyzed. Cases were excluded if the patients had metastases, were not a traditional resection, or if neo-adjuvant therapy was given. Patients with a 5-year follow-up were included. The patients were divided into groups of total LN resected by quartiles: Group 1: ⱕ6 LN, Group 2:

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7-11 LN, Group 3: 12-16 LN, Group 4: ⱖ17 LN. 95% confidence intervals were utilized for statistical comparisons. Results: When comparing all cancers, regardless of primary tumor size, patients with 0-4 and 6-8 positive LN had statistically improved survival when Group 4 was compared to Groups 1 and 2; Group 3 only offered an advantage compared to Group 1 and 2 if no LN were positive. The same was true when the larger (T3/T4) cancers were analyzed; when 0-8 LN were positive, Group 4 patients had a improved survival compared to Groups 1 and 2. Again, Group 3 offered an advantage only when no LN were positive. In T1 and T2 cancers, survival was essentially equal in all groups except in Group 4 patients when compared to Group1 when no LN were positive. Conclusion: An adequate node dissection is important for staging and possible cure of colon cancer patient. While en bloc removal of 12 LN traditionally signifies an adequate resection, 17 or greater lymph nodes provides a survival advantage in patients with up to 8 positive LN in T3 and T4 lesions when compared to 11 or less LN. Greater LN resection in patients with no positive LN provides improved survival regardless of tumor size. 222. LAPAROSCOPIC APPENDECTOMY IN CHILDREN: AFTER THE LEARNING CURVE. Vegunta RK, Rawlings A, Woodland J, Wallace LJ, Torres Jr A, Ali A, Pearl RH; University of Illinois College of Medicine at Peoria Purpose: To analyze the effect of operator experience on outcomes, we evaluated the results following laparoscopic appendectomy for a pre-operative diagnosis of appendicitis, comparing our first forty consecutive cases to the most recent forty consecutive cases. Method: Patient information was retrospectively collected with Institutional Review Board approval. Hospital medical charts and out patient clinic charts of the 80 applicable patients were reviewed and data was analyzed using SPSS 12.0 for Windows. Results: Our first forty cases of laparoscopic appendectomy for acute appendicitis were performed between May 1999 and May 2002. The most recent forty were performed between July 2003 and June 2004. There was no significant difference in the duration of surgery between the two groups (p ⫽ 0.1). The rates of normal appendices in the two groups were 20 and 13 percent respectively. The proportion of ruptured appendicitis was similar. There was no significant difference in the rate of conversion to open appendectomy (p ⫽ 0.5). The total complication rate was 28 and 20 percent respectively. The total complication rate was lower despite the lower normal appendix rate (20 vs. 12.5%), but did not reach statistical significance (p ⫽ 0.4). The mean length of hospital stay for the early and late groups, was 4.4 days and 2.6 days respectively which was statistically significant (p ⫽ 0.002). Conclusion: Laparoscopic appendectomy is known to be feasible and safe in all stages of acute appendicitis in children. The current analysis shows that, with experience, one can achieve further improvements in results and lower the cost of taking care of patients with acute appendicitis as evidenced by significantly lower length of hospital stay and lower complication rates.

223. RIVES-STOPPA RETROMUSCULAR REPAIR FOR INCISIONAL HERNIAS. Clark CJ, Fisher M, Walker G, Muscarella P; The Ohio State University Department of General Surgery