EP958 - Propensity Matched Comparison of Surgical Outcomes Between Minimally Invasive and Open Resection of Non-Metastatic Appendiceal Neoplasms

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Purpose/Background: Appendiceal neoplasms (AN) are a rare, heterogenous group of tumors with varying malignant potential based on histology and stage. Despite being exceedingly uncommon, with an age adjusted rate of 6 per million cases, there remains an up to 1.4% chance any appendectomy performed may be found to be an AN. Colonic resection is recommended for advanced appendiceal neoplasms for appropriate staging and disease control. Our study evaluated differences in surgical outcomes based on operative approach for non-metastatic AN undergoing colectomy at their primary surgery.

Methods/Interventions: Data from the 2004-2019 American College of Surgeons’ National Cancer Database was queried to identify patients who underwent at least partial colectomy for all types appendiceal neoplasms. Minimally invasive surgery was defined as laparoscopic or robotic surgery and open surgery included MIS approaches that were subsequently converted to open. Patients missing information on the type of surgery (minimally invasive or open) or those with metastatic disease were excluded. Variables evaluated included minimally invasive vs open surgery, extent of surgery (partial colectomy, hemicolectomy, or total colectomy), sex, race, Hispanic ethnicity, insurance type (private, Medicaid/Medicare, unfunded), Charleson-Deyo comorbidity index, pathologic T and N stage). Propensity score matching (PSM) was used to compare 30-day mortality, 90-day mortality, 30-day readmissions, average last contact and surgical margins controlling for patient factors and extent of colectomy performed.

Results/Outcomes: A total of 12,656 patients were identified that underwent colonic resection for non-metastatic appendiceal neoplasms between 2004-2019 with documented Minimally Invasive Surgery (MIS) (n=8824) or Open (n=3832) procedures. Patients undergoing open resection had longer mean hospital stay, higher 30-day mortality, 90-day mortality, and 30-day unplanned readmissions but lower rates of negative surgical margins and average last contact (Table). After 1:1 PSM (N=4412), these groups were well balanced. Differences in mean length of hospital stay, last contact, 30-day readmission risk, 30-day mortality, and 90-day mortality persisted but both groups had no difference in rates of negative margins.

Conclusion/Discussion: Although MIS is increasingly recommended for colorectal cancer, there is limited data on outcomes after resection for appendiceal neoplasms specifically. In this study of patients with nonmetastatic appendiceal neoplasms, surgical outcomes studied here are improved when a MIS approach is chosen over an open approach. The decreased readmission and postoperative mortaility rates persist when matching for patient factors, cancer stage, and extent of colectomy performed. A MIS approach should be considered when colon resection is performed for nonmetastic appendiceal neoplasms.