Southern California Chapter of American College of Surgeons Annual Scientific Meeting The American Surgeon 2020, Vol. 86(10) 1358–1362 © The Author(s) 2020 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/0003134820964460 journals.sagepub.com/home/asu Treatment Factors Associated With Overall Survival in Retroperitoneal Sarcoma: An Institutional Review Mei L. Kwong, MD 1 , Becky Lee, MD 1 , Karissa Kunihira, MD, MA 2 , Brian Sutjiadi, BS 2 , Mark E. Reeves, MD 1,2 , Matthew Selleck, DO 1,2 , Gary Yang, MD 1,2 , and Naveenraj Solomon, MD 1,2 Abstract Introduction: Retroperitoneal sarcoma (RPS) is a rare malignancy, and curative resection is considered the main therapy. Use of chemotherapy and/or radiation in addition to surgery (multimodality therapy) is controversial. Objective: To determine treatment factors that influence overall survival in RPS. Methods: This retrospective Institutional Review Board-approved study identified patients with RPS treated at a single institution between 2000 and 2017. Patient, tumor, and treatment modalities were collected. Prism (v.8.2.1) was used to calculate Kaplan-Meier survival curves. Results: There were 695 patients with sarcoma between 2000 and 2017, and 61 adults had RPS. The mean age was 59 (range 31-86) years, with 57.4% females (n = 35). Patients were 68.9% Caucasian (n = 42), 21.3% Hispanic (n = 13), 8.2% black (n = 5), and 1.6% Asian (n = 1). There were 4 patients who had neoadjuvant therapy (chemotherapy, n = 3; radiation, n = 2) and 17 who had adjuvant therapy (chemotherapy, n = 6; radiation, n = 14). There was no significant difference in survival between the groups who received multimodality therapy compared to surgery alone. There was a significant improvement in the median overall survival for patients who underwent one or multiple surgeries (P < .05). Conclusions: These institutional data suggest that treatment factors associated with overall survival included multiple resections. Use of multimodality therapy was low and did not influence overall survival in patients with RPS compared to surgery alone. Keywords retroperitoneal, sarcoma, multimodality therapy Introduction Retroperitoneal sarcoma (RPS) is a rare malignancy, and curative resection is considered the main therapy. Due to the size of tumors and proximity to essential structures, complete microscopic resection despite radical surgery can be difficult. Failure of local control, not distant me- tastases, has the greatest deleterious impact on survival. Local recurrence rates are high, and therefore multi- modality treatment to decrease recurrence therefore is attractive. Use of chemotherapy and/or radiation in ad- dition to surgery differs among institutions due to con- troversy regarding its effectiveness. Due to the low incidence of RPS, most evidence of treatment efficacy is based on retrospective and single-institution experiences rather than randomized control trials. Current National Comprehensive Cancer Network guidelines state that surgical resection of localized RPS with negative margins is the standard of care. 1 This constitutes radical en bloc resection of involved organs with tumor to increase the rate of negative margins. 2-4 A large single institution series demonstrated a median survival of 103 months vs. 18 months for patients who 1 Loma Linda University Health, Loma Linda, CA, USA 2 Loma Linda University School of Medicine, Loma Linda, CA, USA Corresponding Author: Naveenraj Solomon, MD, Loma Linda University Health, 11175 Campus St, 21111, Loma Linda, CA 92350, USA. Email: nsolomon@llu.edu