dichotomize MMR status and by combining cases with epigenetic and probable genetic causes rather than treating them as etiologically and clinically distinct groups. doi:10.1016/j.ygyno.2015.01.047 46 — Focused Plenary Homologous recombination deficiency in endometrioid uterine cancer: An unrecognized phenomenon J.M. Hansen, K.A. Baggerly, Y. Wang, S. Wu, R.A. Previs, B. Zand, H.J. Dalton, W. Hu, R.L. Coleman, A.K. Sood. The University of Texas MD Anderson Cancer Center, Houston, TX, USA Objectives: PTEN mutations are frequently observed in endometrioid uterine cancer and lead to hyperactivation of the PI3K/Akt pathway. However, the role of BRCA1 and 2 mutations, leading to homologous recombination deficiency, is not known in this disease. We sought to determine the frequency and clinical significance of BRCA mutations in patients with uterine cancer and PTEN mutations. Methods: We assessed PTEN, BRCA1, and BRCA2 mutation status for 248 uterine tumor samples using level 3 data from The Cancer Genome Atlas (TCGA). We performed mutation analysis for PTEN, BRCA1, and BRCA2 for an additional 251 samples from TCGA using ANNOVAR. A total of 499 patients were included in the analysis. Clinical data, including stage, tumor histology, and overall survival, were also extracted. Fisher's exact tests were used to identify the association between mutation status and histologic subtype. Kaplan–Meier plots were constructed to demon- strate survival differences between groups. Results: Among the samples analyzed, 335 (67%) had endometrioid histology, 76 (15%) had serous histology, 18 (44%) had mixed histology, and histology was unknown in the remainder of cases. Of the patients with endometrioid histology, 260 (78%) had a PTEN mutation, 23 (7%) had both BRCA1 and 2 mutations, 4 (1%) had mutations in BRCA1 only, and 25 (8%) had mutations in BRCA2 only. A total of 52/335 patients (16%) had mutations in either BRCA1 or 2; 18/52 (35%) of these had stage II or above disease and the remainder had stage I disease. No survival advantage was detected in patients with BRCA1 mutations over wild- type BRCA1, independent of PTEN mutation status (P = 0.16 and 0.19, respectively). Patients with both PTEN and BRCA2 mutations had improved overall survival compared to patients with wild-type PTEN and BRCA2 (P = 0.03). A single mutation in BRCA1, BRCA2, or PTEN did not confer a significant survival advantage compared to wild-type (P = 0.15). Conclusions: BRCA1 and 2 mutations are prevalent in patients with endometrioid uterine cancer, and PTEN/BRCA2 double mutations are associated with prolonged patient survival. These findings may have significant clinical and treatment implications. doi:10.1016/j.ygyno.2015.01.048 Focused Plenary III — Novel Approaches to Surgery Monday, March 30, 2015 Moderator: Heidi J. Gray, MD, University of Washington Medical Center, Seattle, WA Camille Catherine Gunderson, MD, The University of Oklahoma, Oklahoma City, OK 47 — Focused Plenary ROMA guided conservative management for women diagnosed with an ovarian cyst or pelvic mass E. Lokich a , M. Palisoul b , N. Romano c , A.R. Stuckey c , K.M. Robison c , P.A. DiSilvestro c , C. Mathews c , M.C. Miller b , C.O. Granai c , R.G. Moore c . a Brown University, Women and Infants Hospital, Providence, RI, USA, b Brown University, Women and Infant's Hospital, Providence, RI, USA, c Women and Infants Hospital, Brown University, Providence, RI, USA Objectives: Results-oriented management assessment (ROMA) has been cleared by the United States Food and Drug Administration to assist non-oncology physicians in risk assessment of a pelvic mass and to triage women at high risk for malignancy to gynecologic oncologists. Most women presenting with a pelvic mass have benign disease, and many who are asymptomatic still have surgery. The objective of this study was to evaluate the use of ROMA to assist in identifying women who can safely undergo conservative management. Methods: All patients referred to Women's Oncology with a pelvic mass are evaluated at our multidisciplinary tumor board (TB), where ROMA and imaging are used to reach management recommendations. This institutional review board-approved trial evaluated women presented to the TB from 2009 to 2012 with a pelvic mass who had either surgical or conservative management. Patient demographics, imaging, ROMA scores, TB recommendations, and pathology were collected. Basic statistical parameters were determined. Results: Among the 500 patients eligible for analysis (173 pre- and 327 postmenopausal), the median age was 56 years (range: 15–90 years). There were 392 patients with benign disease, 22 with low malignant potential (LMP) tumors, 28 with stage I–II epithelial ovarian cancer (EOC), 36 with stage III–IV EOC, and 20 with non-EOC. Initial TB recommendation for patient management had a sensitivity for detecting malignancy of 100% (95% CI: 95.7–100%), specificity of 47.8% (95% CI: 42.8–52.9%), and negative predictive value (NPV) of 100% (95% CI: 98.0–100%). Actual patient management had a sensitivity of 98.8% (95% CI: 93.5–100%), specificity of 46.0% (95% CI: 41.0–51.1%) and NPV of 99.4% (95% CI: 97.0–100%). ROMA alone for the detection of EOC had a sensitivity of 95.3% (95% CI: 86.9–99.0%), specificity of 65.6% (95% CI: 60.6–70.3%), and NPV 98.8% (95% CI: 96.7–99.8%). For Stage I–II EOC, ROMA had a sensitivity of 89.3% (95% CI: 71.8–97.7%). All 84 malignancies, including 28 early-stage EOC, were recommended for surgery. Only 1 of 22 patients with an LMP tumor was assigned to observation. Clinical assessment in conjunction with ROMA identified 187 (37.4%) women for conservative management. Conclusions: ROMA, in conjunction with clinical assessment, can safely identify women for conservative management. No women with a malignancy were assigned to the observation group, and one third of patients who were originally referred for consideration for surgery safely underwent conservative management. doi:10.1016/j.ygyno.2015.01.049 48 — Focused Plenary Impact of sentinel lymph node mapping on FIGO stage and GOG risk stratification in early endometrial cancer: A comparative analysis R.W. Holloway, S. Gupta, N.M. Stavitzski, E.L. Takimoto, A. Gubbi, L.A. Brudie, J.E. Kendrick IV, S. Ahmad. Florida Hospital Cancer Institute, Orlando, FL, USA Objectives: To determine the impact of sentinel lymph node (SLN) mapping on FIGO stage and Gynecologic Oncology Group (GOG) risk stratification in patients with endometrial cancer by comparing patients surgically staged with and without SLN mapping. Methods: A robotic surgery database was queried for endometrial cancer cases (07/2006 to 06/2013) that underwent robotic hyster- ectomy with pelvic ± aortic lymphadenectomy. A total of 781 cases were identified that had N 8 pelvic lymph nodes (LNs) resected: Group A had pelvic ± aortic lymphadenectomy (n = 662) and Group B had SLN mapping with lymphadenectomy (n = 119). SLN mapping was accomplished with isosulfan blue dye and indocyanine green with near-infrared imaging. Patients were staged by FIGO 2009 criteria and assessed for GOG risk stratification. Criteria compared in both groups were clinicopathologic data, FIGO stage, GOG risk, and postoperative therapies. Abstracts / Gynecologic Oncology 137 (2015) 2–91 21