Low-grade serous carcinoma (LGSC): A Canadian multicenter review of practice patterns and patient outcomes Stephanie A. Scott a, ⁎, Marta Llaurado Fernandez b , Hannah Kim b , Laurie Elit c , Melica Nourmoussavi d , Sarah Glaze e , Lesley Roberts a , Saul L. Offman a , Kurosh Rahimi f , Alice Lytwyn g , Monalisa Sur h , C. Blake Gilks b , Kara Matheson a , Martin Köbel i , Amy Dawson b , Anna V. Tinker b , Janice S. Kwon b , Paul Hoskins b , Jennifer L. Santos b , Andrea Cheung b , Diane Provencher d , Mark S. Carey b , the Canadian LGSC Community of Practice (GOC-CoP) a Department of Obstetrics and Gynecology, Dalhousie University, Halifax, Nova Scotia, Canada b Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, British Columbia, Canada c Juravinski Cancer Centre, Hamilton Health Sciences, Hamilton, Ontario, Canada d Division of Gynecologic-Oncology, Centre Hospitalier de Université de Montréal, (CHUM) and Centre de recherche du CHUM, Montreal, Quebec, Canada e Tom Baker Cancer Centre, Alberta Health Services, Calgary, Alberta, Canada f Department of Pathology, Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada g Department of Pathology and Molecular Medicine, Health Research Methods, Evaluation, and Impact (HEI), McMaster University, Hamilton, Ontario, Canada h Department of Pathology and Molecular Medicine, McMaster University and The Juravinski Hospital and Cancer Centre, Hamilton, Ontario, Canada i Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, Alberta, Canada HIGHLIGHTS • Treatment practices and outcomes for LGSC patients differ across Canada and are influenced by institutional factors. • Site of primary origin, institution, residual disease status and age were significant predictors of OS and/or PFS. • Decreased PFS and other poor prognostic factors were associated with the use of neoadjuvant chemotherapy. • PFI and TTNT times were remarkably consistent (b10 months) following first relapse regardless of treatment type. • Future research and quality improvement initiatives are needed to improve outcomes for patients with LGSC. abstract article info Article history: Received 23 August 2019 Received in revised form 28 November 2019 Accepted 13 January 2020 Available online xxxx Keywords: Low-grade serous carcinoma Ovarian cancer Practice patterns Outcomes Objective. Patients with advanced low-grade serous carcinoma (LGSC) have poor long-term survival rates. As a rare histotype, there are uncertainties regarding the use of current therapies. Thus, we studied practice patterns and treatment outcomes as part of a national initiative to better understand and improve the care of women with advanced LGSC. Methods. This retrospective cohort study was conducted in 5 Canadian referral institutions from 2000 to 2016. Data collection and pathology reporting were standardized. Outcome measures included overall survival (OS), progression-free survival (PFS), progression-free intervals (PFI), and time to next treatment (TTNT). Cox regres- sion analysis was used to evaluate the effects of clinical and pathologic factors on outcomes and prognosis. Results. There were 134 patients (stage II-IV) with a median follow-up of 32.4 months (range 1.6-228). Four primary treatments were compared across institutions: 1) surgery followed by chemotherapy (56%), 2) neoadju- vant chemotherapy (NACT) followed by surgery (27%), 3) surgery alone (9%), and 4) surgery followed by anti- hormone therapy (4%). Primary platinum/paclitaxel chemotherapy was used in 81%. Patients treated with NACT had worse PFS. Multivariable Cox regression analysis identified lesser residual disease, younger age, and primary peritoneal origin as variables significantly associated with better OS/PFS (p b 0.03). One institution had significantly better PFS than the others (p = 0.025), but this finding could be related to a higher frequency of primary peritoneal LGSC. PFI and TTNT intervals in patients with relapsed disease were not significantly differ- ent after the first relapse irrespective of treatment type. Gynecologic Oncology xxx (xxxx) xxx ⁎ Corresponding author at: Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Dalhousie University, Halifax, Nova Scotia, Canada. E-mail address: StephanieA.scott@nshealth.ca (S.A. Scott). YGYNO-977812; No. of pages: 10; 4C: https://doi.org/10.1016/j.ygyno.2020.01.021 0090-8258/© 2020 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Gynecologic Oncology journal homepage: www.elsevier.com/locate/ygyno Please cite this article as: S.A. Scott, M. Llaurado Fernandez, H. Kim, et al., Low-grade serous carcinoma (LGSC): A Canadian multicenter review of practice patterns and patient ou..., Gynecologic Oncology, https://doi.org/10.1016/j.ygyno.2020.01.021