Reclassification of serous ovarian carcinoma by a 2-tier system

A Gynecologic Oncology Group Study


  • The following Gynecologic Oncology Group member institutions participated in this study: University of Alabama at Birmingham, Duke University Medical Center, Abington Memorial Hospital, University of Rochester Medical Center, Walter Reed Army Medical Center, Wayne State University, University of Minnesota Medical School, Emory University Clinic, University of Mississippi Medical Center, Colorado Gynecologic Oncology Group P.C., University of California at Los Angeles, University of Washington, University of Pennsylvania Cancer Center, Milton S. Hershey Medical Center, Georgetown University Hospital, University of Cincinnati, University of North Carolina School of Medicine, University of Texas Southwestern Medical Center at Dallas, Indiana University School of Medicine, Wake Forest University School of Medicine, Albany Medical College, University of California Medical Center at Irvine, Tufts-New England Medical Center, Rush-Presbyterian-St. Luke's Medical Center, SUNY Downstate Medical Center, University of Kentucky, Community Clinical Oncology Program, The Cleveland Clinic Foundation, Johns Hopkins Oncology Center, State University of New York at Stony Brook, Eastern Pennsylvania GYN/ONC Center, P.C., Washington University School of Medicine, Cooper Hospital/University Medical Center, Columbus Cancer Council, University of Massachusetts Medical School, Fox Chase Cancer Center, Medical University of South Carolina, Women's Cancer Center, University of Oklahoma, University of Virginia Health Sciences Center, University of Chicago, Tacoma General Hospital, Thomas Jefferson University Hospital, Case Western Reserve University, Tampa Bay Cancer Consortium, North Shore University Hospital, Gynecologic Oncology Network, Oregon Health Sciences University, University of Southern California at Los Angeles, University of Miami School of Medicine, Stanford University Medical Center, Eastern Virginia Medical School, University of Arizona Health Science Center, Mayo Clinic, and Long Island Jewish Medical Center.



A study was undertaken to use the 2-tier system to reclassify the grade of serous ovarian tumors previously classified using the International Federation of Gynecology and Obstetrics (FIGO) 3-tier system and determine the progression-free survival (PFS) and overall survival (OS) of patients treated on Gynecologic Oncology Group (GOG) Protocol 158.


The authors retrospectively reviewed demographic, pathologic, and survival data of 290 patients with stage III serous ovarian carcinoma treated with surgery and chemotherapy on GOG Protocol 158, a cooperative multicenter group trial. A blinded pathology review was performed by a panel of 6 gynecologic pathologists to verify histology and regrade tumors using the 2-tier system. The association of tumor grade with PFS and OS was assessed.


Of 241 cases, both systems demonstrated substantial agreement when combining FIGO grades 2 and 3 (overall agreement, 95%; kappa statistic, 0.68). By using the 2-tier system, patients with low-grade versus high-grade tumors had significantly longer PFS (45.0 vs 19.8 months, respectively; P = .01). By using FIGO criteria, median PFS for patients with grade 1, 2, and 3 tumors was 37.5, 19.8, and 20.1 months, respectively (P = .07). There was no difference in clinical outcome in patients with grade 2 or 3 tumors in multivariate analysis. Woman with high-grade versus low-grade tumors demonstrated significantly higher risk of death (hazard ratio, 2.43; 95% confidence interval, 1.17-5.04; P = .02).


Women with high-grade versus low-grade serous carcinoma of the ovary are 2 distinct patient populations. Adoption of the 2-tier grading system provides a simple yet precise framework for predicting clinical outcomes. Cancer 2012;118: 3087–94. © 2011 American Cancer Society.