Abstract LB-273: Prognosis and conditional disease-free survival among ovarian cancer patients
Authors: Kurta Michelle , Edwards Robert , Moysich Kirsten , McDonough Kathleen , Bertolet Marnie , Weissfeld Joel , Catov Janet , Modugno Francesmary , Bunker Clareann , Ness Roberta , Diergaarde Brenda 
Published: May 2015

Abstract
Background: Survival estimates are traditionally reported from the time of diagnosis or remission. Although these estimates provide important information, they are not necessarily still applicable to patients who have already survived a period of time after their initial diagnosis and treatment. Conditional disease-free survival accounts for elapsed time since achieving remission and may offer more relevant prognostic information to patients and their clinicians. More accurate information about risk of recurrence will not only allow patients and clinicians to make better informed decisions regarding follow-up care after cancer treatment but may also improve quality of life by ameliorating patients’ fear of recurrence. This study aimed to estimate conditional disease-free survival among ovarian cancer patients and to identify factors that impact disease-free survival. To our knowledge, no prior studies have assessed conditional disease-free survival among ovarian cancer patients. Patients and Methods: We used data collected as part of the Hormones and Ovarian Cancer Prediction (HOPE) case-control study; in total, 404 cases, all of whom had achieved remission after a diagnosis of ovarian cancer, were included in the current analyses. The majority of patients were Caucasian, median age at diagnosis was 58.6 years, and 5.5% had a family history of ovarian-only or breast and ovarian cancer. Demographic and lifestyle information was collected at enrollment; disease and clinical characteristics, including follow-up data, were abstracted from medical records. Disease-free survival was calculated using the Kaplan-Meier method. Conditional disease-free survival estimates were computed using cumulative disease-free survival estimates. Results: Median disease-free survival was 2.54 years (range: 0.03-9.96 years) and 3-year disease-free survival was 48.2%. The probability of surviving an additional 3 years without recurrence, conditioned on having already survived 1, 2, 3, 4, and 5 years after remission, was 63.8%, 80.5%, 90.4%, 97.0% and 97.7%, respectively. Initial differences in disease-free survival at time of remission between age, stage, histology and grade groups diminished over time. Conclusion: Disease-free survival estimates for ovarian cancer patients improved dramatically over time, in particular among those with poorer initial prognoses. Our results demonstrate that conditional disease-free survival is a more relevant measure of prognosis for ovarian cancer patients who have already achieved a period of remission and that time elapsed since remission should be taken into account when making follow-up care decisions.
Citation Format: Michelle Kurta, Robert Edwards, Kirsten Moysich, Kathleen McDonough, Marnie Bertolet, Joel Weissfeld, Janet Catov, Francesmary Modugno, Clareann Bunker, Roberta Ness, Brenda Diergaarde. Prognosis and conditional disease-free survival among ovarian cancer patients. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-273. doi:10.1158/1538-7445.AM2014-LB-273