Real-world evidence in the treatment of ovarian cancer

Introduction: 'Real-world evidence (RWE)' refers to information on the utilization and outcome of new therapies and technologies in clinical practice. RWE may include single institution cohort studies, population-based health services studies, or (inter)national data on survival and mortality. This paper reviews RWE on the impact of treatment in ovarian cancer.

Materials and methods: A literature review of publications addressing population level survival outcomes of new surgical and systemic treatment interventions in ovarian cancer was undertaken. In addition, literature and international cancer registry trends in ovarian cancer survival, mortality and incidence rates were compiled. These latter were utilized to make inferences on the relative impact of new treatments as well as changing incidence rates on observed mortality trends.

Results: The last four decades have seen new systemic and surgical treatments introduced into practice for ovarian cancer based on randomized trial evidence. However, there has been little published on population level uptake and survival outcomes of those interventions. Exceptions were population studies on intraperitoneal chemotherapy and neoadjuvant chemotherapy. One paper demonstrated modest uptake of intraperitoneal chemotherapy and evidence of improved survival. Cancer registry statistics revealed falling incidence rates (∼1%-2% per year) for ovarian cancer across Europe, North America and elsewhere over the last three to four decades. Mortality rates also declined by ∼1%-2% per year over this period. Population 5-year relative survival estimates also improved over this period [from 33.7% in 1975 to 46.2% in 2008 (SEER data)].

Conclusions: There are few RWE studies of specific treatments in ovarian cancer. Trends in relative survival and population mortality have shown improvements. Mortality changes can be explained in part by reductions in ovarian cancer incidence rates (speculated to be due to use of oral contraceptives and reduction in postmenopausal hormone use). However, it is plausible that at least some of the mortality reduction is related to improved survival of patients with the introduction of effective new treatments.