Formal discussant of this trial, Usha Menon, MD, Professor of Gynecological Oncology at the Institute for Women’s Health, University College, London, raised several important issues about the design of the PLCO trial particularly related to the dilution of the screening effect due to prolonged follow-up of women after the end of screening and the lack of a well-defined screening strategy with both first- and second-line tests, fixed timelines, and protocol-driven management, which has been repeatedly shown to play a crucial role in attaining a mortality impact in cervical cancer. Most of the deaths occur in women with type II ovarian cancer (high-grade serous, high-grade endometrioid, and undifferentiated cancers). She said that it is questionable whether screening can have an impact on mortality in ovarian cancer unless effective treatment strategies are found for the 80% that recur in this group. A better understanding of the natural history of the disease is therefore crucial.
Based on current evidence, ovarian screening cannot be recommended in the general population, and “opportunistic” screening of asymptomatic low-risk women with CA-125 is not advisable, Prof. Menon stated.
“This does not mean that screening for ovarian cancer will not work. We just have not yet found a screening strategy that can impact mortality,” she told the audience.
She said that future screening trials should incorporate serial changes when measuring markers as well as quality assessment. “The search for better biomarkers should continue. Also, we need a better understanding of the natural history of the disease, because it is unclear if ovarian cancer is amenable to screening,” she stated. ■
Disclosure: Prof. Menon is joint principal investigator on the UK Ovarian Cancer Screening Trial. Her group has a research collaboration with Becton Dickinson, which has an interest in tumor markers and ovarian cancer. She has a financial interest through UCL Business and Abcodia Ltd in the third-party exploitation of clinical trials biobanks, which have been developed through the research at UCL.
Using a CA-125 blood test combined with transvaginal ultrasound for early detection of ovarian cancer failed to reduce the risk of mortality associated with the disease and led to a large number of false-positive tests with unnecessary related biopsies and other follow-up procedures in the large,...