October 4, 2011
Read this October 2011 document for a summary of key features about randomized controlled trials related to ovarian cancer screening
Ovarian cancer affects 2,500 women each year in Canada and approximately 60 per cent of them will die from it. This cancer is the fifth leading cause of cancer death for women.
Most women (70 per cent) are diagnosed after the cancer has spread and is either in stage three or four. The survival rate at advanced stages is only 15 to 20 per cent. When detected earlier, the survival rates are much higher: 90 per cent for stage one, and 66 to 69 per cent for stage two. Ovarian cancer rarely produces symptoms in its early stages that would alert a woman or her doctor.
Screening has been proposed as a strategy to detect ovarian cancer in its early stages when cure rates are higher. Several studies over the past 20 years have been published demonstrating the effect of screening with a blood test CA125, and transvaginal and pelvic ultrasound.
Several screening studies have been published in the past evaluating ovarian cancer screening, including three randomized controlled trials: PLCO, the United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS), and Japan’s Shizuoka Cohort study of Ovarian Cancer Screening Trial. This document summarizes key features of those trials, gives clinical context, helps to fill in knowledge gaps, and sets future direction.
Until the 2011 publication of the PLCO study abstract at ASCO (American Society of Oncology) none of the previously published studies evaluated the number of ovarian cancer deaths. Based on the results of the PLCO trial, the expert panel concluded that routine ovarian cancer screening should not be implemented on a population basis.