A new study lends some hope for a more effective method to screen for ovarian cancer, and hopefully detect it in an earlier stage when curative surgery is more likely.
Ovarian cancer is the leading cause of death from a gynecological malignancy in the United States. There were an estimated 21,980 cases diagnosed in 2014 with an expected 14,270 deaths attributable to this type of cancer. This malignancy carries a poor prognosis, with a five-year survival rate of just under 50 percent; despite increases in radical surgical approaches and improved targeted therapies, prognosis has not improved in the last three decades.
There has always been an interest to develop methods of early detection and reducing ovarian cancer deaths and maintaining cost-effectiveness of a screening program. In the latest issue of The Lancet, the results of the largest-ever randomized trial has demonstrated that screening for ovarian cancer does indeed improve mortality rates attributable to this disease by an estimated 20 percent.
The prognosis for women who are diagnosed early in the stage of disease is far better than the more common late-stage diagnosis: early stage ovarian cancer has a survival rate of over 90 percent in five years, but this number drastically goes down as the disease is diagnosed in later stages.
The very unfortunate fact remains, that in most cases, the cancer is not diagnosed until it has already spread beyond the ovaries; this occurs in roughly 75 percent of cases. The reason is because most often the symptoms are vague and nonspecific, and by the time the cancer is detected it has had time to spread.
The study, the United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS), is the third and largest randomized controlled trial ever with up to a 15 year follow-up, aimed at assessing whether or not screening improved diagnosis and prognosis of women diagnosed with ovarian cancer. The screening tests consisted of multimodal screening (MMS) using an ovarian cancer marker CA-125 and an annual transvaginal ultrasound, or just an ultrasound, versus no screening.
The trial, led by Professor Ian Jacobs, Institute for Women s Health, University College London and colleagues, enrolled 202,638 post-menopausal females in a 1:1:2 ratio for two screening tests or control. To date, it is the first study of its kind to produce findings that show that in postmenopausal women from the general population, annual screening with use from the multimodal strategy is safe and could reduce deaths due to ovarian cancer.
The primary end-point was mortality benefit from ovarian cancer. When excluding women with undiagnosed ovarian cancer when joining the trial, the data revealed that there was earlier detection of ovarian cancer with screening, and a significant mortality benefit in the long term. The MMS was able to detect cancer earlier in 59 percent and 51 percent in the ultrasound only group.
The downside to this trial was that even with the screening, cancers were detected only in 59 percent of ovarian cancer cases in both groups. The survival benefit was not seen in enough patients to comfortably say that MMS be recommended for everyone.
These results from UKCTOCS provide estimates of the mortality reduction attributable to ovarian cancer screening, which range from 15% to 28%," said Professor Jacobs, in a written statement. "Further follow up in UKCTOCS will provide greater confidence about the precise reduction in mortality which is achievable. It is possible that the mortality reduction after follow up for an additional 2-3 years will be greater or less than these initial estimates.
The results from this trial are encouraging, however, more research is needed to develop better screening strategies for this very devastating cancer.