Ovarian Cancer Screening Test Remains Elusive
Ovarian cancer is one of the deadliest forms of cancer affecting women. This is in part because symptoms are usually vague, especially early in the disease, and they often go unnoticed until the cancer has spread. Some of these symptoms, which can appear with other conditions, include feeling bloated, loss of appetite or feeling full quickly, needing to urinate more frequently, and pelvic or abdominal pain.
More than half of ovarian cancer patients have advanced disease (Stage 3 or 4) at the time of diagnosis. The American Cancer Society estimates that over 20,000 women will be newly diagnosed with ovarian cancer this year, and more than 13,000 will die of the disease. This type of cancer mainly occurs in post-menopausal women, with about half of cases affecting those aged 63 years and older.
Although scientists have been looking for a way to detect ovarian cancer in the early stages (when it is most treatable), there is no reliable screening test yet. Some of the most promising screening strategies that have been researched are measuring and monitoring the blood levels of a protein called CA-125 and/or the use of transvaginal (TV) ultrasound (in which the ultrasound transducer is placed within the vagina).
However, results from a large study—the United Kingdom Collaborative Trial of Ovarian Cancer Screening—were recently published in The Lancet and showed that these two particular screening methods do not reduce deaths from ovarian cancer, which is the ultimate goal of cancer screening. Given these results, the researchers conclude that these methods, alone or in combination, are not recommended for general population screening.
For the study, researchers looked at data from over 200,000 post-menopausal women aged 50 to 74 years who were followed for an average of 16 years. The women were randomly assigned to one of three groups: no screening; yearly screening with TV ultrasound; or yearly screening with CA-125 blood tests followed by TV ultrasound, if CA-125 results were elevated over time.
Results of the study show that screening in the TV ultrasound group found no more cases of ovarian cancer compared with the no screening group. While the researchers discovered that the combined CA-125 and TV ultrasound method found 39% earlier stage ovarian cancers (Stage 1 or 2) compared with the no screening group, the earlier detection did not save lives.
The reason for this is not clear, but researchers believe there is evidence the cancers detected were very aggressive and difficult to treat, despite early detection. Additionally, these results may indicate that ovarian cancers need to be detected even earlier and in a larger population of women in order to affect survival rates.
Researching, developing, and evaluating an effective and reliable screening strategy may be many years in the future, explain the study authors. The study results provided valuable data for future research, as well as biological samples that will help improve the understanding of ovarian cancer.
Meanwhile, all women are encouraged to stay tuned-in to what is normal or abnormal for their bodies, and they should consult their healthcare provider if experiencing any concerning symptoms.
Menon U, et al. Ovarian cancer population screening and mortality after long-term follow-up in the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS): a randomised controlled trial. The Lancet, 2021; DOI: 10.1016/S0140-6736(21)00731-5.
University College London. (2021, May 13). Screening for ovarian cancer did not reduce early deaths. ScienceDaily. Accessed June 1, 2021 from www.sciencedaily.com/releases/2021/05/210513173552.htm
(May 12, 2021) Gallagher, James. Ovarian cancer: Setback as major screening trial fails to save. BBC News. Accessed June 1, 2021 from https://www.bbc.com/news/health-57087477