An eagerly anticipated clinical trial shows lifesaving potential for a method to screen for ovarian cancer using annual CA-125 tests and ultrasound. The algorithm used in the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS), whose results are published in The Lancet, reduced the risk of death from ovarian cancer an estimated 20 percent.
Ovarian cancer accounts for 1 in 20 cancer deaths in U.S. women, and causes more deaths than any other gynecological malignancy. Although survival is good when ovarian cancer is detected early, most ovarian cancers are diagnosed at an advanced stage when prognosis is poor.
The conventional approach to detect ovarian cancer early has focused on testing with a serum cancer antigen 125 (CA-125) and transvaginal ultrasound, but results to date have been disappointing. No organization recommends ovarian cancer screening.
Now, promising new results from the new trial have renewed hope for a modified approach.
Dr. Ian Jacobs and colleagues studied approximately 200,000 women over more than a decade to determine whether multi-modal screening (MMS) with a “risk of ovarian cancer algorithm” (ROCA), a quantitative algorithm based on age, risk status and CA-125 levels over time, was effective in reducing ovarian cancer mortality compared with ultrasound alone or usual care.
After a median follow-up of 11 years, the authors observed a nonsignificant 15% fewer deaths in the MMS group, but when the cases diagnosed in the first screening round were taken out of the analysis, a statistically significant 20% reduction in ovarian cancer mortality was observed. Why the adjustment? They say many of the deaths from ovarian cancer in the study group were because the cancer was already advanced at the time of the first screening exam.
The authors caution that more study is needed to better understand the efficacy and cost effectiveness of ovarian cancer screening.
We asked Robert Smith, Ph.D., vice president of cancer screening, for his thoughts on this eagerly anticipated study.
“There has been great interest in screening for ovarian cancer for as long as I’ve been involved in cancer, but until now there has been no evidence that the conventional approach of using a fixed cutoff CA-125 level combined with ultrasound was an effective approach.
“The findings are incredibly encouraging. We have known for some time that the ROCA appeared to have better performance, but until now, we did not have data that it was effective in reducing ovarian cancer deaths.
“But it’s important to note that this approach to testing also was associated with a high rate of invasive procedures and complications associated with false positive findings.
“The investigators are appropriately cautious, and agree that these findings are not sufficient to begin recommending that postmenopausal women start screening.
“However, the findings do mean that there is renewed urgency to answer unanswered questions to determine if and when screening for ovarian cancer might be recommended.
“As part of its ongoing guidelines development process, the American Cancer Society will review this new evidence and closely monitor on-going evaluation of the UKCTOCS data.”
You can read more about ovarian cancer, including statistics, risk factors, treatment and more here.