It is particularly difficult to detect ovarian cancer during its earliest stages, driving researchers to try and find new ways to make quicker diagnoses.
The new screening method involves the interpretation of changes in levels of CA125, a specific protein associated with ovarian cancer, in women's blood. The conventional ovarian cancer screening method uses a fixed "cut-off" point for CA125, meaning that the new method is able to predict a woman's individual risk of developing cancer with greater accuracy.
Women can have higher levels of CA125 in their blood than this cut-off point and not have ovarian cancer while other women can have lower levels of the protein yet develop the disease.
Prof. Ian Jacobs, current president of the University of New South Wales, Australia, conceived the trial. He explains the importance of the findings:
"CA125 as a biological marker for ovarian cancer has been called into question. Our findings indicate that this can be an accurate and sensitive screening tool, when used in the context of a woman's pattern of CA125 over time. What's normal for one woman may not be so for another. It is the change in levels of this protein that's important."
The researchers conducting the trial found that the new method detected cancer in 86% of women with invasive epithelial ovarian cancer compared with conventional methods used in prior trials or clinical practice that could identify only 41% and 48% respectively.
At present, the UK does not have a national ovarian cancer screening program as research has yet to suggest that any one particular strategy would improve rates of early tumor detection.
"These results are therefore very encouraging," explains trial co-ordinator Prof. Usha Menon. "They show that use of an early detection strategy based on an individual's CA125 profile significantly improved cancer detection compared to what we've seen in previous screening trials."
The trial originated from part of the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS), the largest ovarian cancer screening trial in the world.
A total of 202,638 post-menopausal women aged 50 and over participated in UKCTOCS and were randomly assigned to receive either annual multimodal screening, transvaginal ultrasound or no test at all.
Researchers hope new method can provide earlier ovarian cancer diagnoses
For the new study, published in the Journal of Clinical Oncology, the researchers followed up 46,237 women who continued to receive annual multimodal screening. Each participant would have their CA125 levels tested annually over the course of 14 years.
With the help of a computer algorithm, the researchers calculated their risk of ovarian cancer according to the woman's age, their original CA125 levels and how those levels had changed over time. The risk of ovarian cancer was then estimated by comparing the serial pattern with known cases of cancer and controls.
Within the group of women receiving multimodal screening, 640 had surgery for suspected cancer. Of these, 133 had invasive epithelial ovarian cancers. Another 22 women were diagnosed with epithelial ovarian cancer within one year of their final annual screen. The researchers will receive results on the impact of screening on ovarian cancer deaths later in the year.
"The numbers of unnecessary operations and complications were within acceptable limits," states Prof. Menon. "While this is a significant achievement, we need to wait until later this year when the final analysis of the trial is completed to know whether the cancers detected through screening were caught early enough to save lives."
"My hope is that when the results of UKCTOCS are available, this approach will prove capable of detecting ovarian cancer early enough to save lives," says Prof. Jacobs.
Dr. James Brenton, an expert in ovarian cancer with Cancer Research UK, says that it is vital that ways to diagnose the cancer sooner are found. "A blood test to find women at risk of ovarian cancer is an exciting prospect, but this work still needs to be tested in women to see if it can save lives," he states.
Recently, Medical News Today reported on the discovery of a new biomarker that could improve the prospects for ovarian cancer patients by indicating how their bodies are likely to react to chemotherapy.