Most women with epithelial ovarian cancer have circulating tumor cells, and among those who recently received their cancer diagnosis, the more such cells they had, the shorter their survival times, according to new research.

While the findings provide useful tool for a clinical setting, researchers urge larger studies to validate the results and examine if the approach brings real value to ovarian cancer care.

The study, “Predictive value of circulating tumor cells (CTCs) captured by microfluidic device in patients with epithelial ovarian cancer,” appeared in the journal Gynecologic Oncology.

Doctors already count circulating tumor cells as a biomarker to diagnose and predict several cancers, including breast cancer.

While some studies link circulating tumor cells in patients with ovarian cancer with a worse prognosis and an advanced disease stage, researchers at Korea’s Seoul National University College of Medicine underscored that earlier studies did not consider factors — such as the method of isolating and detecting cells — that might have influenced the interpretation of results.

To better understand the role of circulating tumor cells in ovarian cancer, the team recruited 54 women, 24 of which had been newly diagnosed and 30 had a recurrence of disease. They detected circulating tumor cells in 98.1 percent of the sample. Cell counts did not differ in women with varying tumor stages, and were not linked to levels of the cancer marker CA-125.

Among the 32 women with clusters of cells in their blood (as opposed to single cells), 62.5 percent resisted treatment with platinum chemotherapy, and an analysis revealed a link between the two factors. They also discovered that newly diagnosed patients with three or more cancer cells in their blood sample had a significantly shorter progression-free survival. Those with more circulating tumor cells progressed after a median of 14 months, compared to 23 months among those with fewer than three cells.

Even so, cell count had no impact on overall survival times. And among those with recurrent disease, researchers found no link between cell counts and either progression-free or overall survival, nor between the presence of cell clusters and survival.