Most — and possibly all — ovarian cancers do not start in ovaries but instead in the fallopian tubes, which are attached to them, claims a recent study. The new findings also point to the possibility that removing a woman’s fallopian tubes, but not her ovaries, may reduce risk of ovarian cancer in those at high risk for disease, including those with genetic changes (mutations) known to increase risk (e.g. BRCA).
Senior study author Douglas A. Levine from New York University’s school of medicine said that based on a better understanding of its origins, the study suggests new strategies for the prevention and early detection of ovarian cancer. The results revolve around the fallopian tubes, which enable egg cells that have the potential to be fertilised and become embryos to pass from the ovaries where they are made to the uterus.
The new study found that ovarian cancer cells have more in common with cells covering the tips of fallopian tubes than with those on the surface of ovaries. If biomarkers can be found for these tubal cells, then according to researchers, future blood tests, advanced Pap smears, or direct tests on tubal tissue might be able to detect the ovarian cancer earlier.
“We are one of several centres taking part in Women Choosing Surgical Prevention or WISP trial, which seeks to determine whether removing the tubes improves quality of life, compared to removing both the tubes and ovaries,” Levine stated. Despite the remaining uncertainties, the current study does confirm previous results that had suggested that many high-grade serious cancers in the pelvis are preceded by abnormal cells (lesions) occurring in the fallopian tubes, called serous tubal intraepithelial carcinoma (STIC).
Cancer cells may arise from nearby tissue or may have spread to a location from another part of the body, but their genetic profile reflects the tissue of origin. Thus, the researchers knew going in that if STIC cells and ovarian cancer cells had different genetic profiles, they must have originated in different tissue types. Instead, in-depth molecular analyses of cells from 96 women with high-grade serous carcinoma failed to identify any genetic differences between cancer cells arising in the tubes and serous “ovarian” cancers occurring elsewhere in the pelvis.
They found no differences in the 20,000 genes that they can identify. “This leads us to believe that these ovarian cancers all originate in the fallopian tubes,” Levine noted. Ovarian cancer is more aggressive than many other cancers because it is hard to diagnose in its earliest and most treatable stages.
Fewer than 50% of women diagnosed with the disease survive for longer than five years after their diagnoses, according to the American Cancer Society. The research appears in Nature Communications journal.