Early changes linked to ovarian cancer may leave a trace in the blood—new study
The most common type of ovarian cancer tends to grow quickly. It's called high-grade serous ovarian cancer and often starts in a fallopian tube, one of the tubes that carry eggs from the ovaries toward the uterus.
A new study indicates that early changes associated with ovarian cancer might be detectable in the blood. High-grade serous ovarian cancer, a common type, often begins in a fallopian tube and can spread to nearby tissue. Researchers discovered that storing blood samples from patients revealed higher levels of a molecule called Tu-stroma in those with early cancer that had infiltrated nearby tissue.
This molecule, which is a type of RNA, was also found at elevated levels in individuals with a small patch of abnormal cells known as serous tubal intraepithelial carcinoma (STIC). STIC is considered an early step towards high-grade serous ovarian cancer. The study's next phase involves observing individuals over time to determine when these signals first appear.
Currently, ovarian cancer is typically diagnosed based on symptoms such as persistent bloating and abdominal pain, though these symptoms can also be associated with other conditions. A blood test for CA125, a protein whose levels can rise with ovarian cancer, is sometimes used to screen for the disease. However, other conditions can also elevate CA125 levels.
The U.K. lacks a routine screening program for asymptomatic individuals for ovarian cancer. Tu-stroma, an RNA molecule, represents a potential biomarker for early detection. Earlier research showed that ovarian cancer cells can release Tu-stroma in extracellular vesicles, microscopic parcels that facilitate cell-to-cell communication.
The researchers measured the quantity of Tu-stroma in the blood using these parcels. In a cohort of 506 individuals, including 43 with STIC, the test detected STIC in 92% of cases, while it identified no STIC in 98% of healthy controls. The test demonstrated greater accuracy in distinguishing STIC from healthy individuals and noncancerous growths adjacent to the ovaries or fallopian tubes compared to CA125.
However, the findings are preliminary, as the study relied on samples from patients with confirmed diagnoses. Given the limited number of STIC cases, the results are uncertain, and widespread use of Tu-stroma detection could lead to a high number of false positives, causing undue anxiety and unnecessary interventions. BRCA1 and BRCA2 gene mutations, which heighten the risk of ovarian cancer, may prompt some individuals to consider preventive surgery to remove their ovaries and fallopian tubes, thus reducing their risk but also eliminating their fertility.
The National Institute for Health and Care Excellence (NICE) advises that specialist teams may consider regular CA125 testing for certain high-risk individuals who opt to delay or forgo surgery. Tu-stroma could potentially enhance monitoring for such high-risk patients. For now, the absence of any warning signs detected by the blood test does not negate the recommendation for surgery.
A large U.K. screening trial employing CA125 did not conclusively demonstrate a reduction in mortality from ovarian or fallopian tube cancers. Future research must ascertain the frequency at which STIC aberrant cells progress to nearby tissue and the implications of a positive blood test accompanied by negative imaging. Ultimately, a screening trial would need to determine whether acting upon Tu-stroma results leads to improved survival outcomes.
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