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Identifying a New Diagnostic Test for Early-Stage Ovarian Cancer

A new study led by USC Norris Comprehensive Cancer Center developed a liquid biopsy that may distinguish between cancerous and benign pelvic masses with up to 91% accuracy. These earlier insights could help improve choices about course of treatment.

High-grade serous ovarian carcinoma (HGSOC) is the most common type of ovarian cancer. It is also the most lethal form in part because clinicians do not have effective ways to screen women for it during the cancer’s early stages when it’s easiest to treat.

For patients with a pelvic mass, it is difficult to detect whether the growth is benign or cancerous ahead of surgery. Unlike for many other cancers, biopsies are typically not an option. That makes it hard for doctors to choose the best course of treatment.

Now, a new liquid biopsy that detects specific nucleic acids circulating in the blood may be poised to change that.

Preclinical research recently published in the journal Clinical Cancer Research suggests that this simple blood test may determine whether a pelvic mass is benign or cancerous at a better rate than existing tests.

“There is a need for physicians to know what they’re dealing with before surgery,” said Lynda Roman, MD, a gynecologic oncologist at USC Norris Comprehensive Cancer Center, part of Keck Medicine of USC, and co-author of the study. “This test will help in starting to find a way to diagnose this disease early.”

Knowing more about the mass before surgery could point to which type of surgeon and which method of surgery is best for a patient, Roman said.

In addition to helping health care providers choose the best treatment strategy for patients with a known pelvic mass, researchers will also investigate whether the new test can be used as a screening tool in the general population to detect early-stage ovarian cancer in asymptomatic women.

When ovarian cancer is found in its initial stages, patients have a more than 90% chance of living for five years or more. Their chances drop to less than 40% if the cancer is detected in advanced stages.

Bringing the test to patients

The researchers are launching a follow-up study to validate their results in hundreds of patients. If the follow-up study results validate the efficacy of the test, they plan to release a commercially viable version of the test for clinical use within two years.

They are also exploring whether the test can be modified to detect other subtypes of ovarian cancer. Ultimately, they aim to optimize the test so it can be used for broad population screening.

According to Roman, the test’s potential impact on diagnostics for ovarian cancer is a welcome advancement for the field.

“Since we know that many malignant masses start in the fallopian tube, often the standard has become removing the fallopian tube whenever you operate on a patient, and then focusing on treatment,” Roman said. “But knowing what you’re dealing with before surgery could save lives, as well as improve our use of limited resources.”

A focused approach

The test uses a cell-free DNA methylation liquid biopsy approach, a promising new way to detect early-stage cancers of various types. It searches for circulating DNA in the blood that has been methylated at certain nucleic acids.

By testing for these early molecular changes, the test was designed to identify HGSOC when the cancer is in an early stage, and relatively easy to treat, unlike most existing tests for ovarian cancer which do not detect early-stage cancer at a high rate. 

“Outside of germ cell tumors that have highly reliable tumor markers, we otherwise encounter masses that have several indicators that may hint one way or the other — including radiologic characteristics and certain blood tests — but none of these is highly reliable,” Roman said.

The new test’s 91% accuracy rate means it has both high sensitivity and high specificity, while most other tests on the market are high in one and low in the other, according to Bodour Salhia, PhD, leader of the Epigenetic Regulation in Cancer Program at USC Norris and the study’s corresponding author.