Optical coherence tomography (OCT) and multispectral fluorescence imaging (MFI) have demonstrated promising results in the early detection of ovarian cancer, as detailed in an abstract presented at the 12th Biennial Ovarian Cancer Research Symposium, held September 13–15 in Seattle.
“There appear to be unique markers in the blood of ovarian cancer patients, months and years prior to diagnosis, and optical imaging techniques can distinguish [between] normal, cancer, and benign abnormalities [in] ovarian and fallopian tube tissue,” said presenter Jennifer K. Barton, PhD, professor of biomedical engineering at the University of Arizona in Tucson.
Barton and colleagues are developing a screening test for early (ie, premetastatic) ovarian cancer. The development of an early screening method is important because late ovarian cancer diagnosis results in a 5-year survival rate markedly below 50%.
“If the cancer can be identified while still confined to the fallopian tube, a very high survival rate is expected,” noted Barton.
Experts hypothesize that a substantial proportion of ovarian high-grade serous carcinoma (HGSC) actually begins in the fallopian tubes before spreading to the ovary and peritoneal cavity. Optical imaging approaches could help detect primary HGSC precancerous changes at the level of the fallopian tubes.
Barton and colleagues recently developed the smallest-diameter (0.8 mm) OCT/MFI imaging endoscope to date for the navigation through the natural orifice of the ostium of the uterus.
“In a small ex vivo study, we found that 5 MFI measurements were sufficient to distinguish between normal, cancerous, and benign fallopian tube and ovary tissue with 100% sensitivity and specificity,” the authors wrote. “We used laparoscopic OCT in an in vivo study of 17 women and revealed distinct image features for normal, cancerous, and benign abnormalities of the ovary.”
This minimally invasive imaging endoscope, however, is not intended for population-wide screening. Instead, the investigators propose using it as an adjunct confirmatory test.
“If these findings hold true in larger studies, it may be possible to develop a two-step ovarian cancer screening tool, where the first step is a blood test to identify women with possibly abnormal blood markers, and the second step is a minimally invasive falloposcopy with advanced optical imaging capabilities to look for any abnormalities in the fallopian tubes and ovaries,” said Barton.
The investigators have already identified potential serum HGSC protein biomarkers for the blood test, including FBG and PF4, which have a lead time of between 18 and 84 months. They have also verified a three-biomarker panel (FBG, PF4, and CA125) that classifies HGSC with more than 80% sensitivity and more than 70% specificity, and has a lead time of between 18 and 84 months. Finally, they identified overexpression of various glycolytic enzymes in serous tubal intraepithelial carcinoma lesions and human prediagnostic serum samples that could serve as screening biomarkers.
“Our continuing work is focused on refining the serum protein biomarker sensitivity and specificity, creating a second-generation falloposcope for a first-in-women feasibility study, and creating an integrated model that incorporates both sets of data into an early EOC detection method,” concluded the authors.