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Contrast-enhanced ultrasound finds angiogenesis in early ovarian cancer.

Researchers are closer to a non-invasive test for early ovarian cancer, according to data presented yesterday in San Francisco at the American College of Obstetricians and Gynecologists' 58th Annual Clinical Meeting.

The researchers' study tested the feasibility of combining contrast-enhanced Doppler ultrasound (US) imaging with measurement of circulatory and cellular markers of tumor-associated neo-angiogenesis.

For the contrast medium, they used Optison, which is currently approved for cardiovascular imaging. Optison "enhances visualization of blood vessels in the ovary," Dr. Animesh Barua from Rush University Medical Center, Chicago, told Reuters Health. "We also need to find a marker in serum to identify women at high risk who should undergo ultrasound screening."

Dr. Barua and associates are conducting their experiments in laying hens, the only widely available spontaneous model of ovarian cancer. He noted that unlike induced tumors in rodents, spontaneous ovarian tumors in chickens are similar to those in humans in histology, metastatic behavior, and stages.

Optison "remarkably" enhanced the detection of ovarian vasculature, the researcher said, an important development since neo-angiogenesis is one of the earlier events in ovarian carcinogenesis.

Several parameters differentiated normal from malignant ovaries: faster achievement of peak intensity after injecting the contrast medium, slower washout, and greater area under the receiver-operator curve.

Dr. Barua's team found that tumors contained higher levels of vascular endothelial growth factor and alpha-V-beta-3 integrins, a mediator of anchorage-independent tumor growth, than did ovaries of normal hens.

Perhaps more significantly, they detected antitumor antibodies in serum before new ovarian tumor blood vessels were apparent on ultrasound.

Dr. Barua expects that the hen model will help delineate the mechanisms underlying ovarian carcinogenesis and allow for preclinical testing of targeted therapies.

Source: Reuters Health

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