In breast cancer and skin cancer studies presented during the RSNA conference, doctors used elastography to measure the stiffness of a suspected tumor or lesion then compared it against the consistency of surrounding tissue to determine whether the growth was likely to be cancerous and in need of biopsy. If the suspected growth fell below a particular elasticity-to-stiffness ratio, doctors predicted it was not likely cancerous. In both studies those estimates were checked against actual biopsies of the growths.
Researchers said they found the elastography-based predictions to be highly accurate. In the skin cancer study, conducted at the University of Maryland School of Medicine, Baltimore, researchers found the technique to be 100% accurate in distinguishing between malignant and nonmalignant lesions. In the breast cancer study, conducted at the University of Rochester School of Medicine, elastography proved 98% accurate in identifying cancerous skin lesions.
Researchers in both studies acknowledged, however, that their samplings were small (both fewer than 200 patients) and that a body of research needs to be conducted to determine the true effectiveness of elastography. “I don't know of any study where the specificity is 100%, so I think we will want to see this technology studied in a much larger group,” said Eliot Siegel, lead researcher on the skin cancer study and vice chairman of the radiology department at University of Maryland Medical Center.
Still, researchers agreed that the studies suggest elastography could eventually be used to rule out the need to scan biopsy tissue that initially appears to be cancerous. That could have significant implications for patients and healthcare costs since the large majority of biopsies performed in the U.S. produce benign results, said researchers.
But while the technology appears promising and is already in use for breast imaging in Europe, it still has regulatory hurdles to overcome in the U.S., said imaging equipment developers. For one thing, clinicians will need to develop and agree on elasticity ratios that can be reliably used to predict malignancies, said Natalie Benningfield, marketing manager for Philips, one of the imaging vendors pushing for the technology's U.S. approval. Philips currently has a 510K application pending with the Food and Drug administration for approval of its elastography technology to be used in breast imaging.
Several other large imaging manufactures also have elastography technology they plan to introduce to the U.S. market. G.E. Healthcare, for example, recently received FDA approval for MRI-based elastography software for use in distinguishing between types of liver tumors and lesions.
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