ARRS 2009: Breast Elastography Accurately Diagnoses Malignancies

Alice McCarthy

April 30, 2009

April 30, 2009 (Boston, Massachusetts) — In a study comparing ultrasound with breast elastography measurement, researchers found that breast elastography was highly effective in distinguishing benign from malignant breast masses. All malignant masses in the study were diagnosed by elastography compared with 88.5% by routine ultrasound.

The study was presented here yesterday at the American Roentgen Ray Society (ARRS) 2009 Annual Meeting.

Elastography is a technique looking at the mechanical properties of tissues (relative stiffness) as opposed to conventional ultrasound, which looks at the backscatter of transmitted ultrasound waves through tissues.

"Breast radiologists like myself understand that breast ultrasound is sensitive but not specific," lead study investigator Llewelyn Sim, MD, from Singapore General Hospital, told Medscape Radiology. "You can detect lots of breast lumps with ultrasound, but few of them eventually turn out to be cancer. Hence, I wanted to prove through this study that elastography improves the specificity of ultrasound so that we only detect breast lesions that matter (namely cancers) and reduce work-up, unnecessary biopsies, and patient anxiety."

The study at Singapore General Hospital in 99 women evaluated 110 sonographically visible breast lesions using a sonogram system outfitted with breast elastography measurement capability. Twenty-six malignant masses were noted; 84 were benign. All lesions were evaluated with ultrasound, elastography, and combined ultrasound/elastography. All women were referred for breast biopsy for confirmation of findings.

Based on histology reports, ultrasound alone correctly diagnosed 42.9% of the lesions in the study. This figure increased significantly to 76.2% with elastography alone. And the specificity of the combined technique rose a bit more to 81% of the cases. Elastography detected all malignant masses in the study (n = 26) compared with 88.5% by routine ultrasound.

Breast Mass Elasticity Measured

"In my practice currently, when I am doing a breast ultrasound and wonder how I should categorize a breast mass, I turn on the elastogram, which is an added feature on the machine like Doppler, to look at the elastic property of the tissue," Dr. Sim said. "Hard lesions will be more suspicious of cancer, softer lesions are more likely benign. That information would then help me make a decision whether to follow the lesion for a period of time or refer for breast biopsy immediately."

Dr. Sim said the technique helps him decide how to assign a Breast Imaging Reporting and Data System (BIRADS) score to the lesion. "I would use it when I am unsure of categorizing a BIRADS 4, 3, or 2 lesion," he explained. Scores of BIRADS 3 (probably benign) and 4 (suspicious abnormality) require follow-up. In contrast, BIRADS 2 lesions are definite benign lesions necessitating only routine screening.

In retrospect, Dr. Sim said that two thirds of the women in the study could have avoided biopsy based on the ultrasound/elastogram analysis. "All of the women still had biopsy because this technique is still in its infancy," he said. "But I foresee breast elastography will be another parameter, like Doppler, where you can switch it on and off and analyze the lesion while doing the ultrasound examination." The additional measurement adds about 2 to 3 minutes to the ultrasound examination.

"Breast elastography is an interesting approach, but it is only a research tool now in the United States," session moderator Alexis Nees, MD, a diagnostic radiologist at the University of Michigan Medical School, Ann Arbor, told Medscape Radiology. "It does seem to have some promise in helping to differentiate potentially benign from malignant lesions."

Dr. Nees said the patient population most likely to receive an elastogram measurement at ultrasound would be those categorized with BIRADS 4 or 5 (highly suspicious of malignancy) lesion. "There is more work to be done before we would know," she said. "I do not think it will replace conventional ultrasound but might be utilized as a tool in addition to help diagnosis."

Systems Not Standardized

But systems variations still remain to be addressed before the medical accuracy of the technique can be evaluated fully. "I believe we have to overcome physicians' impression of breast elastography from earlier systems that used different technology and did not perform to clinical expectations," Dr. Sim said. "All of the elastogram/ultrasound systems available use different ways and techniques of measuring the lesion elasticity."

The research by Dr. Sims used a novel method of elastography with the aim of changing lingering impressions. "With the sterling results and knowledge gained from my study, I am more confident in using elastography to assist me in obtaining a more accurate diagnosis of breast lesions detected with ultrasound in my daily clinical practice," he said.

The study did not receive commercial support. Dr. Sims and Dr. Nees have disclosed no relevant financial relationships.

American Roentgen Ray Society (ARRS) 2009 Annual Meeting: Abstract 119. Presented April 29, 2009.

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