MR Spectroscopy Spots Breast Cancer and Reduces Biopsies

Allison Gandey

October 3, 2007 — Researchers say their work is adding weight to the argument that magnetic resonance spectroscopy should be added to routine breast magnetic resonance imaging (MRI) exams. "This is very promising," lead author Lia Bartella, MD, from Memorial Sloan-Kettering Cancer Center, in New York, told Medscape Oncology. "Our results have shown that adding information from the MR spectroscopy study to the information given to the radiologist from the MRI study improved the positive predictive value of biopsy from 20% to 63%," she said. "In this group of patients, biopsy might have been avoided for 68% of lesions, and no cancers would have been missed."
The findings appear in the October issue of Radiology. Dr. Bartella says her group was not surprised by the results but pleased by what it found. "It is possible to perform breast MR spectroscopy with good specificity and sensitivity on 1.5-T magnet field strengths, even for non–mass-enhancing lesions," Dr. Bartella explained.
Proton hydrogen 1 MR spectroscopy measures the levels of choline compounds in a lesion and identifies an active tumor. In the present study, MR spectroscopy findings were defined as positive if the signal-to-noise ratio of the choline resonance peak was 2 or greater. Findings were defined as negative in all other cases. The researchers then compared MR spectroscopy results with histologic findings and performed a statistical analysis.
The investigators performed MR spectroscopy on 32 non–mass-enhancing breast lesions in 32 women aged 20 to 63 years. A total of 25 of these patients had lesions that had been labeled suspicious at MRI.
Biopsy Might Have Been Avoided in 68%, Without Missed Cancers
Positive choline findings were present in 15 of 32 lesions, including all 12 cancers, showing hydrogen 1 MR spectroscopy had a specificity of 85% and a sensitivity of 100%.
If only the lesions with positive choline findings had been biopsied, the researchers report, 17 of 25 lesions may have been spared invasive biopsies and none of the cancers would have been missed.
They conclude, "The use of breast MR spectroscopy in conjunction with MRI significantly increases the positive predictive value of MRI for detection of non–mass-enhancing lesions and decreases the number of benign-result biopsies recommended according to MRI findings."
Dr. Bartella pointed out to Medscape Oncology that her group was working with a small sample population — a major limitation of the work. The group adds that in their paper there were only 2 cases of ductal carcinoma in situ, which limited their ability to draw any conclusions about MR spectroscopy in the assessment of in situ carcinomas.
They write, "Further analysis in larger series with more ductal carcinoma in situ cases is necessary."
Radiology. 2007;245:80-87. Abstract