Rather than relying on MRI and follow-up biopsy to provide information about a suspect abnormality in the breast, researchers at the Memorial Sloan-Kettering Cancer Center in New York have demonstrated in preliminary trials that NMR spectroscopy could be used to significantly reduce the number of biopsies required to detect the early stages of breast cancer. NMR can lock on to the choline peak associated with malignancy during the MRI scan.

Lead researcher Lia Bartella MD and her colleagues found that NMR could reduce the need for biopsy by 58%. They demonstrated that 23 of 40 suspicious lesions could have been spared biopsy, and none of the resultant cancers would have been missed, in a study group. "All cancers in this study were identified with MR spectroscopy," explains Bartella, "There were no false-negative results. These results should encourage more women to take this potentially life-saving test."

MRI is an increasingly useful tool in screening women at high risk of developing breast cancer. However, the technology in its current form has a major drawback in that it often produces suspect images that require surgical biopsy but that once tested are found to be benign. By coupling NMR to MRI, the radiologist is not only able to see any suspicious lesions but can obtain a chemical profile of a putative tumour. In most cases, this precludes the need for a biopsy when the NMR does not produce results characteristic of malignant, or cancerous, tissue.

"Breast tumours have elevated levels of choline compounds, which are a marker of an active tumour," Bartella explains, "By performing a brief MR spectroscopy procedure after an MRI scan, which takes only 10 additional minutes, we can non-invasively see which tumours show elevated choline levels, and therefore which lesions are likely malignant. This could eliminate the need for biopsy."

In the study, 56 patients with 57 breast lesions first underwent MRI, followed by NMR. Biopsy was performed after imaging, and results were compared. The team found 31 malignant lesions at biopsy and 26 benign lesions. All 31 malignant lesions were diagnosed correctly with NMR, giving NMR a sensitivity of 100%, and 23 of 26 benign lesions were diagnosed correctly (giving NMR 88% specificity).

The remaining three benign lesions had elevated choline levels, and the researchers are still exploring why certain types of benign lesions should display raised choline levels, despite being non-malignant status.

"MR spectroscopy is fast and well tolerated, and could be readily incorporated into a breast MRI examination," adds Bartella, "By reducing the number of benign biopsies recommended at MRI, the use of MR spectroscopy will not only reduce patient morbidity, but will save unnecessary anxiety, cost and time for both the patient and the medical staff."

Related links:

• Radiology, 2006, 239, 686-692
• Bartella's Page

Article by David Bradley