Optical mammography may offer better way to detect breast cancer

By Niharika Midha, MSc

Breast cancer remains the largest prevalent form of cancer in women and its early detection is essential to improve survival rates. To combat a disease that is the leading cause of cancer death in women, claiming an astounding 458,000 lives worldwide in 2008, we need to rely on advances in diagnostic technologies including imaging and gene testing. Despite many debates on how effective diagnosis is using mammography, it still remains the most widely used technique for the screening and detection of breast cancer. Now, with the advent of cutting-edge technologies that address the flaws with traditional mammography techniques, are we ready for a new era in breast cancer diagnostics?

A recent portable optical scanner developed by the Tufts University School of Engineering offers several promising advantages over the current gold standard – mammography. This new Tufts optical scanner would be a stand-alone device which does not need to be combined with an adjunctive modality or contrast agent, further allowing differentiation between benign and malignant tissues, unlike in mammography which is usually combined with other imaging techniques such as ultrasound for breast cancer diagnosis. In essence, such a device could possibly replace the use of mammography/ ultrasound.

The Tufts scanner lightly presses the breasts between glass plates for illumination with Near Infrared (NIR) light and scans them by using an optical system; this information is then interpreted with the help of an algorithm. Optical mammography, also known as diffuse optical imaging, measures changes in blood oxygenation and blood flow of a tissue when illuminated with NIR light. This technique is also capable of differentiating between fats and water based on varying light absorption.

Other advantages of this technique include non-invasiveness, cost effectiveness and patient comfort. Since the technique uses non-ionizing radiation, realtime detection is possible without the risk of radiation exposure and, unlike in traditional mammography, the breast tissue does not need to be greatly compressed. A five year clinical study to test the Tufts scanner’s effectiveness, funded by a $3.5m grant from the US National Institutes of Health, is currently recruiting patients.

The global mammography equipment market is expected to grow from $897.2m in 2009 to $1.2 billion by 2016. A research study conducted by the Cancer Registry of Norway in 2010 suggests that traditional mammography might not be as effective as was previously perceived. The study indicated that routine mammography only reduced breast cancer mortality by 10%, much less than the World Health Organization’s estimate of 25%. This failing, combined with the associated high number of false positive diagnoses and use of ionizing radiation (leading to a significant health risk), points to a clear unmet need for accurate and early diagnosis of this deadly disease. The new Tufts device also focuses on reducing the number of false positives and providing more specific breast screenings, explained Sergio Fantini, Professor of Biomedical Engineering at Tufts.

“The consensus is that x-ray mammography is very good at detecting lesions but it's not as good at determining which suspicious lesions are really cancer," says Fantini., who is leading the research effort. The Tufts NIR technique could complement standard mammography, particularly for women younger than 40 who may have dense breast tissue that tends to obscure detail in x-rays.

“It’s been reported that patients who respond to breast cancer chemotherapy show a decrease in hemoglobin and water concentration and an increase in lipid concentration at the cancer site,” explains Fantini. “This suggests that NIR imaging can be valuable not only in diagnosing breast cancer but in monitoring individual response to therapies without requiring repeated x-rays. For example, it could help determine if a patient is responding to neoadjuvant chemotherapy administered to shrink a tumour before surgery.”

For a new technology to be adopted, it should exhibit specificity and sensitivity that is at least as good as, if not better than, the current methodologies, while addressing the safety issues. If optical mammography succeeds at this, there is no reason why it will not be embraced rapidly by the medical community, as it clearly offers several advantages, and since the technology is comparatively cheap, the cost would not be a bar to its adoption.

 Date of upload: 22nd Jan 2013


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