Improving the accuracy of cancer diagnoses

Tiny calcium deposits can be a tell-tale sign of breast cancer. However, in the majority of cases these microcalcifications signal a benign condition. A new diagnostic procedure developed at MIT and Case Western Reserve University (CWRU) could help doctors more accurately distinguish between cancerous and non-cancerous cases.

When microcalcifications are spotted through mammography, doctors perform a follow-up biopsy to remove the suspicious tissue and test it for cancer. In 15 to 25 per cent of cases, however, they are unable to retrieve the tissue that contains the calcium deposits, leading to an inconclusive diagnosis. The patient then has to undergo a much more invasive surgical procedure.

The new method, which uses a special type of spectroscopy to locate microcalcifications during the biopsy, could dramatically reduce the rate of inconclusive diagnosis, according to the researchers.

In a study appearing in the Proceedings of the National Academy of Sciences the week of 24 December, they found that the spectroscopy technique had a success rate of 97 per cent.

In addition, the spectroscopic approach could easily be integrated into the current biopsy procedure, says Ishan Barman, an MIT post-doc and one of the paper's lead authors. MIT post-docs Jaqueline Soares and Narahara Chari Dingari are also lead authors; senior authors are Maryann Fitzmaurice, senior research associate and adjunct associate professor of pathology and oncology at CWRU, and Ramachandra Rao Dasari, associate director of MIT's Laser Biomedical Research Center (LBRC).

'An arduous procedure'
Microcalcifications form when calcium from the bloodstream is deposited onto degraded proteins and lipids left behind by injured and dying cells. Though often seen in breast tumours, microcalcifications are rarely found in other types of cancer, Fitzmaurice says. Calcification also plays a major role in the hardening of the arteries seen in atherosclerosis.