Screening to detect breast cancer early may become a reality if thermography (thermal imaging) that is in the early stages of testing is perfected. The trial is jointly done by the Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam and the Chennai based Sri Ramachandra Medical College (SRMC).
Thermography detects infrared radiation emitted by a body, and the wavelength of the infrared radiation is correlated to the temperature.
“Any cancerous/abnormal cells will cause increased blood flow. Increased blood flow results in increased temperature. Thermogrpahy looks for such increase in temperature in any part of the breast,” said Dr. B. Venkatraman, Head, Quality Assurance Division at IGCAR.
However, not all cells that exhibit an increased temperature due to increased blood flow are cancerous. Hence its ability to identify all cancerous cells and only the cancerous cells is crucial.
The performance and ability of thermography to detect breast cancer were first tested on 25 patients who had come to the Department of Atomic Energy Hospital at Kalpakkam with pain/indication of breast cancer.
The clinical standardisation (determining the ambient temperature at which the screening should be done etc) has already been done at SRMC.
Results from thermography were compared with mammography and tissue biopsy in nearly 200 patients. Patients above the age of 40 and who complained of pain in the breast were chosen.
“The sensitivity is about 98 per cent (ability to detect positive cases) and the specificity (ability to pick up only the positive cases) is 88-90 per cent,” said Dr. P. Surendran, Associate Professor in General Surgery, SRMC. The sensitivity and specificity were derived during the process of clinical standardisation.
According to him, the specificity is as high as 96 per cent in well established breast cancers and about 85 per cent in the case of early lesions (about 1 cm size).
Following the clinical standardisation, thermography has been used on 60 patients at SRMC. The analytical standardisation — to know which cells/areas exhibiting abnormal temperature are actually cancerous — is in progress. Analytical standardisation would help provide accurate information of the sensitivity and specificity.
“What we have done now is to see if thermography can be more sensitive than mammography, so we can pick up cases at a much earlier stage and confirm it with mammography and tissue biopsy,” said Dr. S.P. Thiagarajan, Director of Medical Research at Ramachandra University.
It will be an ideal and a superior tool for screening compared with mammography if the specificity is also high. For instance, unlike mammography, thermography detects breast cancer non-invasively.
There are several other advantages as well. Patients are not subjected to any radiation, it is not expensive, is a painless procedure, and can be done quickly.
But the most important advantage is that thermography can pick up cancerous/abnormal cells immaterial of the age of patient and the type of breast. “Mammography cannot pick up smaller lesions in younger patients [less than 40 years] and when the breast density is high. That is its biggest disadvantage,” said Dr. Surendran. “Mammography is useful in older patients and smaller breasts.”
“Our aim is to perfect it so we can use it as a screening tool in rural settings,” said Dr. Baldev Raj, Director of IGCAR. It is, however, too early to say that thermography can be used as a screening tool. But it will surely turn out to be an invaluable tool if the specificity issue is addressed.