A recent study in Japan may have revealed a new method for diagnosing mesothelioma.
Mesothelioma is the cancer of the thin lining that surrounds the lungs, heart, and stomach. The disease is rare and very difficult to diagnose, in part because it has a long latency period – typically from 20 to 50 years – and in part because mesothelioma symptoms are often indistinguishable from other diseases of the lungs such as emphysema, bronchitis and chronic obstructive pulmonary disease (COPD).
Traditional diagnostic techniques involve extracting and analyzing fluids from the pleural cavity – the thin, fluid-filled space that surrounds the lungs. To confirm the presence or absence of malignant mesothelioma, this procedure is usually followed by a biopsy.
The biopsy is performed by inserting a tube called a thoracoscope into the chest between two ribs. The thoracoscope has an eyepiece, which allows the doctor to see the inside the pleural cavity, and can have various tools attached at its end. These tools are used for collecting tissue samples for lab work and testing. Most commonly, standard flexible forceps (SFF) are used to cut off a small piece of suspected cancerous tissue. The size of this piece is sometimes too small to perform accurate tests on.
The study’s authors, Shinji Sasada and colleagues in Osaka, studied 20 cases of undiagnosed pleural effusion – a condition where excess fluid fills the pleural cavity and puts uncomfortable and sometimes painful pressure on the lungs. Pleural effusion can be caused by many conditions, including tuberculosis, breast cancer, and malignant mesothelioma – all of which can be diagnosed with biopsies. Instead of performing the biopsies with SFF, the team in Japan used a special kind of knife, called an insulated-tip diathermic knife (IT knife), that uses heat to cauterize a large piece of the diseased tissue.
The IT knife was found to have a diagnostic yield of 85%. Compared to the 60% diagnostic yield of SFF, this means that the IT knife was more likely to provide the information needed to establish a diagnosis. Additionally, the IT knife biopsy was superior to SFF in eight of the 20 cases – three of which had malignant pleural mesothelioma.
The IT knife biopsy was performed in minimal time with no severe complications, indicating that this technique may be a viable method for diagnosing mesothelioma.