Researchers Debate Surest Way to Diagnose Mesothelioma

The mesothelioma diagnosis you received from your doctor probably right then and there erased all doubt as to whether the cancer was present inside you. However, there was still a margin for error.

For quite some time now, researchers have been quietly arguing about the best way to eliminate that margin for error.

The dispute grew louder this month when the journal Chest published a letter from researchers in Italy taking exception to a study published in October from researchers in Britain.

The Brits indicated that they diagnose mesothelioma with the aid of thoracoscopy, but turn to thoracic ultrasound-guided fine-needle aspiration biopsy if the thoracoscopy results are indeterminate.

The Italians countered in their response letter that they go straight for the thoracic ultrasound-guided fine-needle aspiration biopsy every time.

“Differently, without awaiting the failure of thoracoscopy, we use…. fine-needle aspiration biopsy as a primary intervention procedure,” they wrote.

The Italians, from the University of Catania, explained that image-guided sampling of suspected mesothelioma tumors is their standard practice because it has a very high rate of success.

The researchers clarified, though, that they don’t perform ultrasound-guided fine-needle aspiration biopsy the minute a patient walks in the door with a complaint of chest pain.

The procedure is done after taking CT images of the chest, which doesn’t occur until they’ve first done a proper workup — including taking a medical history, asking questions, telling the patient to cough, and other typical steps.

The researchers made plain that they thought the Brits should view this biopsy as a tool of first resort rather than as a backup to thoracoscopy.

Ultrasound-guided fine-needle aspiration biopsy, they explained is “less traumatic and equally or more successful, with minimal discomfort for the patient.”

Mesothelioma Diagnosis Study Offers Results

The University of Catania researchers supported their position by pointing to a study they had conducted.

In that study, the Italians examined the records of 133 patients diagnosed between 2008 and 2013 with malignant pleural mesothelioma and those of an additional 801 found to have lung cancer.

Of the mesothelioma patients, 55 underwent ultrasound-guided fine-needle aspiration biopsy. In comparison, all 801 of the lung-cancer patients received that procedure.

The ultrasound machine’s transducer was equipped with a hole in the middle through which protruded a 20-gauge needle to aspirate the targeted tissue mass.

Twenty-gauge sounds beefy. And it is if you’re talking electrical wire. But in medicine, 20-gauge is a very thin diameter.

The researchers wrote that, despite its thinness, the needle allowed them to obtain good samples.

Because the needle is guided to its target by ultrasound, the researchers found collecting tissue samples easier and more satisfactory than by taking blind stabs or even relying on CT images to guide them.

The British Mesothelioma Study

The study that stirred the Italians to issue their response was authored by a research team headed by Robert J. Hallifax, M.D., of the Oxford Centre for Respiratory Medicine at Churchill Hospital in Oxford.

The British researchers wrote that, while image-guided tissue sampling is now standard practice, they preferred local anesthetic thoracoscopy because of its high diagnostic yield for mesothelioma.

They also said they were not troubled by thoracoscopy failures because those were to be expected in frail patients.

Frail patients, they explained, tend to have a great deal of pleural fluid or portions of the lungs tend to be stuck tight against the chest wall.

In their study, the Brits retrospectively analyzed 50 ultrasound-guided fine-needle aspiration biopsies conducted at their institution between 2010 and 2013. Of the 50 biopsy procedures, 13 were conducted after failed thoracoscopy.

Thirteen of the 50 biopsy specimens proved positive for malignant mesothelioma, while 34 specimens turned out to be mesothelioma in a benign state and one was mesothelioma-free.

Importantly, they found that ultrasound-guided fine-needle aspiration biopsy delivered satisfactory samples 94 percent of the time, except in the patients who had failed thoracoscopic exams.

In that latter group, satisfactory samples were obtained via ultrasound-guided fine-needle aspiration biopsy nearly 85 percent of the time.