Researchers in Germany say the diagnostic accuracy of lung fluid tests for mesothelioma is high enough that they can be routinely used for diagnosis.
Right now, if mesothelioma is suspected, doctors may order a fluid test first. If the fluid test (cytology) is positive, the doctor usually orders a tissue biopsy (histology) to confirm.
But the German team says their study shows that the diagnostic accuracy of cytology is almost as good as histology for mesothelioma – especially when doctors consider the patient’s hyaluronic acid level, too.
Scientists from several German institutions analyzed cytology tests from more than 4,500 suspected cases of pleural mesothelioma. They conclude that cytology is accurate enough to be used routinely for diagnosis.
The Importance of Diagnostic Accuracy with Mesothelioma
Malignant mesothelioma is a rare cancer that is not easy to diagnose. Early symptoms of pleural mesothelioma may include cough, shortness of breath, or chest tightness. People often think they have a cold or pneumonia at first.
There is no single test to tell if a person has mesothelioma. Instead, doctors usually have to use a combination of lab tests, exams, imaging studies, and patient history to make a diagnosis. Patient history is key since most mesothelioma patients have asbestos exposure in their background.
Diagnostic accuracy is especially critical with this cancer because it grows so fast. Any delay in diagnosis means a delay in treatment. Like many cancers, the earlier a mesothelioma patient receives treatment, the better.
Many cancer patients develop fluid around their lungs called pleural effusions. This fluid can contain malignant cells. If cytology testsd on pleural effusions can pinpoint mesothelioma with high enough diagnostic accuracy, it could lead to faster and earlier diagnosis.
Could Fluid Cytology Help Improve Mesothelioma Diagnosis?
The German study included 5,731 lung fluid samples from 4,552 patients with pleural effusions. Samples were collected between 2000 and 2017.
Cytological findings confirmed mesothelioma in 223 patients. Another 88 cases with negative cytology had hyaluronic acid (HA) levels over 30 mg/L. These cases also turned out to have malignant mesothelioma.
The diagnostic accuracy of cytology alone was 0.50. When doctors considered HA level too, accuracy went up to 0.70. Just as importantly, these tests were 0.99 accurate at ruling out mesothelioma in people who did not have it.
“We conclude that cytological evaluation of effusions aided by the assessment of HA demonstrates the diagnostic sensitivity and specificity for malignant mesothelioma no less than the hitherto standard histological evaluation,” writes Christian Biancosino of HELIOS University Hospital Wuppertal.
Biancosino and colleagues say cytology tests may be “routinely considered” in patients suspected of having mesothelioma. The diagnostic accuracy of the tests means they can also help confirm mesothelioma in cases where histology tests are inconclusive.
Biancosino, C, et al, “Cytological Diagnostic Procedures in Malignant Mesothelioma”, November 18, 2021, Advances in Experimental Medicine and Biology, Online ahead of print, https://doi.org/10.1007/5584_2021_680