Using the free-floating cancer cells present in lung-fluid to diagnose malignant mesothelioma may lead to earlier detection and better outcomes.
That is the conclusion of cancer researchers at Stockholm’s Karolinska University Hospital.
The team’s goal was to evaluate the established criteria for cytopathological diagnosis of mesothelioma, i.e. diagnosis using cells found in fluid (effusions) instead of cells from a tissue biopsy.
In a newly published article in the Archives of Pathological and Laboratory Medicine, the researchers observe, “Despite the difficulties in recognizing malignant cells present in those early effusions, they are often the first available biologic material for diagnosis.”
Diagnosing Pleural Mesothelioma
Malignant pleural mesothelioma, a rare but fast-growing cancer associated with asbestos exposure, is notoriously difficult to diagnose.
Diagnosis usually involves a combination of modalities, including examination of tumor cells under a microscope, scans such as CT or PET, a physical exam, an analysis of mesothelioma biomarkers in blood or lung fluid, and a thorough work history.
For most patients, by the time these tests are being done, their mesothelioma is already in an advanced stage when even aggressive treatments are less likely to be effective.
The Karolinska University researchers say looking for mesothelioma cells in early pleural effusions (lung fluid) may allow doctors to detect mesothelioma earlier than they can with other tests – as long as the evaluation criteria itself is valid.
Testing the Mesothelioma Diagnostic Criteria
To determine how useful the current cytological evaluation criteria are, the researchers reviewed the cases of 85 malignant mesothelioma patients diagnosed at their hospital between 2004 and 2013.
They concluded that, using these criteria, not only could lung fluid be used to make a mesothelioma diagnosis with “high positive predictive value”, but that such a diagnosis also had the potential to result in better mesothelioma outcomes.
“With the earlier diagnosis obtained by cytology, a better effect of chemotherapy can be expected, as shown by the longer overall survival in these patients compared with those with a histopathologic diagnosis,” concludes lead author Anders Hjerpe, MD, PhD.
The researchers say combining cytological tests with other diagnostic modalities improves the likelihood of making an accurate earlier mesothelioma diagnosis.
Right now, many of the 2,500 or so mesothelioma patients diagnosed in the US each year succumb to the disease within 12 to 18 months, even with the most advanced cancer treatments.
Hjerpe, A, et al, “Cytopathologic Diagnosis of Epithelioid and Mixed-Type Malignant Mesothelioma: Ten Years of Clinical Experience in Relation to International Guidelines”, August 2019, Archives of Pathological and Laboratory Medicine, pp. 893-901