Tests
1st tests to order
CXR
Test
CXR is appropriate for initial imaging, but it is typically more useful in the differential diagnosis.[43]
Guidelines recommend CXR for patients with relevant symptoms and signs (e.g., dyspnea, chest pain, and weight loss).[43][44][45][46]
CXR visualizes the pleura poorly, will miss subtle abnormalities, and does not assess the mediastinal lymph nodes.[43]
Result
unilateral pleural effusion, irregular pleural thickening, reduced lung volumes, and/or parenchymal changes related to asbestos exposure (e.g., lower zone linear interstitial fibrosis)
CT chest and upper abdomen (with contrast)
Test
If clinical suspicion is high, CT scan with IV contrast should be obtained. CT with contrast is more sensitive than CXR or CT without contrast, and provides greater detail of the pleura, lungs, and mediastinum.[43][44][47][48]
Differentiating benign from malignant pleural abnormalities with CT alone is not reliable.[Figure caption and citation for the preceding image starts]: Computed tomography scan of the lung showing a right-sided pleural mesothelioma and left-sided calcified pleural plaqueFrom the collection of Dr Chris R. Kelsey; used with permission [Citation ends].
[Figure caption and citation for the preceding image starts]: Computed tomography scan of the mediastinum showing a right-sided pleural mesothelioma and left-sided calcified pleural plaqueFrom the collection of Dr Chris R. Kelsey; used with permission [Citation ends].
Result
pleural thickening and/or discrete pleural plaques, pleural and/or pericardial effusions; enlarged hilar and/or mediastinal lymph nodes; chest wall invasion and/or spread along needle tracts can occur
Tests to consider
thoracentesis
Test
The sensitivity of cytology for mesothelioma is relatively low and typically requires further pathologic assessments.[50]
Video demonstrating how to perform a pleural aspiration
Result
exudate; may show malignant cells within the pleural fluid
pleural biopsy
Test
Cytology of pleural fluid obtained via transthoracic needle aspiration biopsy (typically using CT guidance) facilitates pathologic confirmation of malignancy. This is not, however, as reliable for diagnosis as a tissue core specimen.
Pleural biopsies performed during video-assisted thoracoscopic surgery (VATS) exploration are recommended.[45][47] Biopsy three distant sites when possible.[45]
Result
specimen for pathologic diagnosis
video-assisted thoracoscopic surgery (VATS)
immunohistochemistry
Test
Recommended for all primary diagnoses.[44][47]
Studies should use selected markers expected to be positive in mesothelioma (i.e., calretinin, cytokeratin 5/6, D2-40, and nuclear WT1), and markers expected to be negative in mesothelioma (i.e., carcinoembryonic antigen [CEA], claudin 4, and thyroid transcription factor-1 [TTF-1]).[2][51][52]
Other markers can also be used to help exclude differential diagnoses.[47]
Result
positive results for certain markers (i.e., calretinin, cytokeratin 5/6, D2-40, and nuclear WT1) make mesothelioma more likely; positive results for other markers (i.e., CEA, claudin 4, TTF-1) make mesothelioma less likely
chest MRI
Test
Not recommended for initial imaging, but often used to resolve ambiguous findings on CT.[43][49] MRI can differentiate between benign fibrous mesothelioma (low signal intensity on T2-weighted images) and malignant mesothelioma (high signal intensity).
MRI is not as reliable as biopsy and will seldom alter management.
Result
degree of tumor extension, especially to the chest wall and diaphragm
fluorodeoxyglucose (FDG) PET/CT scan
Test
FDG-PET/CT can distinguish benign pleural abnormalities from malignant processes.[56]
When performed from the skull base to upper thighs, FDG-PET/CT can help define the extent of intrathoracic and mediastinal disease and can detect any regional or distant metastases.[43][47][Figure caption and citation for the preceding image starts]: Positron emission tomography scan showing hypermetabolic right-sided pleural mesotheliomaFrom the collection of Dr Chris R. Kelsey; used with permission [Citation ends].
FDG-PET/CT is used to stage mesothelioma and pleural metastases.[43]
Result
further evaluates location and extent of primary tumor; evaluates for distant metastases
cervical mediastinoscopy
Test
Mediastinoscopy, especially in patients with abnormal lymph nodes on CT scan or PET, should be considered before surgery.
Mediastinal (N2) lymph node involvement is a poor prognostic factor; these patients are not ideal candidates for aggressive multimodality therapy.[57]
Result
spread to mediastinal lymph nodes
pulmonary function tests
Test
FEV1 and diffusion capacity of lung for carbon monoxide (DLCO) should be performed on all patients with mesothelioma who are being evaluated for surgery. Patients with marginal function can be further assessed with radionuclide studies as needed.
In general, postoperative FEV1 and DLCO should be >40% of predicted values.
Spirometry is a sensitive predictor of postoperative complications after thoracotomy.
Result
spirometry and lung volumes
CBC
Test
Baseline blood counts are necessary before treatment is initiated or invasive procedures are performed.
Chemotherapy, and to a lesser degree radiation therapy, can decrease hematopoiesis, necessitating baseline and periodic analysis of blood counts.
Result
usually normal; low hemoglobin, high platelet count, high white blood cell count are usually found in advanced disease and are poor prognostic factors
basic metabolic panel
Test
Recommended as baseline before treatment is initiated.
Some chemotherapy agents, cisplatin in particular, can affect electrolytes and kidney function.
Result
usually normal
Emerging tests
diagnostic biomarkers
Test
Soluble mesothelin-related peptide (SMRP) levels may correlate with disease status.[2]
However, potential diagnostic biomarkers, including SMRP, cannot be used alone to confirm malignant pleural mesothelioma.[44][45][53][54]
Research into potential diagnostic and prognostic biomarkers is ongoing.
Result
positive for marker
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