To monitor progression or recurrence of a rare cancer called mesothelioma; this cancer affects the membranes that surround the lungs, heart, and abdominal cavity. Most cases of mesothelioma are associated with asbestos exposure.
Soluble Mesothelin-Related Peptides
After you have been diagnosed with mesothelioma, this test may be requested to follow response to treatment at anytime during or after treatment.
A blood sample taken from a vein in the arm.
This test measures the quantity in the blood of a small molecule called mesothelin-related peptides (SMRP). These peptides are breakdown products from proteins found in the membranes lining the cavities that surround the lungs, heart, and abdomen. Large amounts of SMRP are often seen in the blood of patients suffering from mesothelioma, and the amount of SMRP in the blood is thought to be related to the extent of the disease.
Malignant mesothelioma is a rare cancer of the membranes that cover the outside of internal organs and line body cavities, including the chest (pleural mesothelioma), abdominal cavity (peritoneal mesothelioma), and the heart (pericardial mesothelioma). Pleural mesothelioma is the most common type, accounting for 90% of all cases. Most cases of pleural mesothelioma-about 70% to 80%-arise in patients with a history of working with asbestos, especially in the shipbuilding, construction, automotive, and fireproofing industries. The disease has a long latency period, meaning that patients usually develop mesothelioma 20 to 50 years after asbestos exposure.
How is the sample collected for testing?
A blood sample is taken by needle from a vein in the arm.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
How is it used?
This test is limited to patients who have already been diagnosed with malignant mesothelioma. It is not used to diagnose the disease. This test is most often used in conjunction with imaging tests such as positron emission tomography (PET) and computed tomography (CT) to:
- determine if you are responding to treatment,
- see if the disease has spread,
- determine if the disease has returned after you have been treated.
When is it requested?
A doctor might request a series of SMRP tests to monitor progression of mesothelioma or its recurrence;
- after you have been diagnosed,
- after you have had surgery to remove tumour tissue in the chest cavity,
- during and/or after chemotherapy or radiation therapy.
What does the test result mean?
If a series of blood tests show that SMRP concentrations are increasing, it may indicate that mesothelioma has progressed. If the series of tests indicate that SMRP concentrations are decreasing, you may be responding to therapy. If the concentrations remain unchanged, it may mean that your disease has stabilised
The interpretation of your SMRP test results will likely be done in conjunction with results from imaging studies. That’s because;
- the test does not always provide doctors with useful information. Patients with other cancers - including lung, ovarian, endometrial, and pancreatic cancers - can have apparent elevated SMRP test results as a result of their cancers producing substances that interfere with the test.
- some patients with epithelial mesothelioma, a form of the disease that affects the cavity lining or membranes, do not produce SMRP.
Is there anything else I should know?
This test is not used to diagnose mesothelioma but only used to monitor progression or recurrence. The diagnosis of this disease is often difficult and involves many steps. It usually begins with a review of the patient’s medical history, including a history of exposure to asbestos, and with a complete physical examination. These may be followed by imaging studies of the chest and abdomen, including X-rays and computed tomography (CT) scans, and with lung function tests. Diagnosis may be confirmed by examining tissue from a biopsy or fluid from the affected area for malignant cells.
What is asbestos and how does it cause mesothelioma?
Asbestos is a heat- and fire-resistant insulating material that was widely used in construction, shipbuilding, and the automotive industry after 1945 through the 1970s. Workers breathed in the tiny fibres that comprise asbestos. Those fibres entered their pleura, the lining of the chest cavity and lung, and damaged its cells. Mesothelioma develops over a long period of between 15 and 40 years. Research has also shown that family members and others living with workers exposed to asbestos are at an increased risk of developing mesothelioma.