Decisions about screening tests can be difficult. Not all screening tests are helpful and most have risks. Before having any screening test, you may want to discuss the test with your doctor. It is important to know the risks of the test and whether it has been proven to reduce the risk of dying from cancer.
When a screening test result leads to the diagnosis and treatment of a disease that may never have caused symptoms or become life-threatening, it is called overdiagnosis. For example, when a urine test result shows a higher than normal amount of homovanillic acid (HMA) or vanillyl mandelic acid (VMA), tests and treatments for neuroblastoma are likely to be done, but may not be needed. At this time, it is not possible to know which neuroblastomas found by a screening test will cause symptoms and which neuroblastomas will not. Diagnostic tests (such as biopsies) and cancer treatments (such as surgery, radiation therapy, and chemotherapy) can have serious risks, including physical and emotional problems.
Screening test results may appear to be normal even though neuroblastoma is present. A person who receives a false-negative test result (one that shows there is no cancer when there really is) may delay seeking medical care even if there are symptoms.
Screening test results may appear to be abnormal even though no cancer is present. A false-positive test result (one that shows there is cancer when there really isn't) can cause anxiety and is usually followed by more tests and procedures, which also have risks.