Depending on the location of the tumor and other factors, doctors use different tests to diagnose neuroblastoma. Often these texts include x-rays or other imaging, like CT scans or MRIs, to determine the location and size of the neuroblastoma tumor. In about 90% of neuroblastoma cases, tumor cells produce elevated levels of hormones. The hormones are broken down by the body into acids called HVA and VMA, which are eliminated from the body in the urine. To diagnose neuroblastoma, your child may need to give a urine sample to evaluate HVA and VMA levels. High HVA to VMA ratio may indicate an undifferentiated, unfavorable tumor whereas a high VMA level may represent a more differentiated, less aggressive tumor. In addition, a complete blood count (CBC) and chemistry panel will give more information about kidney and liver function.
Once doctors have located the tumor, they take a biopsy to confirm the diagnosis and to develop the best treatment plan. Doctors will perform surgery to remove either part or the entirety of the tumor. Following surgery, a healthcare team will identify the exact type of tumor and its particular characteristics. These factors are important in determining the best treatment for your child. In some children, neuroblastoma will have spread to the bone marrow by the time of diagnosis. To evaluate your child, the healthcare team will perform a bone marrow aspirate and a bone marrow biopsy on both hips.
Determining Treatment and Risk of Relapse
After your child undergoes testing to identify the extent of tumor present and to learn about the biology or characteristics of the tumor cells, the information gathered will determine the likelihood of a recurrence of disease after treatment. Neuroblastoma is classified as low-, intermediate- or high-risk disease. The risk of relapse of neuroblastoma tumor is determined by the biology of the cancer cells, rather than when the diagnosis is made.
Currently, tumors are categorized by two different systems, the International Neuroblastoma Staging System (INSS) and the newer International Neuroblastoma Risk Group (INRG).
Understanding the risk for relapse is important because there are large differences between the treatments for low-risk, intermediate-risk and high-risk disease. In general, high-risk neuroblastomas are more likely to come back and therefore require stronger treatment than low- or intermediate-risk disease. Stronger treatment selected for high-risk disease has been shown to benefit patients; however, it also has more side effects. Therefore, risk assessment is an essential step in determining appropriate treatment.
International teams of neuroblastoma specialists have developed current treatment plans over several decades to carefully balance the benefits and risks of treatment and the chance that treatment will not be successful. Once your doctor has completed all the necessary tests and has assigned a risk category for your child, focus your attention on that particular risk group’s treatment section.