An Introduction to Paraneoplastic Neurological Disorders
What are paraneoplastic neurological disorders?
Paraneoplastic neurological disorders (PND's) are autoimmune diseases that occur in response to the presence of cancer somewhere in the body. The cancer cells in paraneoplastic patients express proteins which are normally only made in the brain. These proteins cause the body's immune system to produce antibodies in an attempt to suppress the cancer. Unfortunately, these same antibodies can trigger an autoimmune attack on the brain and the body's neurological systems. Doctors are not yet sure why the immune system reacts the way it does in some patients with cancer, but not in others.
What types of cancers are most commonly associated with paraneoplastic disorders?
Breast, ovarian and lung tumors are the most common cancers to be associated with PND's. However, cases of paraneoplastic neurological disorders have also been found in patients with other forms of cancer, including lymphomas, testicular cancer, childhood brain tumors and cancer of the larynx. In about two-thirds of patients, the neurological symptoms of PNDs begin before cancer is found.
Is cancer always found in paraneoplastic patients?
No. It is entirely possible to have the neurological symptoms and antibodies associated with a PND and not have any identifiable cancer.
Some doctors theorize that this is because the proteins associated with PNDs act as a natural anti-tumor weapon, thus preventing the cancer from growing large enough to be found.
Are there different types of paraneoplastic neurological disorders?
Yes. There are a number of different antibodies and autoimmune reactions that are classified as PND's. The most common PND's include Paraneoplastic Cerebellar Degeneration (PCD), Opsoclonus-Myoclonus Syndrome (OMS), Eaton-Lambert Syndrome, and Paraneoplastic Limbic Encephalitis (PLE). There are others as well. Symptoms and treatment options can vary depending on the type of PND and the underlying auto bodies involved.
What are the most common initial symptoms?
Difficulty with walking, balance, or speech; hand tremors; memory and mood disturbances; lack of coordination; weakness. These symptoms may begin suddenly or may be gradual.
How are PNDs diagnosed?
For the most common paraneoplastic syndromes, diagnosis is usually made by a blood test which looks for common antibodies associated with the syndromes. The main provider of this diagnostic test is Athena Diagnostics. Athena Diagnostics offers the test for both U.S. and international patients. In more difficult cases, however, PET scans, spinal taps, and other diagnostic methods may be used.
What is the life expectancy for someone who has been diagnosed with a paraneoplastic disorder?
It is impossible to give an average life expectancy for paraneoplastic patients. Many variables can affect how long a patient with PND will survive including their age, the type of underlying cancer, the type of PND, the success of cancer treatments, and other pre-existing health conditions. Several small scale research studies have indicated an average life expectancy of between two and three years.
Although the International Paraneoplastic Association does not keep formal records, we have noted a wide variety in the life spans of the hundreds of paraneoplastic patients who have contacted us. Some patients deteriorate very quickly and pass away within months of the beginning of neurological symptoms. Others live for 3, 4, or 5 years. We have been in touch with paraneoplastic patients who survived for 10 years or more, and have at least one report of a paraneoplastic patient who lived for 35 years after neurological symptoms began.
Do paraneoplastic patients ever fully recover?
Very rarely. Of the hundreds of patients who have been in touch with the IPA, we know of only two patients who fully recovered after successful cancer treatment.
However, many patients find they stabilize with proper treatment and may even show some small but gradual improvement over a period of months. Early treatment before severe neurological damage occurs is key.
Do all paraneoplastic patients end up in nursing homes?
No. While many patients will need some form of assisted care, many manage to remain at home with the assistance of loved ones.
Are there any good articles that can help me understand paraneoplastic neurological syndromes better?
For a very good overview of the different types of paraneoplastic disorders, I recommend Managing Paraneoplastic Neurological Disorders, from the March, 2006, issue of The Oncologist. Although written for medical professionals, it is easily understandable by most lay-persons as well.