A paraneoplastic syndrome is a disease or symptom that is the consequence of the presence of cancer in the body, but is not due to the local presence of cancer cells. These phenomena are mediated by humoral factors (by hormones or cytokines) excreted by tumor cells or by an immune response against the tumor. Paraneoplastic syndromes are typical among middle aged to older patients and they most commonly present with cancers of the lung, breast, ovaries or lymphatic system (a lymphoma). Sometimes the symptoms of paraneoplastic syndromes show even before the diagnosis of a malignancy.
Paraneoplastic syndromes can be divided into 4 main categories:
- Mucocutaneous paraneoplastic syndromes
- Neurological paraneoplastic syndromes
- Hematological paraneoplastic syndromes
- Endocrine metabolic syndromes
- Others that may not fit into any of the above categories include:
A particularly devastating form of paraneoplastic syndromes is a group of disorders classified as paraneoplastic neurological disorders
(PNDs). These paraneoplastic disorders affect the central or peripheral nervous system and they are degenerative. Symptoms of paraneoplastic neurological disorders may include ataxia
(difficulty with walking and balance), dizziness
(rapid uncontrolled eye movements), difficulty swallowing, loss of muscle tone
, loss of fine motor coordination
, slurred speech, memory loss, vision problems, sleep disturbances, dementia
, sensory loss in the limbs.
The most common cancers associated with paraneoplastic neurological disorders are breast, ovarian and lung cancer, but many other cancers have been linked to PNDs as well.
Treatment options include:
- Therapies to eliminate the underlying cancer such as chemotherapy, radiation and surgery, and
- Therapies to reduce or slow neurological degeneration. Rapid diagnosis and treatment is critical for the patient to have the best chance of recovery. Since these disorders are relatively rare, few doctors have seen or treated PNDs. Therefore, it is important that PND patients consult with a specialist with experience in diagnosing and treating paraneoplastic neurological disorders.
The International Paraneoplastic Association
(IPA) is an organization dedicated to providing support and information to those affected by paraneoplastic neurological disorders.