Paraneoplastic syndrome

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at August 3, 2016
StartDiseasesParaneoplastic syndrome

It's been estimated that up to 50% of all people with cancer will acquire a type of paraneoplastic syndrome at some point during their illness. Paraneoplastic ("para" meaning beyond, "neoplastic" meaning tumorous) syndromes are a cluster of uncommon negative symptoms that crop up most often in older or middle-aged people who have been diagnosed with cancer.

Contents

Definition & Facts

Symptoms related to the central nervous system (neurological) are the most commonly documented symptoms of paraneoplastic syndrome, but a patient's hormones (endocrine system), skin, blood, or joints can also be affected.

Paraneoplastic syndromes generally manifest when cancer-killing substances released in the body by the immune system also destroy healthy cells in the brain, spine, nerves, or muscle tissue. The cancers most frequently connected with these syndromes include blood cancer, lung cancer, breast cancer, and ovarian cancer. Many times, paraneoplastic syndromes can develop before a formal cancer diagnosis is made.

Symptoms & Complaints

The symptoms associated with paraneoplastic syndromes normally show up rapidly over a period of days or weeks. The symptoms are variable according to the damaged body tissue and can present as difficulty walking, unsteady gait, muscle atrophy and muscle weakness, poor eye-hand coordination, trouble swallowing, slurred speech or incoherent speech, amnesia or other cognitive impairment, vision problems, insomnia or oversleeping, seizures, muscle tremors, and sudden involuntary reactions.

These types of symptoms are typically seen in groups or patterns that distinguish them as being a specific syndrome. If these particular syndromes coexist with cancerous tumors in the body, they're defined as paraneoplastic syndromes. These syndromes are also theorized to contribute to some of the most prevalent cancer symptoms, which includes low energy, loss of appetite, and unexplained weight loss.

Comparable symptoms can also occur due to an immune system condition that isn't connected with cancer. Consequently, neurological symptoms are recognized as being paraneoplastic syndromes only if they've been proven to be related to cancer. 

Causes

Paraneoplastic syndromes are caused not by the direct interference of cancerous cells with neurological functions but by the body's immune system processes. Studies have indicated that paraneoplastic syndromes result from the immune system's response to cancer, which releases large amounts of protective antibodies and white blood cells known as T cells into the bloodstream. In addition to targeting the cancerous cells, these immune system compounds also destroy the body's healthy cells and create one or several paraneoplastic conditions.

Cancerous cells can spread out or metastasize from their original location to other body areas, like in cases where cancerous cells migrate from the lungs to the brain or heart. This can make the causes of paraneoplastic syndromes difficult to pinpoint due to the fact that they may exist in parts of the body that are nowhere near the specific area affected by cancer.

Other neurological disorders can be caused by cancers of the brain or spine, while non-neurological body cancers may cause physical tissue damage that harms the CNS by impinging on nerves.

Diagnosis & Tests

To properly evaluate neurological issues that could lead to the diagnosis of paraneoplastic syndrome, physicians perform a basic physical examination and neurological examination. They ask certain questions and carry out standard assessments in their clinic or hospital to test a patient's reflexes, muscle definition and muscle strength, hearing, vision, dexterity and balance, cognition, and behavioral patterns.

Lab analyses identify levels of antibodies, infections, hormones, or metabolic function in the body that are often linked to paraneoplastic syndromes. These tests typically include blood tests and clinical urine tests, spinal taps, computerized tomography (CT) scans, magnetic resonance imaging (MRI) scans, and positron emission tomography (PET) scans.

If a cancerous tumor cannot be found, it still may exist but be too small to detect while the body's immune system response is keeping it contained. Some patients will need to complete additional imaging tests every few months before the reason for their condition is pinpointed.

Treatment & Therapy

Treating a patient with paraneoplastic syndrome goes hand-in-hand with treating the cancer itself, and may include slowing the immune system response that's responsible for the adverse neurological symptoms. A treatment plan must be developed that's appropriate for the particular kind of paraneoplastic syndrome a person has. In combination with chemotherapy drugs to destroy any existing cancer, a physician can prescribe a number of different drugs to limit the tissue damage caused by an overactive immune system.

Corticosteroids like prednisone help to lessen inflammation in the body. Unfortunately, some of the potential long-term complications of steroids are diabetes mellitus, osteoporosis, hypertension, and high cholesterol levels, among others. Immunosuppressant drugs like azathioprine and cyclophosphamide help slow down the body's release of cancer-battling white blood cells, but a negative side effect of these medications is an increased vulnerability to bacterial infections.

Based on the specific kind of paraneoplastic syndrome that's diagnosed, other treatments might include epileptic drugs to help manage the recurrence of seizures that may develop due to a chemical imbalance in the brain. Medicines that improve transmissions between the nerves and muscles can potentially help with paraneoplastic syndromes that impact muscle strength. For instance, a medication like 3,4-Diaminopyridine boosts the body's output of neurotransmitters, which are chemicals that enable communication between nerve tissue and muscle cells. Other medications like pyridostigmine improve muscle function by improving nerve impulses.

Other treatments that may improve symptoms include plasmapheresis, IVIG (intravenous immunoglobulin), physical therapy to help regain muscle control, and speech therapy if the patient has difficulty talking or swallowing.

Prevention & Prophylaxis

A number of different pharmacological substances may be prescribed for the prevention and prophylaxis of paraneoplastic syndrome. Frequently used pharmaceuticals of this type are blood thinners like UFH (unfractionated heparin), LMWHs (low molecular weight heparins), and warfarin.

Patients with cancer, particularly those with breast cancer, who have just had a major surgical operation, who are having chemotherapy, or who have catheter implants - are usually prescribed warfarin for the prophylaxis of paraneoplastic syndrome. Common non-drug options for prophylaxis are pneumatic compression garments or boots and elastic hosiery.