Because the treatment of metastatic disease differs from that of the paraneoplastic syndromes, an accurate diagnosis is essential. The symptoms of the paraneoplastic syndrome are often more disabling than those of the cancer. Because some paraneoplastic disorders, such as LEMS, are treatable, the disability can be reversed in some instances. The presence of antibodies in the serum of some patients with paraneoplastic syndromes that react with antigens normally present only in the nervous system gives the neurobiologist a probe with which to examine neuron-specific proteins. Although paraneoplastic syndromes differ widely from individual to individual, there are certain general characteristics that apply to many of them.
Symptoms usually develop acutely or subacutely.
The disease usually evolves over days, weeks, or at most a few months, and then stabilizes, with the patient neither improving nor worsening beyond that time. This differs from most degenerative diseases of the nervous system, which evolve over years and are inexorably progressive. In addition, the neurologic disorder is usually severe. Although subclinical peripheral neuropathies have been reported in a significant percentage of patients with cancer, most patients with peripheral or central nervous system paraneoplastic syndromes have disabling symptomatology. Oligoclonal bands are common.