G73: Disorders of myoneural junction and muscle in diseases classified elsewhere

G73.2: Other myasthenic syndromes in neoplastic disease

Nerves are a sort of wiring in the body. Nerves conduct information. The nerves use electrical impulses to do this. Nerves are important, for instance, in enabling you to sense contacts and temperatures, and to move your muscles.

When muscles are only receiving limited information from the nerves, the muscles get tired more quickly. As a result, some parts of the body will have less strength than usual. In your case, the muscle weakness is linked to a cancer.