The inability to extend or bend the index finger of the right hand is not a typical symptom of cancer. The cause of this symptom may be tenosynovitis, rheumatoid inflammation or nerve compression of the finger. 1. Tenosynovitis: The movement of the tendon in the tendon sheath is obstructed due to edema and thickening of the tendon in the tendon sheath, which in turn causes the symptom of inability to bend the finger. 2. Rheumatoid inflammation: Rheumatoid inflammation will destroy the ability to move the joints, resulting in stiffness of the joints and restriction of finger bending. 3. Nerve compression: it may be related to nerve compression, the nerve of the finger joints is damaged, resulting in a decrease in the strength of the finger flexor muscles, so that the fingers can not be freely stretched, bent and other actions. The right index finger can not be stretched or bent is not a typical symptom of cancer, but it should be taken seriously. It is recommended to go to the hospital as soon as possible to get a clear picture of the cause of the disease through electromyography and other systematic examinations, and to treat the cause of the disease under the guidance of a professional doctor. During the treatment period, patients should pay attention to rest, do not move their fingers excessively, and do not lift heavy objects.