Typically most cases of cancer of the arm are metastasis from another site, and very common is from breast cancer to under the arm.

The first signs of Arm cancer is usually Pain. It may be intermittent initially. If you are having pain in your arm and you are suffering or could be suffering from Cancer, you need to act fast to do something about it. Cancerous bones can break or fracture very readily if they are not fixed. I suggest you read some of the stories here to see how it can affect you and what they did about it.