Cancer

Whether a tumor is benign or malignant determines how potentially life-threatening it is. Benign tumors are usually harmless, although their location may be serious (if surgery to remove the tumor would carry significant risk). These tumors are not considered cancerous, are relatively slow-growing, and usually are encased within a fibrous capsule.

Malignant tumors (cancers) have great potential to spread, or metastasize, to other sites in the body. These tumors are fast-growing and aggressive, and they invade neighboring healthy tissue. They therefore are considered life threatening.