NCERT · Class 12 · Biology · Human Health and DiseasesDifferentiate between benign and malignant tumors. Why is metastasis considered the most dangerous property of malignant tumors?

Differences between benign and malignant tumors:

• Benign Tumors: They remain confined to their original location and do not spread to other body parts. They cause little damage and grow relatively slowly.
• Malignant Tumors: They consist of a mass of proliferating neoplastic cells that grow very rapidly, invade neighboring tissues, and destroy normal body cells.

Metastasis: \nMetastasis is the phenomenon where cancerous cells detach from the primary tumor mass, travel through blood or lymph, and lodge in distant tissues and organs of the body. Once lodged, these cells start forming secondary tumors. It is considered the most feared and dangerous property of malignant tumors because it makes local treatment (like surgery or localized radiation) ineffective, leading to widespread systemic failure and mortality.