Question

How does cancer spread?

Answer 1

Cancer spreads by a process called metastasis:

1. The malignant cells break away from the parent mass (the primary tumour).
2. They travel through the blood or lymph to other parts of the body, this capability of metastasis and invasiveness distinguishes malignant cells from benign tumour cells.
3. The malignant cells that survive in the blood or lymph invade adjacent body tissues and establish secondary tumours.
4. In the final stage, the secondary tumours become vascularised, a new network of blood vessels develops to supply them with nutrients for further growth.

As the cancerous cells grow rapidly, they kill the normal cells and disrupt the function of vital organs. The spread of secondary tumours is invariably fatal, which is why metastasis is the most feared property of malignant tumours.