Secondary Tumour - GCSE Biology Definition

A secondary tumour is a tumour that forms when cancer cells spread from the original (primary) tumour to another part of the body. This happens through a process called metastasis, where cancer cells travel in the bloodstream or lymphatic system and begin growing in a new location, such as the lungs, liver, or bones. Although the secondary tumour grows in a different organ, it is made of the same type of cancer cells as the primary tumour. Understanding secondary tumours is important for learning how cancer spreads in the body.