A tumour is a mass of cells. Benign tumours don’t spread into nearby tissue, which means they aren’t cancerous. Malignant or invasive tumours, on the other hand, spread into nearby tissue, multiplying and pushing out healthy cells.
When cancer cells break off a tumour and travel to another parts of the body through the blood or lymphatic system, forming new tumors, that’s called metastasis. When you hear that someone’s cancer has metastasized, it means it has spread beyond the original site. So for example, if someone has breast cancer and the cancer spreads to the bone, it’s referred to as bone metastases.
That’s why it’s important to find cancer as early as possible – when tumours are smaller, they are easier to treat, and there’s less chance that the cancer has spread.
However, not all cancers form solid tumours. Blood cancers like leukemia don’t often form lumps, and because they are in the blood and bone marrow, they can spread quickly before being diagnosed.
Find out more about tumours here.
