Monthly Archives: August 2015

When Cancer Spreads: Understanding Metastasis

By Louise Chang, MD

How does lung cancer reach other areas of my body? Why did breast cancer show up in my bones? What does it mean to have metastatic cancer?

It can be hard to understand how cancer starts in one place and also shows up in other places in the body that are far from where it started. The ability to spread, called metastasis, speaks to the aggressive nature of cancer and the challenge it poses.

Cancer starts from cells in our body that have gone rogue. The body has ways to monitor and dispose of abnormal cells that develop, but cancer cells are able to avoid the body’s defense system. They grow out of control and form into cancerous tumors.

As cancer cells multiply, they can get into the bloodstream and lymph system. This allows the cancer cells to travel and settle in other parts of the body. When cancer spreads like this, it is described as “metastatic” – because cancer cells have moved to a different location in the body. But metastatic tumors are still considered to be the same cancer type as where the cancer first started. This is why breast cancer that has spread to the bone or lungs is still breast cancer.… Continue reading →