eli5: How does radiation both cause and cure cancer? I know it can be targeted, but I still don’t understand how it’s not causing cancer at it’s target? How does chemo work? And how does chemo and radiation work together?

Question

Sorry if the flair is wrong. Biology or chemistry?

In: Biology

Answer 1

Radiation can kill cells just by the sheer amount of damage it causes. But it can also damage DNA in a way that doesn’t cause the cell to die, but repair itself. In some cases, the radiation damages a certain gene that encodes for something important. For example, your cells have genes called tumour-suppressor genes which actively stop cells from becoming cancerous. If they get hit by the radiation and damaged, then the cell begins to develop in a way that leads to cancer.

Chemotherapy is toxic to your body and kills cells that replicate quickly. Cancer cells are like this, but also skin and cells that line your gut. They interfere with normal cell division so faster dividing cells are more impacted than slower dividing cells.

Chemoradiotherapy is combining the two in certain cancers to achieve the effect of the two. Targeted radiotherapy can wipe out a large mass which makes it easier to remove surgically, but there might be remnant cells that aren’t visible to the eye that are far from the mass. The hope is that chemotherapy will kill those cells as well and cure you from cancer.