Why Does Colon Cancer Reoccur?

Video Transcript

"The reoccurrence goes back to the staging. So the people who recur are the ones that didn't have evidence of metastatic disease at the time when they're diagnosed, so those are the people with stage one, two, three disease and then at some point later it comes back. And when it comes back means that it's visible somewhere else in the body. The likelihood of it recurring inside the colon, the actual cancer that you initially are diagnosed is actually extremely small. There is a risk of developing later colon cancers or other polyps which is why people who already have colon cancer should have more frequent screening, colonoscopies throughout their life. But the higher risk is it developing in another organ. And the reason that it reoccurs is thought to be that there were small cells or small pockets of cells that were already there at the time of diagnosis but they weren't visible on any CAT scan or PET scan or MRI and over time they grew. And that's the basis of why we give chemotherapy for certain patients after they have surgery for colon cancer because theoretically that chemotherapy hopefully will kill those cells, those pockets of cells that are set up shop either in the liver or in the lung and make it so that there's never a recurrence. Unfortunately chemotherapy doesn't a hundred percent guarantee that there won't be a recurrence but particularly for stage three patients there's large bodies of evidence that suggest it does reduce that risk."