The worse part about cancers is that there are hundreds of different types and many subtypes. All of them will need unique ways to destroy them, and destroy them for ever, so they don't come back after few short years. This probably will take a long time, hundred or couple of hundreds of years to figure it all out.
To make matter more complicated, in recent research, the stem cells themselves are implicated in harbouring cancerous cells. They might be behind malignus forms of cancerous. They can stay dormant for years, and one day start the same cancer again.
PS. Thanks for article, any news like this is a happy news.