Cancer dormancy is a widespread phenomenon.
Actually nearly all cancers are incurable chronic diseases with periods of dormancy.
Disease free survival (DSF) is a dormancy measure which is observed in any cancer. 
I discuss an important  study on melanoma dormancy published by NJ Crawley and HF Seigler.
It describes disease free survival (DFS) off five groups of melanoma patients. 
In 20% patients melanoma dormancy lasted more than 5 years

Cancer is generally viewed as a parasite  encroaching on a passive host. It evolves in a Darwinian fashion, outwitting its environment, the host. Yet cancer is more than just the tumor. It is the interaction between the organism and its tumor. Actually the host imposes a homeostasis on the tumor which may last for years.