If they look a lot like it then they are called well differentiated. If they do not look much at all like it, then poorly differentiated. Moderately differentiated cancers are of intermediate grade. In general, well differentiated cancers are expected to behave the best, poorly differentiated the worst. Following diagnosis the next step is staging.
Stage refers to the extent of the cancer.
Each cancer, by organ, has its own staging system. The official staging system for accredited cancer registries is the TNM system. T, indicates the size of the primary tumor. It is usually subdivided into four substages. N, indicates the status of the regional lymphnodes.