In reply to Shen.

RunStatus.Cancelled tells EG to abandon the run of this particular task and return control back to the main application. However, that doesn't affect any downstream tasks in the process flow.

The only way to affect the downstream tasks would be to use a Conditional node around the task, which allows you put something like if-then logic around a node in a process flow. That's not part of the custom task though -- this has to be applied in the project.