Currently, the way that the cancel sends functionality for Quick Sends inside of Distributed Marketing is that you have the place the related list view for the sends on the quick send page. In this related list view, you are able to see ALL scheduled sends that are related to that specific Quick Send Message.
When working inside of a federated business model where your users are franchisees that only have visibility in records that they own this functionality does not work. We currently have deployed the Quick Send Lighting Component on both the Lead and Contact page layout to allow for users to directly communicate with the leads/contacts on a one-to-one basis. But when we tried to roll out the functionality around scheduled sends we came to the realization that the quick sends are related to email in a primary fashion and not the lead/contact so you can pleas that related list view on the record page layout.
To sum it up, in order for the functionality to work as you would expect based on how other features have been rolled out we need to have the ability to place the related list view of the scheduled sends (so that they can be canceled) on the record page layout.