Systems, methods, and software for operating a content delivery system to purge cached content are provided herein. In one example, purge messages are transferred for delivery to content delivery nodes (CDNs) in the content delivery system. The CDNs receive the messages, purge content associated with the messages, and compile purge summaries based on the messages. The CDNs further periodically transfer the purge summaries to one another to compare the messages received, and gather purge information for purge messages that may have been inadvertently missed by the CDNs.