The description for each Campaign is not included in the Campaign Analysis Report, even when the option is checked off on the Launch page of that report:
If you require the description to be included, you can export the report as a PDF file or choose Display Results on Screen as your Report Format. Either format will include the Campaign Descriptions.
The description is intentionally left out of the Excel and CSV exports because it is not linked with the Campaign in those file types due to where it is located in the results. It would get in the way of adding calculations or re-sorting the data.