Week-to-week gains: The Borgias.
Week-to-week losses: Nurse Jackie.
Below are the Showtime TV show ratings averages as of Sunday, April 28, 2013; the end of week 31 of the 2012-13 season. Ratings are typically the best way to tell if a show will be cancelled or renewed but pay channels take other factors into consideration.
There are fewer Showtime shows and they don’t adhere to the traditional season. So, for comparison, I’ve also included the most recent seasons of shows that aren’t currently airing.