Interesting article on this cancer prevention blog from the World Cancer Research fund: http://blog.wcrf-uk.org/2011/09/exercise-and-cancer/
For those who are living with and beyond breast cancer, check out the Breast Cancer Care new programme - Moving Forward:
http://www.breastcancercare.org.uk/breast-cancer-services/talks-courses-local-support/talks-courses/moving-forward-courses