Search challenge 10

For this month's search challenge, a question from a primary care physician: A woman's maternal grandmother had breast cancer at the age of 36. As a result, her ob/gyn is recommending screening to begin at 31. What is the evidence for determining when to begin screening patients who have second degree relatives with breast cancer? Is imaging other than mammogram (e.g. MRI) preferred? Does the presence/absence of BRCA 1/2 mutations affect these recommendations?

Post your suggestions in the comments! I'll pull our thoughts together for a follow-up post on the first Monday of August.