I can’t find an official AP ruling on this, but I see no reason not to capitalize Breast Cancer Awareness Month. It’s an official observation and would seem to fall in line with AP’s capitalization rules.
Don’t capitalize related words such as breast cancer (in other uses), pink, pink ribbon, etc., unless it's part of an official name (e.g., GateHouse's Pink sites).
AP recently weighed in on another October event. From Ask the Editor:
Q. All Hallows Eve? All Hallow's Eve? All Hallows' Eve?
A. Allhallows Eve, or AP Stylebook's preferred Halloween.
All Saints’ Day and All Souls’ Day are three words each, however.