Firstly I am not an oncologist and have had no education in this area.  I would be talking to the doc about the physiology of lactation.  If I understand correctly, tamoxifen works by either suppressing oestrogen production or reception.  Lactating women have very low oestrogen levels while exclusively breastfeeding.  Weaning to take tamoxifen sounds a bit like digging a hole so that you can fill it in. There won't be any research that mum can rely on so in the end she and her doc will have to weigh risks but if s/he is the kind of person who will read, inform and partner a patient in making her decision, they might be able to come to a solution they're both happy with.
Nina Berry
Australia

             ***********************************************

Archives: http://community.lsoft.com/archives/LACTNET.html
To reach list owners: [log in to unmask]
Mail all list management commands to: [log in to unmask]
COMMANDS:
1. To temporarily stop your subscription write in the body of an email: set lactnet nomail
2. To start it again: set lactnet mail
3. To unsubscribe: unsubscribe lactnet
4. To get a comprehensive list of rules and directions: get lactnet welcome