As usual its very complex and opinions vary.
I suggest you read the links above and do some additional searches. In general terms it seems there are simply insufficient trials on prevention through diet. In consequence you are unlikely to find the definative answers you are looking for. It is a case of finding out as much as possible and making a value judgement. Try it and monitor the results would appear the optimal solution in you can have access to the tests.
Do remember that it appears that plants are of complex chemical construction and work in multiple different ways that are only begining to be understood.
Here are some more links that may help.
The first is about using flaxseed together with oestradoil testing. This seems a good idea. If your adviser is dubious or you are worried, "try it and monitor" would seem a good compromise. I dont know what the tests costs, or what would be considered most appropriate fat blood mamary pap etc. "Life extension" a supplement site has a huge range of blood tests, and members get a discount and access to professional advice. ( I have no association)
http://store.yahoo.com/annieapplesee...altusflax.html
This link is an examination of items with oestrogenic effects, which is mind boggling, and in a sense adds to the confusion, and at the other extreme engenders a "what the heck" outlook unless you live in a bubble (non plastic) or virgin rainforest.
http://store.yahoo.com/annieapplesee...altusflax.html
This is the overall concusion from one of the links above.
OVERALL CONCLUSION (ABSTRACT)
"Flaxseed inhibited the growth of ER+ MCF 7 human breast cancer in nude mice in the presence of high or low levels of estrogen. The effect of flaxseed at high estrogen level was dose dependent. Flaxseed enhanced rather than antagonized the inhibitory effect of TAM on the growth of ER+ human breast cancer in nude mice. TAM and flaxseed components reduced the tumor growth by decreasing the tumor cell proliferation and increasing apoptosis. Other mechanisms likely include those that have been mentioned earlier. The results are encouraging and provide some scientific justification for the clinical testing of flaxseed in both pre- and post- menopausal breast cancer patients taking TAM. If similar results are observed in patients, then flaxseed may be consumed with TAM to help reduce TAM resistance i.e. tumor growth after prolonged intake of tamoxifen."
And this from the other
......"In conclusion, FS inhibits the growth of human estrogen receptor positive breast cancer, and strengthens the inhibitory effect of TAM on the tumor growth. FS complements rather than antagonizes the effect of TAM on human tumor growth."........
As to digestion there are varied views of whether seed or oil is better. There is the possibility that the body uses the plants protective chemicals too. Cover your option maybe - sensible amounts of both. Whatever you do on the balance of probabilities the high omega three content will very likley improve your general health.
As usual it is best if you check things out for yourself. Please take the time to read the above links - if you dont understand bits dont worry you are not the only one - me too - but it will come to make a little sense and it is helpful in forming a view, or being able to sensibly take up your point with your oncologist / advisors.
RB