When I did some calculations based on one of Dr Menendez's articles on the effects of polyunsaturates on two her2 positive breast cancer cell lines, canola came out better than all of the common oils except for olive oil (tops because of the omega 9) and flax seed oil. Omega 9 seems to get left out in all of these discussions, but Menendez's work indicates that it is key to the point where he was hoping to do a clinical trial on olive oil, which doesn't have a good omega3
mega 6 ratio, but is extremely high in omega 9. The one source of human evidence is that her2 women in Italy who receive taxanes and anthracyclines actually do better than her2 negative ones in the same circumstances.
You're right, though, that the control is problematic because the amounts of omega 9 and 3 (which lowers) versus omega 6 (raises) will have an effect, but canola is probably the least problematic of the common oils. I guess they couldn't have just given them a muffin without the oil in it. The lead researcher on the study, Dr Paul Goss, is also the fellow who wrote the lapatinib article below, so a credible researcher.
My bigger problem with the trial is the short duration. These women only had it for a month and they were all hormone-receptor positive. At least one of Lillian Thompson's articles suggests that ground flaxseed might work a bit like tamoxifen, which suggests that this strategy might not be good over the long term for the same women.
I think it would be good if the same trial was redone in metastatic women, but perhaps with an olive oil group as well.