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I thought that the news release sounded like it was describing Lillian Thompson's work, although in terms she would never use. Here's the original source:
"1: Clinical Cancer Research 2005 May 15;11(10):3828-35.
Dietary flaxseed alters tumor biological markers in postmenopausal breast
cancer.
Thompson LU, Chen JM, Li T, Strasser-Weippl K, Goss PE.
Department of Nutritional Sciences, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, Canada.
PURPOSE: Flaxseed, the richest source of mammalian lignan precursors, has previously been shown to reduce the growth of tumors in rats. This study examined, in a randomized double-blind placebo-controlled clinical trial, the effects of dietary flaxseed on tumor biological markers and urinary lignan excretion in postmenopausal patients with newly diagnosed breast cancer.
EXPERIMENTAL DESIGN: Patients were randomized to daily intake of either a 25 g flaxseed-containing muffin (n = 19) or a control (placebo) muffin (n = 13). At the time of diagnosis and again at definitive surgery, tumor tissue was analyzed for the rate of tumor cell proliferation (Ki-67 labeling index, primary end point), apoptosis, c-erbB2 expression, and estrogen and progesterone receptor levels. Twenty-four-hour urine samples were analyzed for lignans, and 3-day diet records were evaluated for macronutrient and caloric intake. Mean treatment times were 39 and 32 days in the placebo and flaxseed groups, respectively.
RESULTS: Reductions in Ki-67 labeling index (34.2%; P = 0.001) and in c-erbB2 expression (71.0%; P = 0.003) and an increase in apoptosis (30.7%; P = 0.007) were observed in the flaxseed, but not in the placebo group. No significant differences in caloric and macronutrient intake were seen between groups and between pre- and posttreatment periods. A significant increase in mean urinary lignan excretion was observed in the flaxseed group (1,300%; P < 0.01) compared with placebo controls. The total intake of flaxseed was correlated with changes in c-erbB2 score (r = -0.373; P = 0.036) and apoptotic index (r = 0.495; P < 0.004). CONCLUSION: Dietary flaxseed has the potential to reduce tumor growth in
patients with breast cancer.
PMID: 15897583 [PubMed - in process]"
Possible explanations for warnings against flaxseed:
1) Hi Ki-67 actually seems to help anthracyclines work, so lowering it would not be a good idea. I wouldn't mix flaxseed and anthracyclines or any other drugs that depended on high Ki-67.
2) Although most mouse studies have found flaxseed to be beneficial in slowing breast cancer, there is a mouse study of a mouse with Her2+ breast cancer in which flaxseed worsened the time to progression and overall survival.
3) The effect in premenopausal women might be different (although I would think just for ER+ tumors). The Her2 pathway is a completely separate pathway from the ER/PR one I think (somebody correct me if I'm wrong here).
4) The study period was just one month. The longer effects are unknown, which could be particularly relevant for ER+ (think of the concerns about tamoxifen's effect possibly reversing and Her2).
5) There are contraindications. As I recall, flaxseed should not be taken with medicine since it lessens absorption.
The numbers involved are small (just 32), but reaching statistical significance given the small numbers is impressive. It would be great if they could test whether flaxseed improved survival or lessened recurrence in women who have completed treatment.
There might not be anything special about the muffins. I suspect that it was just a way of keeping people from knowing whether they were in the control or flaxseed group.
Personally I wondered though why this research wasn't carried out, as is usually the case, on women with secondaries, such as those who were on a break from chemo. Delaying treatment for primary cancer by a few weeks raises too many ethical questions, since the treatment just slowed the cancer, it didn't cause it to shrink.
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