This is an article I came upon with my research.  I am making no claims.  For those of you that don't know the FDA has tightened down restrictions on supplement claims made that have anything to do with Cancer.  There are approved claims for things such as Cholesterol and others, but not yet Cancer. That means that credible data is hard to find and must be garnered from a variety of sources.  You'll notice this article the authors were writing for the "Journal of Veterinary Dermatology."  Sad that data has to be hidden from people that could possibly benefit.

The researchers felt strongly enough about this information that they tried to get it into the literature through very unconventional means.  Either way, more work needs to be done to substantiate these claims.  The nice thing is, many people are already taking Omega-3's for a variety of other reasons, so possibly another benefit to this very useful supplement.

"Medical Uses of Essential Fatty Acids (EFAs)" (abstract)

This is an extensive review article on the role of essential fatty acids. In 1956 Sinclair suggested that abnormalities of essential fatty acid metabolism may be underlying factors in many of the degenerative diseases of western society, including cardiovascular disease, cancer and inflammatory disorders. Recent evidence suggests the role of essential fatty acids in cancer, vascular disease, diabetic complications and inflammatory disorders such as arthritis and atopic eczema.

In research dating to the 1930's, it was noted that 1 or 2 gm per day of linoleic acid was adequate to control the skin lesions of essential fatty acid deficiency whereas 30 to 60 gm per day of linoleic acid were required to have beneficial effects in atopic eczema. Essential fatty acids were, for almost 20 years, the mainstay of treatment, then fell into disuse with the introduction of topical steroids. There does not appear to be a dietary deficiency in atopic eczema. However, all the metabolites of linoleic acid including gamma-linolenic acid (GLA) dihomogamma-linolenic acid (DGLA) and arachidonic acid (AA) are all reduced.

This suggests a block in the conversion of linoleic acid to gamma-linolenic acid. Evening primrose oil (a source of gamma-linolenic acid) at a few grams per day has shown significant improvement in skin disorders and itch compared to placebo. Toxicity from other medications can be reduced. Diabetes has an effect on blocking delta 6 desaturase and delta 5 desaturase enzymes. In eczema, GLA and DGLA tend to be reduced more than arachidonic acid. They all may be lowered in diabetes. Very large doses of linoleic acid have been shown to reduce by two thirds the risk of heart and eye disease over a period of about 6 years. The administration of gamma-linolenic acid from evening primrose oil (EPO) has been shown to reverse and treat diabetic neuropathies in animal models. Double-blind, placebo-controlled trials in humans with diabetic nerve damage have shown that EPO can stop or reverse nerve damage in human diabetics. Animal models have shown that trans fatty acids inhibit the conversion of linoleic acid to its metabolites.

There is now strong evidence from a large amount of research that trans fatty acids are likely to evoke cardiovascular disease. In treatment, it is important to give both omega-6 and omega-3 fatty acids. Large amounts of omega-3 fatty acids, when given alone, have the effect of depleting omega-6 fatty acids. This researcher says that the first cardiovascular study which provides omega-6 and omega-3 fatty acids beyond the rate limiting 6-desaturation step has shown a 3-fold reduction in reocclusion after human femoral arteries are open by balloon angioplasty.

In a wide range of animal models GLA and DGLA of the n-6 series, and EPA of the n-3 series, are antiinflammatory due to stimulation of antiinflammatory prostaglandins. Both omega-3 and omega-6 fatty acids are probably needed for best results. There is evidence that cancer cells are depleted of essential fatty acids. Oxygenated metabolites of essential fatty acids are produced either by cyclooxygenase or lipoxygenase enzymes and involved in normal control of cell division. Providing essential fatty acids to cancer cells beyond the 6-desaturation step, which appears to be slow in many cancer cells, might control cancer cell division.

In vitro and animal evidence has now shown this consistently. Supplementation with GLA, DGLA and EPA are able to kill all human cancer cell lines tested to date at concentrations which do not harm normal cells.

For success in utilizing essential fatty acids in cancer, doses must be high and the cancer cells must be exposed to essential fatty acids for an extended period of time. IV administration of the salts of GLA has been developed. The lithium salt has been found to be beneficial due to its reduced toxicity and ability to be easily monitored. In over 30 patients with inoperable pancreatic cancer, and in smaller numbers with terminal breast and colon cancer, there have been some dramatic dose-dependent survival-extending responses. Pancreatic cancer is generally inoperable and no other treatment is given other than radiation. In various studies, the mean duration of survival after the diagnosis has been 80 to 120 days. With regards to GLA supplementation, the mean survival at the highest dose is now 300 days. This constitutes an approximate 3-fold extension of life without side effects."

Medical Uses of Essential Fatty Acids (EFAs)", Horrobin, David F., Veterinary Dermatology, 1993;4(4):161-166

Editor's Note:
I don't think that IV administering of Omega-3 Fatty Acids and the Omega-6 GLA is necessary for prevention, if this data is accurate.  Supplementing with sufficient quantities of both might be a first step in your Cancer Prevention Regimen.  Personally, I take 3g/day of EPA/DHA (Fish Oil) and 2g/day of Omega-6 Fatty Acid, GLA (Gamma Linoleic Acid).   

One thing is for certain, more research needs to be done in this area.  The research needs to definitely be done by an objective third-party and not someone that benefits dollar-wise from how Cancer is currently being treated.  One would think that the American Cancer Society would be spearheading this sort of prevention effort.  I guess all the "Races for the Cure" would stop if a cure was actually found!  How about some accountability for all the dollars going into research.

To me it appears the American Cancer Society isn't "Racing for the Cure" it is more strolling, meandering, or possibly "Moseying for the Cure."  To say nothing about prevention, which they've done very little considering the millions of dollars they raise each year from well-meaning individuals.  How long before those well-meaning individuals demand the reseachers get off their collective asses and find a cure?!

Research isn't about throwing huge amounts of money into a hole, it's about solving problems.  The American Cancer Society needs to be gutted and rebuilt.  They should take a lesson from the American Heart Association which has recommended Omega-3's (a supplement) as part of a prevention program.  Solutions exist, now find them, and do it quick!