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BLOG: December 2007
Breast cancer studies
Should you be afraid of breast cancer? Not as much as just a decade ago, but there are certainly reasons for concern and, with it, need to be well informed. The question is: where do you get reliable information?
Breast cancer studies are all over the place with their conclusions of what, when and how much matters in breast cancer prevention and treatment. One has to question both purpose of conducting these en masse studies and their usefulness for treating any individual case - which is what really matters.
Along with some general data on breast cancer, let's take a look at the results of two recent breast cancer studies.
Statistically, breast cancer is becoming less intimidating. Even with the high incidence rate in the U.S., the chances are about 1 in 800 that you'll be told you have it this year, and about 1 in 10 in your lifetime. And, with the current overall 10-year survival rate of 80% (American Cancer Society), your chances to die from it are about 1 in 50, or lower (accounting for the likely further drop in death rate in the foreseeable future).
Of course, these figures are for women; for men, the chances of getting breast cancer are about 100 times lower.
Then, what also matters is your age, ethnicity, breast cancer stage and type. At about 60 years of age, or over, your chances of developing breast cancer within the next 10 years are 1 in 25, quickly falling to 1 in 70 at the age of 40, and to 1 in 2000 at the age of 20 (American Cancer Society). White women run the highest risk, which is, at 1 in 750, nearly twice that of the lowest-risk group, American Indian/Alaska native (National Cancer Institute).
And, depending on how far spread (stage, measured by tumor size and degree of tissue penetration, number of lymph nodes affected, or possible metastasis), and how aggressive (low, intermediate or high) it is, the 5-year survival rate varies from 100% to 20%.
While the odds of getting breast cancer are not very alarming, the fact is that, due to the size of population,
terrifyingly large number of real woman does fall pray to it.
This year alone, some 180,000 women in the U.S. will be diagnosed with breast cancer, and over 40,000 will die from it. And, be sure, having breast cancer, and dying from it is no fun at all. That makes it so terribly important to give all that can help to those that need to fight it off and survive.
Of course, there are drugs, radiation and chemotherapy. If your breast cancer cells have active receptors for both, estrogen and progesterone (ER- and PR-positive, respectively, about half of all breast cancer cases), you may be able to get away with drug-only treatment; Tamoxifen can help in about two out of three patients here.
For the ER-positive alone, its efficacy is only about half as good.
And if your breast cancer is ER- and PR-negative, thus not fueled by the hormones (about 1/4 of patients), you'll likely be recommended harsher treatments, or possibly benefit from Herceptin therapy if your breast cancer cells turn out to be strongly HER2-positive (human epidermal growth factor receptor 2, for a protein whose excess promotes the cancer cell growth).
Oddly enough, while hormone-negative breast cancer seems to be the worse of the two, and is, in fact, more deadly within a 5-year period from the diagnosis, its longer term mortality diminishes. To the contrary, that from hormone-positive breast cancer doesn't; after 15-year period, the two have about the same mortality rate.
In order to be effective, drug treatment needs to extend to long periods of time. In principle, the longer the better, except that it exposes you proportionally more to a potential harm from treatment's adverse side effects, which can be both, unpleasant and very serious.
In short, you are certainly not guaranteed protection from breast cancer by conventional medical treatments except, usually, for the earliest stage. In other words, anything else that can help is very welcome. What first comes to mind are, naturally, diet and lifestyle. There must be something in it, just looking at the fact that women in China have about
six times lower breast cancer incidence than in the U.S.!
Japanese women, with more than four times lower incidence than U.S. women, lose that protective aura within two generations, or less, from coming to live in the U.S. That rules out God-given resistance to breast cancer, and points out to the diet, environment and lifestyle. Wouldn't it be great to have the cancer incidence here cut down by three, four times, or even more, just by adopting healthier habits? What is it that breast cancer studies suggest in this respect?
Let's start with diet. Plant-based diet helps, or doesn't, depending on the study.
High-protein seems to be negative if coming from meat, but could be helpful if it is of dairy origin (so is it the protein, or something else, like vitamin D that dairy products are often enriched with?).
Total fat intake does matter, or doesn't, depending on the study (not a few studies do not control for the type of fat consumed, which makes the result, whatever it happened to be, inconclusive). Type of fat may matter, but only for pre-menopausal women. The exception may be hydrogenated fats, which are likely making it worse, and Omega-3 that probably do help.
There is no conclusive data on the effect of refined sugar and carbohydrates; some studies indicate that high carbohydrate intake could be more harmful that high fat intake, but they often don't separate simple carbohydrates (sugars) from complex - another shot in the dark by design. Dietary fiber seems helpful. Vitamin C and A, and some other selected supplements may and may not be helpful, depends on the study.
Alcohol and obesity are a minus, but weight gain after the diagnosis may and may not matter.
Smoking will likely make it worse, while adequate exercise is recommended, even if it doesn't seem to have a direct effect.
If you feel this doesn't give you much to hold onto, that is not just your personal impression. It seems as if most of these studies didn't really have a good clue what to begin with, or what factors to control, with study designs and results inevitably going in all directions.
Two recent studies on the effect of diet on breast cancer outcome are merely continuation of this trend. One of them, Woman's Healthy Eating and Living Study (WHEL) has found that intervention group of 1537 women with early-stage breast cancer, after 4 years on diet richer in vegetables, fruit and fiber, with fat calories limited to 15-20% of the total, had no appreciably lower rate of "invasive breast cancer event" (nearly 17%), nor mortality (about 10%) than the control group. The came to the same conclusion for 7.3 follow-up years.
However, another recent study, The Women's Intervention Nutrition Study (WINS), has found that reduction in fat intake alone to 25% of total calories, or less, down from ~40% average for the typical diet (the type of fat intake wasn't controlled) significantly improved relapse-free survival rate - 24% lower risk - in a total of 2437 post-menopausal women (975 intervention vs. 1462 control) starting out with early-stage breast cancer, in 5-year follow up period after conventional treatment. But there was a little string attached: practically all the benefit came from the risk reduction in women with ER-negative breast cancer (42% lower than in the control group as a whole).
Now, there is significant difference between the two studies in how they were conducted, with the WHEL being based mainly on self-reported data, and WINS being a direct, controlled clinical study. The problem with indirect studies is that subject information is less reliable, and often biased. How else to explain that WHEL participants claiming even more significant reduction in fat intake, combined with the increased intake of fruit and vegetables,
have actually gained weight,
about as much as the control group? On the other hand, WINS women on less reduced fat intake experienced significant weight loss.
Looking at the basic design of these and other studies, one can't avoid seeing the obvious: they are just flawed from the very start. There is a number of potentially important factors, and unless most of them - preferably all - are controlled,
the results are of very limited use - if any.
If the goal is to establish role of nutrition and nutrients in the development and treatment of breast cancer - or any other disease - wouldn't it be logical to start with monitoring a complete nutritional status of the participants from the beginning to the end of the trial, combined with a type-specific information on dietary intake of fats, proteins, carbohydrates, nutritional supplements and water?
Wouldn't it be also logical to take into account environmental factors, such as degree of exposure and sensitivity to estrogen mimics, like plasticizers, pesticides (which can also affect cell functioning through other mechanisms), detergents, PCBs and alike, which can fuel ER-positive cancer growth. Also, not all fruit, vegetables or other natural foods are equally good for everything. For breast cancer - and some other as well - those like Brassica family (broccoli, Brussels sprouts, cabbage), whose specific phytochemicals
help metabolize estrogen mimics into good estrogen
(2-hydroxylase metabolite), and not its bad, cancerous metabolite, 16-hydroxylase, are certainly more important than, say, peppers or potato, especially if these come laden with hydrogenated fats.
Participants could be tested for how well they metabolize estrogen mimics (Estronex test). Other relevant factors could, and should be controlled as well. These would have to include genetic monitoring, since it all comes down to a malfunction at the genetic level (this is separate from breast cancers caused by inherited genetic glitch, which account for about 10% of the total). So far, altered function of about dozen specific genes, including BRCA 1 and 2, p53, ATM, Check-2, and others, has been linked to breast cancer growth.
Sure, such approach would make a study more complex and expensive, but what is the alternative? Exactly what we have now: breast cancer studies coming up with incomplete, questionable, contradicting pieces of information, that really help no one.
Studies based on (very) partially controlled factors cannot be expected to give meaningful results. While one can reasonably assume that most of the ineffectiveness of breast cancer studies, particularly in the diet and lifestyle area, comes from those conducting them lacking in necessary specific knowledge (read: training) of the complexity of factors affecting human health, the question why it remains ignored and tolerated by those in charge of public health can not be avoided.