Oncologist perspectives on pharmacologic intervention versus lifestyle intervention in breast cancer
The hardest of all diet intervention studies have to be dietary intervention studies to reduce cancer. The just published study in the Journal of the National Cancer Institute is a watershed. (Chlebowski, R. et al. Dietary Fat Reduction and Breast Cancer Outcome: Interim Efficacy Results From the Women's Intervention Nutrition Study J Natl Cancer Inst, Dec 2006; 98: 1767 - 1776).

When I scanned the initial news headlines, it's so interesting how people view it. One headline read "Low fat diets fail to reduce breast cancer deaths." Another read "Low fat diets reduce breast cancer deaths." Others were in between. But here's the take home message, cutting through all the background noise. Women with estrogen receptor negative breast cancer cut their recurrence rate by 60% if they stayed with a diet in which fewer than 20% of calories were from fat.

Nothing but nothing has ever achieved results like that before. Not chemotherapy. Not radiotherapy. If results like this were obtained with a new drug, it would be the breast cancer treatment breakthrough of the decade. But it will get buried. Why? Firstly, people like their food. And people don't like being told how to eat. Secondly, there is no money to be made by anybody. No money for surgeons, radiotherapists, medical oncologists. And it costs the patient nothing. Probably low fat diets are cheaper than high fat diets.

People can debate this all they want. We can wait another 20 years for the next dietary intervention trial to mature.

But if you are diagnosed with breast cancer and it turns out to be estrogen receptor negative you can either wait 20 years for the proof beyond reasonable doubt which will never come, or you can go with the preponderance of evidence, which is that you can cut your chance of having cancer come back 60% if you cut the fat in your diet by 30%.  Has to be one of the biggest no brainers of our time.

I'm on an email list for an excellent non-profit organization called breastcancer.org.

They featured a Q&A conference, where experts fielded questions. Here is a relevant exchange:


Question: I have hormone-negative breast cancer. The latest research suggests a low-fat diet lowers recurrence rates as much as 66% for hormone-negative cancers. I try to exercise at least one to two hours most days of the week. But I remain about 20 lbs. overweight. I take vitamins. I now feel like every time I eat a fat gram, I'm killing myself. Does cancer "feed" on fat, so less fat means I'm "starving" the cancer cell?

Answer (Dr. Griggs, U of Michigan Assoc Prof of Medicine/Medical Oncology): It's an unfortunate side effect of this type of research that we shift the burden sometimes to the woman who has had or does have breast cancer. Although one wants to feel strong and powerful and in control, in many ways we're limited by the disease itself or the available treatments. Your question brings up two points. The first is that how delightful it is to know that for women with  hormone-receptor-negative cancers there is something that can be done in addition to chemotherapy. Certainly, the results of this study which were presented at another meeting and appear to be consistent, offer encouragement for just that reason. The second point is that an individual woman's prognosis and risk of recurrence is sometimes a mystery to us. My concern with this kind of research is that it shifts the blame to the person, should she have a recurrence.

My comments:

The italicized part of the above quote is the understatement of the year. "...something that can be done in addition to chemotherapy." As if adjuvant chemotherapy of receptor negative breast cancer is so highly effective that's it's merely nice to have a little add-on of a dietary intervention.

It's momentous. A two thirds reduction in recurrence rates! No toxic drugs. No expense. Granted it's a bit of a sacrifice to lower one's dietary fat to less than 20% of total calories in the context of a good diet emphasizing vegetables, fruits, low fat dairy, controlled portions of healthy-type meats, etc. But compare and contrast the "sacrifice" to do this with the sacrifices require to endure adjuvant chemotherapy which produces "chemo-brain" and other assorted serious toxicities, to say nothing of the expense.

The researchers themselves are being very cautious. They are currently embarking on a larger study, to include more lifestyle interventions (e.g. exercise), which will take years and years to organize, complete, and publish. Were they talking about some type of intervention which was toxic and expensive, I could defend the understated response from the oncologic community. But here we are talking about something which is completely non-toxic and inexpensive and which had a hugely beneficial effect.

What constitutes more eqregious malpractice? Failure to make a responsible effort to administer adjuvant chemotherapy in estrogen receptor negative breast cancer or failure to make a responsible effort to have one's patients follow a prudent and reasonable and inexpensive dietary plan for which best evidence now indicates that the dietary intervention reduces recurrence rates by 60% and produces no toxicity and has a minimal cost.

I'm personally much less concerned about some patients feeling "blame," than I am concerned about patients suffering toxicity from chemotherapy administered in the absence of a reasonable effort at achieving dietary changes and having recurrences notwithstanding the ineffective chemotherapy, having eschewed the opportunity to utilize a simple and non-toxic dietary intervention which reduced recurrences by 60%.

- Larry Weisenthal