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
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
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
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
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.
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
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
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