Diet and Exercise for Breast Cancer Patients

February 2009

Over the last year, there has been a shift in what we know about diet and breast cancer. Data from the Women's Healthy Eating and Living (WHEL) trial has been analyzed and published and it isn’t what we expected.  This study followed 3,088 women who had been diagnosed with breast cancer. Of the total women, 1,537 were encouraged to change their diet to eat more vegetables, fruits and fiber and to decrease the fat they ate. The goal was to eat 5 vegetable servings, 3 fruit servings and 16 ounces of vegetable juice each day while at the same time cutting down fat.  The control group was encouraged to simply aim for the ‘Five a day’ total of fruits and vegetable that the government recommends.


When this study was started in the mid 1990s, these recommendations were considered to be the ‘healthy diet’ for breast cancer survival and so this is what we’ve encouraged our patients to do. 

The researchers tracked cancer recurrence, diagnosis of a new primary cancer, or death from any cause in both groups.   The extra fruits and vegetables made no difference.

Here is the bottom line:

“Over the mean 7.3-year follow-up, 256 women in the intervention group (16.7%) vs 262 in the comparison group (16.9%) experienced an invasive breast cancer event, and 155 intervention group women (10.1%) vs 160 comparison group women (10.3%) died.”

All those years of careful eating didn’t appear to make an appreciable difference. 

While WHEL pretty much trashed the idea of making basic diet changes for breast cancer patients, a number of studies now tell us that exercise is very valuable for this same group of people.  This data started appearing several years ago:

Back in August 2006, the Journal of Clinical Oncology (JCO) reported that exercise could cut risk of dying for patients with advanced colon cancer by almost half. [1] Another JCO paper in the same issue, reported that women with colorectal cancer who exercised, decreased their hazard ratio of dying from cancer by 61% and from all causes by 57%.[2] A December 2007 article in the International Journal of Cancer analyzed the risk of colon cancer in 79,295 women. Women who exercised, lowered their risk of getting colon cancer by 23%.  Those who exercised more than 4 hours a week had a 40% lower risk. [3]

Not being fat may be the key here more than being in good physical condition, at least when it comes to breast cancer. At the 2008 annual meeting of the American Society of Clinical Oncology (ASCO), several studies focused on Body Mass Index (BMI) and hip to waist ratios.

Breast cancer patients survive longer without disease, improve response to cancer treatment, reduce complications and live longer overall if they just lose weight.

Obese women have worse outcomes. Chemotherapy does a better job of shrinking tumors in normal weight patients than in heavy ones. Obese patients have more hormone negative tumors (a bad thing) and more late stage tumors (also bad).[4] Big women with higher BMIs, have larger breast tumors, more positive lymph nodes, and worse tumor stage and grade.[5]

Irwin’s 2008 ASCO paper that looked at exercise and breast cancer is probably the most striking.  Analyzing data from the Health, Eating, Activity and Lifestyle Study, the researchers found an association between pre and post-diagnosis physical activity and mortality.   Compared with women who increased physical activity after diagnosis had a 45% lower risk of death.  Women who decreased physical activity after diagnosis had a four-fold greater risk of death. [6]

Thus in the last year we have the WHEL trial that says that basic diet changes have no effect on breast cancer and the HEAL study that says exercise has a tremendous effect. 

There are interesting tidbits of information being teased out of the WHEL trial data that are still valuable.  According to Dr.  Lise Alschuler,

“…the WHEL study was grabbed up by the press and the “Diet makes no difference in preventing breast cancer” headline made fast tracks around the country. However, this was premature.  This was a multi-million dollar study that deserves much more analysis. There are likely sub-groups that did benefit and in this study we finally have some data to look at.  For instance, I was talking with one of the WHEL researchers who shared with me that there appeared to be a trend for prevention associated with increased consumption of cruciferous vegetables.  What we need now is to re-focus on the WHEL study and discover its hidden gems.” [private communication Feb. 2, 2009]

Since the initial WHEL data was first published in 2007, several papers have come out providing secondary and more detailed analysis.  For example, in April 2008, Mortimer told us that of the women taking tamoxifen, those with hot flashes did better in the long run. “Hot flashes were a stronger predictor of breast cancer specific outcome than age, hormone receptor status, or even the difference in the stage of the cancer at diagnosis (Stage I versus Stage II). These findings suggest an association between side effects, efficacy, and tamoxifen metabolism.” [7]

With breast cancer, exercise is proving to be far more important than the quantity of fruits and vegetables consumed. The effect of diet and exercise on body shape, weight and on both estrogen levels and estrogen metabolism are far more important.[8]  Of course this doesn’t give one license to eat whatever.  A diet that causes weight gain is clearly counterproductive. A diet that helps weight loss is still desirable.  The fatter women in the WHEL study who lost weight following the suggested diet did gain protection. 

Simple Guidelines:

  1. Exercise regularly: minimum of four hours per week
  2. Lose weight if over weight
  3. Improve estrogen metabolism and estrogen breakdown.  Measure those estrogen fractions. 
  4. Select foods for specific phytochemical content and specific action.  For example, eat cruciferous vegetables for their sulforaphane content, pomegranate for the ellagic acid, mushrooms because they act as aromatase inhibitors and so on.


  1. Impact of physical activity on cancer recurrence and survival in patients with stage III colon cancer: findings from CALGB 89803. J Clin Oncol. 2006 Aug 1;24(22):3535-41.
  2. Physical activity and survival after colorectal cancer diagnosis. J Clin Oncol. 2006 Aug 1;24(22):3527-34.
  3. Leisure-time physical activity patterns and risk of colon cancer in women. Int J Cancer. 2007 Dec 15;121(12):2776-81.
  4. Litton et al. Relationship Between Obesity and Pathologic Response to Neoadjuvant Chemotherapy Among Women With Operable Breast Cancer. J Clin Oncol 26:4072-4077J
  5. Jensen A. R. et al. The relation between Body Mass Index, comorbidity, choice of surgery, and prognostic factors in early breast cancer - Data from a nation-wide Danish cohort
  6. Irwin ML et al. Influence of Pre- and Postdiagnosis Physical Activity on Mortality in Breast Cancer Survivors: The Health, Eating, Activity, and Lifestyle Study ML J Clin Oncol 26:3958-3964
  7. Mortimer JE et al. Tamoxifen, hot flashes and recurrence in breast cancer. Cancer Res Treat. 2008 Apr;108(3):421-6. Epub 2007 May 31.
  8. Neilson HK et al. Physical activity and postmenopausal breast cancer: proposed biologic mechanisms and areas for future research. Cancer Epidemiol Biomarkers Prev. 2009 Jan;18(1):11-27.
  9. Jensen A. R.  al. The relation between Body Mass Index, comorbidity, choice of surgery, and prognostic factors in early breast cancer - Data from a nation-wide Danish cohort ASCO 2008