Research increasingly shows that “energy balance” is important in breast cancer. Learn why exercise, weight, and diet are important for breast cancer patients.

1. Healthy Living After A Breast Cancer
Diagnosis
Jennifer Ligibel, MD
Dana-Farber Cancer Institute
Young Women’s Forum
October 13, 2017

2. Research increasingly shows that “energy balance”
is important in breast cancer
Energy we take in Energy we “spend” What remains
(Food) (Exercise + Metabolism) (Weight)
_ =
Each of these factors has been linked to breast cancer

3. But diet and exercise recommendations for
preventing and treating cancer are everywhere–
and they don’t always agree!

4. How can you sort out fact from fiction?
Is there an optimal diet to prevent
breast cancer recurrence?
Is exercise important for breast cancer
survivors?

5. Most studies looking at links between diet
and cancer are “Observational” studies
• In this kind of study, a large group of people is asked what kind
of food they are eating
• Participants are followed over time (“Observed”) to see who gets
cancer or has a recurrence, and links are made between cancer
and the kinds of diet people consumed
Pro
Studies many different
diet factors and cancers
at once
Con
Hard to separate out other
factors (people who eat
certain types of diets may be
different in other ways, like
exercise more or weigh less)

6. What kinds of foods have been linked to
cancer risk?
• Red meat has been linked to colon
cancer risk
– Try to consume < 18 ounces/week
• Smoked and processed meats have
been linked to stomach and other
cancers
– Even small amounts linked to slight increase
in cancer risk
• Alcohol has been linked to risk of
head and neck, liver, esophageal and
breast cancers
– Women should consume no more than 1 drink
day; men no more than 2

7. Do we have any evidence that
changing diet could prevent
breast cancer?

8. One study looked at whether eating a
Mediterranean diet affected the risk of
developing breast cancer
Mediterranean diet:
• Lots of veggies, fish,
olive oil
• Not much red meat or
processed food
• A little wine

9. Study basics
• Primary goal: study the effect of a Mediterranean diet on heart
disease
• Study also looked at effect of the diet on risk of breast cancer in
women taking part in the study
• Study participants divided into 3 groups
• Mediterranean diet + extra virgin olive oil
• Mediterranean diet + nuts
• Usual diet
• About 4000 women who had never had breast cancer took part

10. Did the diets make a difference?
• Not very many women developed breast
cancer—only 35 during the course of the
study
• Women in the olive oil group had a 62% lower
risk of breast cancer compared to usual diet
group
• Women in the nut group had a 38% lower risk
of breast cancer compared to usual diet group

11. Is there any evidence that a
specific diet or food has health
benefits for women who have
already had breast cancer?

12. “Observing” trials show links between some
types of food and breast cancer recurrence
• Diets high in fat linked to
higher cancer recurrence
• Weak links between
higher intake of fiber and
protein and lower cancer
recurrence
• No real link with
carbohydrate intake

13. Most studies looking at the direct
effect of a particular food on
cancer were done using cells in
test tubes or in animals, not people

14. Broccoli and Breast Cancer

15. What’s the Evidence?
• Different kinds of breast cancer cells
were grown in a lab
• Breast cancer cells were exposed to
different concentrations of nutrients
isolated from broccoli
• At high concentrations, the growth rate
of breast cancer cells slowed and cells
had a higher death rate

16. Broccoli in rats
• Young female rats divided into groups; some given 5 days of
nutrients isolated from broccoli, some given typical food and no
broccoli
• All rats exposed to chemical that
causes breast cancer
• Rats given high doses of broccoli
nutrients about 50% less likely to
develop breast cancer

17. What about in people?
• No studies testing what happens in women with breast
cancer who increase broccoli in their diet
• Several studies asked women without breast cancer
how much broccoli (and other fruits and vegetables
they ate)
• Results not very consistent
• Some studies showed a slightly lower rate of breast
cancer in women who ate more broccoli
• Other studies showed no difference

18. But is there any evidence that diet
after breast cancer is linked to risk
of cancer recurrence?

19. Two studies looked at whether changing diet
after diagnosis would lower risk of recurrence
Women’s Interventional Nutrition Study (WINS)
• Goal: test the effect of
reducing dietary fat after
breast cancer diagnosis on
recurrence
• Study enrolled ~2400 women
with Stage I-III breast cancer
• WINS Diet : reduce fat to
15% of total calories
.

20. Second trial testing effect of changing diet on
breast cancer recurrence
• Goal: to test the effect of eating
less fat, and more fruits,
vegetables and fiber on the risk
of breast cancer recurrence
• Included 3088 women with
stage I-III breast cancer
Women’s Healthy Eating and Living (WHEL) Trial

21. Both trials successfully changed
participants’ diets
WINS Trial
• Low fat diet group cut fat by
33%
• Usual diet group cut fat by
9%
WHEL Trial
• Diet group
– Cut fat by 25%
– Increased fruits and vegetables
by 5 servings per day
• Usual diet group
– Decreased fat by 4%
– No change in fruits and
vegetable servings

22. Results of trials were a bit different
WINS Trial
• Low fat diet group had a
reduced risk of breast cancer
recurrence
• Benefit mostly in patients with
estrogen negative cancers
• Benefits seemed to be
reduced over time
WHEL Trial
• No difference in recurrence
risk in diet and usual care
groups
• No benefits of diet program
seen in any patient group

23. No clear evidence that a
specific diet can reduce or
increase the risk of breast
cancer recurrence, based on
what we know now

24. What about exercise?
• Women who exercise less
likely to get breast cancer
• A few studies have looked at
links between exercise after
breast cancer diagnosis and
risk of recurrence
• Exercise linked to 30-50%
lower risk of cancer
recurrence!

25. What kind of exercise were these women
doing?
• The most common exercise was walking at a
moderate pace
• Benefits seen with walking at a 3-mile-per-hour
pace for half an hour per day
• Not necessary to run a marathon! (of course you
always can if you like)

26. Exercise also shown to have other
benefits in breast cancer survivors
• Better quality of life
• More energy
• Less arthritis and joint pain
• Better self esteem and mood
• Plus:
decreased risk of diabetes and heart disease!

27. How could exercise effect breast cancer?
• Enrolled breast cancer survivors
who were not exercising
• Assigned them to exercise or
usual care group
• Exercise program:
– Strength training
– Cardio at home
• Study showed that exercise
lowered levels of insulin, a
hormone linked to breast cancer
The Dana-Farber Exercise and Insulin Study

28. The Breast Cancer Weight Loss Trial

29. BWEL Study Basics
• The BWEL study will test the ability of a weight loss program to
reduce rates of breast cancer recurrence
• BWEL is a randomized trial: half of the study participants will
take part in the weight loss program and half will receive a
breast cancer education program
• The study will enroll 3136 women in the US and Canada
• Study is designed to test whether weight loss reduces the risk of
cancer recurrence by 20%

30. Who can take part in BWEL?
• Women with breast cancer diagnosed within the past year
• Must have a BMI of at least 27kg/m2
• Must have HER-2 negative breast cancer
• Cancer must be stage II or III
• Patients can’t have metastatic breast cancer
• Patients can’t be taking certain types of diabetes medicines
• Must be completed with surgery and with chemotherapy (if it
was used)

31. BWEL Weight Loss Program
• Goal: to help participants lose
10% of their body weight
through diet and exercise
• Participants are paired with a
health coach
• Receive 42 phone calls over
2 years
• Record weight, food intake
and exercise

32. Conclusions
• Exercise, weight and diet are
important in breast cancer
patients
• It’s never too late to make healthy
changes in lifestyle!
• More research is needed to
understand how changes in diet
and exercise could affect breast
cancer recurrence rates