Women who followed a supervised, structured exercise program during treatment after surgery for stage I or stage II breast cancer had better heart health compared to women who weren’t part of the exercise program, according to a Norwegian study.
The research was presented on Dec. 7, 2018, at the San Antonio Breast Cancer Symposium. Read the abstract of “Cardiovascular function and the effect of exercise training during adjuvant breast cancer treatment. Results from The EBBA-II trial.”
Doctors call treatments given after surgery adjuvant treatments.
Many studies have found a link between regular exercise and a lower risk of being diagnosed with breast cancer, as well as a lower risk of breast cancer coming back (recurrence).
As a result, the American Cancer Society and many doctors recommend that women who’ve been diagnosed with breast cancer, as well as those who haven’t, exercise regularly — about 4–5 hours per week at a moderate intensity level. (Brisk walking is considered moderate intensity exercise.) This is about double what the U.S. Department of Health and Human Services recommends per week for adults.
In addition, receiving chemotherapy to treat breast cancer increases a woman’s risk of metabolic syndrome; obesity also increases this risk.
Metabolic syndrome is a cluster of health conditions, including high blood pressure, excess body fat, and high cholesterol. In turn, metabolic syndrome increases the risk of heart disease, type 2 diabetes, and breast cancer recurrence.
Research suggests women with metabolic syndrome are 17% more likely to be diagnosed with breast cancer, three times more likely to have a breast cancer recurrence, and two times more likely to die from breast cancer.
The EBBA-II trial
According to the researchers who did this study, called the EBBA-II trial, while previous studies have shown exercise can benefit people who have been diagnosed with breast cancer, not much research has looked at the type, intensity, and duration of exercise during adjuvant treatment for breast cancer and what type of health benefits exercise during adjuvant treatment offers.
“Breast cancer survival rates have improved, but many survivors experience a decline in cardiovascular function,” said the study’s lead author, Inger Thune, M.D., Ph.D., professor and senior consultant in oncology at the Oslo University Hospital in Norway. “Treatment-induced cardiotoxicity is a major concern, and cardiovascular disease is a competing cause of death among breast cancer survivors.”
The EBBA-II trial included 375 women age 18 to 75 who had had surgery to remove stage I or stage II breast cancer:
- About 57% were receiving adjuvant chemotherapy.
- 78% were being treated with adjuvant radiation.
- 67% were taking adjuvant hormonal therapy.
Some of the women were receiving more than one adjuvant treatment.
Before the women had any breast cancer treatment, including surgery, the researchers measured the women’s maximum oxygen uptake, called VO2max, a common measure of cardiovascular fitness.
The women were randomly assigned to one of two groups:
- to be part of a 12-month exercise program (187 women)
- to receive the standard of care after surgery according to the Norwegian Breast Cancer Group guidelines (188 women)
The exercise program started 2–3 weeks after breast cancer surgery. Each woman received a detailed, tailored training program based on her fitness level before surgery. The participants met in groups of 10–12 women for 60-minute training sessions led by a trained instructor twice a week during the 12 months. The training sessions included a mix of aerobic exercise, weight training, and stretching. The women in the exercise program also were asked to do at least 120 minutes of exercise at home each week, for a total of 240 minutes (4 hours) of exercise per week. The women also kept exercise diaries.
Women in the standard of care group received information on healthy eating and exercise.
The researchers measured the women’s VO2max 6 months after the exercise program started and at the end of the exercise program.
The benefits of exercise during adjuvant treatment
Six months after the exercise program started, both groups of women had a decline in average VO2max levels compared to levels before surgery. Thune said this is typical in the months after surgery or any other breast cancer treatment. Still, the women in the standard of care group had a larger decline — 10% — than women in the exercise group where levels declined only 2.7%.
At the end of the 12 months, women in the exercise group had improved their VO2max by 2.3% compared to their VO2max before surgery. Women in the standard of care group had a 3.8% decrease in VO2max compared to their VO2max levels before surgery.
Because chemotherapy can have a big negative effect on fitness, the researchers also specifically looked at women being treated with adjuvant chemotherapy to see if the exercise program helped offset any declines.
Women being treated with adjuvant chemotherapy in the exercise group had returned to their pre-surgery VO2max level by the end of the 12-month program. Women in the standard of care group had a 6.4% drop in VO2max levels at the end of the 12 months compared to their pre-surgery levels.
Overall, the women had no issues or side effects as a result of being part of the exercise program.
"Patients should discuss their [exercise] plans with their doctor, but in general, our study supports incorporation of supervised clinical exercise programs into breast cancer treatment guidelines," Thune said. “Aside from the cardiovascular benefits measured in this study, exercise may also help reduce fatigue and improve quality of life.”
"This one is the first [study] to show a cardiac performance benefit, but all of these studies show that exercise is beneficial," said Kent Osborne, director of the Dan L Duncan Comprehensive Cancer Center at Baylor College of Medicine and co-director of the San Antonio Breast Cancer Symposium. "The question is, how do you get doctors to do this with their patients.
“Another problem is trying to convince the family not to treat the patient as if the patient is sick," he continued. "Patients should be allowed to do whatever they want to do. I encourage patients to go back to work. I encourage them to exercise. It is very difficult to institute a formal exercise program because of issues of reimbursement for doctors' time and other factors."
Make exercise part of your treatment plan
If you’re still recovering from breast cancer treatment, along with being busy with work, household chores, and family matters, finding time to exercise almost every day can seem impossible.
It can help to break up your exercise into 20- or 30-minute sessions that add up to about 4 hours per week. Walking is a great way to start. Maybe you walk 30 minutes before going to work and 20 minutes on your lunch break. You can add a few more minutes by parking farther away from your building or taking mass transit. Or you can make plans to walk with a friend after work — you’re more likely to stick with an exercise plan if someone else is counting on you. Plus, you can socialize at the same time.
Along with healthy diet and lifestyle choices, regular exercise is one of the best things women can do to feel their best and to keep the risk of breast cancer recurrence as low as it can be. This study adds to other research suggesting that regular exercise can help keep your physical and mental health in top shape. No matter how old you are, it’s never too late or too soon to get moving. And once you do start, keep at it!
In this study, some of the women who participated in the exercise program had never owned a pair of running shoes or exercise clothing before the study started, but they did very well.
Visit the Breastcancer.org Exercise section for tips on exercising safely and how to stick to an exercise routine.
To talk with others about the benefits of exercise, share exercise tips, and get encouragement, join the Breastcancer.org Discussion Board forum Fitness and Getting Back in Shape.
Written by: Jamie DePolo, senior editor
Reviewed by: Brian Wojciechowski, M.D., medical adviser