SAN ANTONIO — A year-long structured exercise program initiated 3 weeks after surgery for breast cancer significantly attenuated expected declines in cardiovascular (CV) function as patients continued through treatment, a Norwegian randomized, placebo-controlled study found.

The program, which took place outdoors and incorporated aerobics, weight bearing movement, and stretching, enabled almost full recovery of CV function at 12 months.

The study was presented here during the San Antonio Breast Cancer Symposium (SABCS) 2018.

“It is striking that for all [patient] groups — whether they received chemotherapy or not — there was a really good effect of being in the physical activity program,” said lead author Inger Thune, MD, PhD, Oslo University Hospital, Norway.

“Our study supports incorporation of supervised clinical exercise programs into breast cancer treatment guidelines,” Thune told Medscape Medical News at a meeting press briefing.

“CV function during treatment is a reflection of a patient’s physical function later on in life, because [poor CV function] is a marker of susceptibility to comorbidity and to overall survivorship, so its loss can be a very important issue in daily life,” she added.

Kent Osborne, MD, of the Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas, wholeheartedly agreed with the idea of patients exercising throughout treatment as much as possible.

“You’d be surprised how little activity patients get after their diagnosis, and this is partly related to their families telling them, ‘You need to rest because you are on this chemotherapy,’ ” he told reporters.

“But patients need to be as active as they can. They will tolerate chemotherapy better and have better outcomes, so we have to convince the family not to treat the patient as if they are sick,” emphasized Osborne, who moderated the press event.

Study Details

The Energy Balance and Breast Cancer Aspect (EBBA-II) trial enrolled 545 women with stage I or II breast cancer following surgical excision of their tumor.

The mean age of patients was 55 years, and the mean body mass index was approximately 25 kg/m². More than 70% of both groups had invasive breast cancer.

Approximately 22% of both groups also had lymph node metastases, and about 70% of women in both groups underwent breast-conserving surgery.

Slightly more than half of both groups underwent chemotherapy. About half of these patients received an anthracycline-based regimen, and some 40% received a taxane.

Of both groups, 80% also underwent radiotherapy, and almost 60% were treated with some form of endocrine therapy.

Three weeks after undergoing breast cancer surgery, patients were randomly assigned either to participate in a 12-month exercise program or to receive standard care.

Patients performed aerobic exercises of moderate to high intensity; there was also a weight-bearing and stretching component to the program.

The exercise program was tailored to an individual’s maximal oxygen uptake (VO₂max), as assessed prior to their undergoing surgery. VO₂max is a common measure of CV fitness.

Patients exercised together twice a week for 60 minutes per session and were instructed to exercise at home for another 120 minutes a week to achieve a total of 240 minutes a week of activity.

“CV capacity was assessed before surgery, at 6 months, and again at 12 months,” Thune noted.

“And at a mean of 31 mL/kg/min, the VO₂max in both groups was basically identical at baseline,” she said.

Focus on Chemo Recipients

At 6 months, “the intervention group did much better at preserving their CV function than the control group, among whom there was an 8.9% decrease in VO₂max,” Thune reported.

By way of comparison, VO₂max in the intervention group dropped by only 2.7% at 6 months, the investigators noted.

At 12 months, CV function among those who participated in the exercise program had rebounded to almost the same VO₂max levels as prior to surgery. On the other hand, those who received standard care had a 3.8% decrease in VO₂max at 12 months relative to presurgical baseline levels (P < .001).

When investigators assessed VO₂ levels among 242 patients who had not undergone chemotherapy, findings were again significantly in favor of the intervention group.

After 6 months of exercise, “patients in the intervention group had a 1.6% increase in the level of their VO₂max, which was maintained at 12 months of follow-up,” Thune noted.

In contrast, patients in the control group had a 2.7% decrease in VO₂max at 6 months. This loss persisted to 12 months, she added.

The researchers also analyzed changes in CV function for patients who had received any kind of chemotherapy as well as those who had been treated with a taxane.

Among 295 patients who received some form of chemotherapy, exercise participants experienced a 9% decrease in VO₂max at 6 months, compared with a 14.2% decrease among control patients who received standard care.

Again by 12 months, VO₂max had almost rebounded to presurgical baseline levels among those who exercised, whereas for control patients, VO₂max was 6.4% lower than at baseline (P < .001).

A separate analysis was conducted for 212 patients who had received a taxane as part of their chemotherapy regimen.

For these patients, treatment effects were most pronounced. There was a 17.5% drop in VO₂max at 6 months among control patients and a significant, though slightly less pronounced, drop among exercise participants.

However, at 12 months, VO₂max had rebounded to only about 1.4% below presurgical baseline levels among exercise participants. For the control group, there was a 7.3% decrement in VO₂max (P < .05).

“It is striking that for all these groups — whether they received chemotherapy or not — there was a really good effect of being in the physical activity program,” Thune noted.

“We believe that breast cancer patients receiving chemotherapy should be offered a tailored exercise program based on pretreatment levels of physical function,” she concluded.