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BCRF-Supported Trial Shows Lifestyle Interventions May Improve Breast Cancer Outcomes

By BCRF | March 5, 2024

Study highlights the impact of adopting a healthy diet and exercise regimen early after diagnosis

In the last decade, breast cancer death rates have decreased by one percent each year, in part due to advances in breast cancer treatments, including chemotherapy. While lifesaving, chemotherapy can come with adverse side effects, such as fatigue, nausea, and vomiting, and as a result, patients do not always complete the full course of treatment. Finding ways to make chemotherapy more tolerable for patients who need it and identifying the right patients to receive it are key areas of research in the field.

In a recent study published in the Journal of Clinical Oncology, BCRF investigator Dr. Melinda Irwin reported the results of the LEANer clinical trial showing that lifestyle interventions can potentially improve a patient’s outcomes and quality of life after chemotherapy.

What were the goals of the study?

The LEANer study (Lifestyle, Exercise, and Nutrition Study Early After Diagnosis) was designed to determine how adoption of a healthy diet and exercise intervention early after diagnosis impacts chemotherapy completion. The study also evaluated if the intervention improves pathological complete response (pCR, defined as no residual invasive disease noted in the patient’s pathology report) in women after they completed pre-surgical chemotherapy (neoadjuvant therapy).

How prior LEAN study informed methods of intervention in LEANer

The research team studied 173 women with stage 1-3 breast cancer who were randomly assigned to an intervention group or a standard-of-care group. The intervention group was provided counseling sessions on nutrition and exercise, based on the protocol established in the LEAN study, which was also funded in part by BCRF. In that study, the intervention group participated in counseling sessions that promoted weight loss through both physical activity and achieving or maintaining a healthy diet.

Counseling sessions were conducted over the course of one year and led by registered dietitians (RDs) who were certified specialists in oncology nutrition with additional training in exercise science. They promoted a predominantly plant-based diet, with less than or equal to 18 ounces of red meat per week, and the following daily guidelines:

  • a combination of at least five fruits and/or vegetable servings
  • 25 grams or more of fiber
  • less than 30 grams of added sugar
  • no more than one alcoholic beverage  
  • limited processed foods

A physical activity program was also incorporated into the 30-minute counseling sessions where RDs coached participants on a home-based exercise regimen. The participants were encouraged to engage in 150 minutes or more per week of moderate to vigorous physical activity or 75 minutes per week of vigorous physical activity plus twice-weekly resistance training.

How did the intervention impact study participants?

Participants in the intervention group increased their intake of fruit, vegetables, and fiber during chemotherapy and reported spending more time exercising and strength training than women in the standard-of-care group. Interestingly, the researchers observed that both groups completed chemotherapy doses at very high rates, as measured by the ratio of chemotherapy delivered to the chemotherapy dose prescribed (relative dose intensity, or RDI). The RDI was 93 percent for both groups; an RDI below 85 percent is a common clinical threshold associated with worse chemotherapy effectiveness. This was a surprising finding given that more than 25 percent of patients in observational studies experience a low RDI and are not able to complete prescribed chemotherapy regimens.

However, researchers found that the diet and exercise intervention evaluated in this study was associated with a greater pathological complete response (pCR) in patients with hormone receptor (HR)–positive/HER2-negative and triple-negative breast cancer undergoing presurgical chemotherapy.

Although the mechanisms driving higher pCR rates in the intervention group (53 percent compared to 28 percent in the standard-of-care group) require further investigation, it’s possible that by improving their diets and exercising more, patients experienced reduced inflammation and enhanced immune response.

“That almost twice as many women randomized to the exercise and nutrition intervention during neoadjuvant chemotherapy had no evidence of breast cancer at the time of surgery compared to women randomized to usual care during neoadjuvant chemotherapy was a clinically important finding—yet could be a chance finding as our study was not designed to answer this question as a primary aim,” Dr. Irwin said. “With BCRF funding, we are now initiating a trial in women with triple-negative breast cancer receiving neoadjuvant chemotherapy to specifically answer this question: Does exercising and adopting a high-quality diet during chemotherapy improve pathologic complete response?”

What this means for patients

Adverse side effects of chemotherapy are often so serious that patients or their doctors will discontinue chemotherapy treatments altogether, but reducing chemotherapy doses can have serious consequences. With this study, Dr. Irwin and her research team sought to find lifestyle changes that could give patients better tools for managing side effects, improve their quality of life during treatment, and encourage chemotherapy adherence. The nutrition and exercise interventions in this study specifically address many of the common side effects associated with chemotherapy.

The research team will further investigate how this intervention improves adherence to endocrine therapy and prevents common treatment side effects such as peripheral neuropathy, arthralgia (i.e., joint pain), and cognitive function.  Previous studies have examined how to treat those symptoms after they have occurred, but the LEANer study is one of the first trials to examine if diet and exercise can prevent these common chemotherapy side effects.

The study team is also planning additional investigation into the potential mechanisms behind the increased pCR rates in the intervention group. This finding is particularly exciting as it highlights the role nonpharmaceutical interventions can play in a breast cancer treatment plan and, indeed, these interventions warrant further study.


Anderson, C., Harrigan, M., George, S. M., Ferrucci, L. M., Sanft, T., Irwin, M. L., & Cartmel, B. (2016). Changes in diet quality in a randomized weight loss trial in breast cancer survivors: the lifestyle, exercise, and nutrition (LEAN) study. Npj Breast Cancer, 2(1).

Sanft, T., Harrigan, M., McGowan, C., Cartmel, B., Zupa, M., Li, F., Ferrucci, L. M., Puklin, L., Cao, A., Nguyen, T. H., Neuhouser, M. L., Hershman, D. L., Basen-Engquist, K., Jones, B. A., Knobf, T., Chagpar, A. B., Silber, A., Tanasijevic, A., Ligibel, J. A., & Irwin, M. L. (2023). Randomized Trial of Exercise and Nutrition on chemotherapy completion and pathologic complete response in women with breast Cancer: The Lifestyle, Exercise, and Nutrition Early After Diagnosis Study. Journal of Clinical Oncology, 41(34), 5285–5295.

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