Impact of Low-Fat Diet on Breast Cancer Survival Rates
Study Overview
A recent study published in JAMA Oncology investigated whether a low-fat breast cancer diet after diagnosis can enhance overall survival rates. Breast cancer ranks as the second most prevalent cancer among women, affecting approximately one in eight during their lifetime. Increased awareness surrounding breast cancer has resulted from educational initiatives on symptoms and treatment options, as well as efforts to identify associated risk factors.
Dietary Factors Influencing Breast Cancer
Research indicates that diet may play a significant role in breast cancer risk, alongside age, sex, and genetic factors. Numerous studies have explored how dietary habits affect breast cancer risk, with some suggesting that high-fat diets may elevate the risk in postmenopausal women. Prevention guidelines advocate for increased consumption of fruits, vegetables, and grains, while some studies also link obesity to higher recurrence rates of breast cancer.
Previous Study Uncertainties
Researchers have sought to determine whether a specific diet can impact cancer recurrence and survival rates post-diagnosis. Scientists from Hope National Medical Center in Duarte, California, conducted a secondary analysis of the Women’s Health Initiative (WHI), a randomized clinical trial that initially suggested a connection between a low-fat diet and improved survival for breast cancer patients. The WHI included 48,835 postmenopausal women, who reported a fat intake exceeding 32% at the study’s outset. Participants were randomly assigned to either a dietary intervention group—focused on reduced fat intake and increased fruits, vegetables, and grains—or a control group maintaining their usual diet. However, the initial results did not clarify whether improved survival was due to pre-existing dietary patterns or the intervention itself.
Clarifying Dietary Impact on Breast Cancer Outcomes
The secondary analysis published in JAMA Oncology included a randomized controlled trial involving 19,541 postmenopausal women diagnosed with breast cancer. Participants in the intervention group reduced their fat intake by 20% while significantly increasing their consumption of fruits, vegetables, and grains. The control group of 29,294 women continued with their regular diets. The median dietary intervention lasted 8.5 years, with a median follow-up period of 11.5 years post-diagnosis.
Survival Rates Among Women on a Low-Fat Diet
During the dietary intervention, 1,764 cases of breast cancer were diagnosed, with 671 in the intervention group and 1,093 in the control group. The overall survival rate was 82% for women adhering to the low-fat diet, compared to 78% for those in the control group. The intervention group reported 68 deaths from breast cancer, while the control group recorded 120. Additionally, there were significantly fewer deaths from other cancers and cardiovascular diseases in the group following the dietary intervention.
Long-Term Benefits of Dietary Interventions
Results indicated that the positive effects of the diet on overall survival rates increased over time from the point of diagnosis. This suggests that prolonged adherence to a low-fat diet may significantly influence survival outcomes for breast cancer patients. The study’s randomized design, large sample size, comprehensive follow-up, and extended observation period are notable strengths. However, the researchers acknowledged limitations, including the need for confirmatory trials and insufficient information on patients’ breast cancer therapies.
Conclusion: The Role of Diet in Breast Cancer Outcomes
The findings suggest that women following a low-fat diet rich in fruits, vegetables, and grains experienced higher overall survival rates from breast cancer compared to those with their usual diets. Researchers propose that this enhanced survival may be linked to improved outcomes across multiple causes of death.
Written by Preeti Paul, MS Biochemistry
Reference: Rowan T. Chlebowski et al. Association of Low-Fat Dietary Pattern With Breast Cancer Overall Survival. A secondary analysis of the Women’s Health Initiative randomized clinical trial. JAMA Oncol. doi:10.1001/jamaoncol.2018.1212