The following article features coverage from the American Society of Clinical Oncology 2019 meeting. Click here to read more of Oncology Nurse Advisor‘s conference coverage.

A low-fat dietary intervention reduced the risk of dying from breast cancer among postmenopausal women without a prior diagnosis of breast cancer, according to the results of the prospective, randomized Women’s Health Initiative clinical trial ( identifier: NCT00000611). The trial results will be reported at the upcoming 2019 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago.1

The trial included 48,835 postmenopausal women aged between 50 and 79 years from 40 clinical centers in the United States. Eligible women had no prior diagnosis of breast cancer, a normal mammogram, and a daily fat consumption of least 32%. At baseline, women on the trial had an average age of 62 years and an average body mass index of 28; the majority of women were white (81%).

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Between 1993 and 1998, women were randomly assigned to either the dietary intervention group (19,541 women) or the control group (29,294 women). Those in the dietary intervention group participated in a low-fat diet with increased servings of fruits, vegetables, and grains, and those in the control group continued their normal diet. The target daily fat consumption was 20% for the dietary intervention group, but most did not achieve this, having a daily fat consumption of 25%.

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Women participated in the dietary intervention for a median of 8.5 years, and at a median of 19.6 years of follow-up, 3374 cases of breast cancer were diagnosed. The low-fat dietary intervention group had a 21% reduced risk of dying from breast cancer compared with the control group (hazard ratio [HR], 0.79; 95% CI, 0.64-0.97; P =.025).

“To our review, this is the only study providing randomized clinical trial evidence that an intervention can reduce a woman’s risk of dying from breast cancer,” wrote the primary study author Rowan Chlebowski, MD, PhD, FASCO, from the Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center in Torrance, California, during a press conference prior to the meeting.2


  1. Chlebowski RT, Aragaki AK, Anderson GL, et al. Low-fat dietary pattern and long-term breast cancer incidence and mortality: The Women’s Health Initiative randomized clinical trial. Poster presented at: 2019 American Society of Clinical Oncology Annual Meeting; Chicago, IL; May 31-June 4, 2019. Abstract 520.
  2. American Society of Clinical Oncology (ASCO). Balanced, low-fat diet reduces risk of death from breast cancer in postmenopausal women. Published May 15, 2019. Accessed May 23, 2019.

This article originally appeared on Cancer Therapy Advisor