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Dietary fat reduction and breast cancer outcome: interim efficacy results from the Women's Intervention Nutrition Study.

Abstract

BACKGROUND

Preclinical and observational studies suggest a relationship between dietary fat intake and breast cancer, but the association remains controversial. We carried out a randomized, prospective, multicenter clinical trial to test the effect of a dietary intervention designed to reduce fat intake in women with resected, early-stage breast cancer receiving conventional cancer management.

METHODS

A total of 2437 women were randomly assigned between February 1994 and January 2001 in a ratio of 40:60 to dietary intervention (n = 975) or control (n = 1462) groups. An interim analysis was performed after a median follow-up of 60 months when funding for the intervention ceased. Mean differences between dietary intervention and control groups in nutrient intakes and anthropometric variables were compared with t tests. Relapse-free survival was examined using Kaplan-Meier analysis, stratified log-rank tests, and Cox proportional hazards models. Statistical tests were two-sided.

RESULTS

Dietary fat intake was lower in the intervention than in the control group (fat grams/day at 12 months, 33.3 [95% confidence interval {CI} = 32.2 to 34.5] versus 51.3 [95% CI = 50.0 to 52.7], respectively; P<.001), corresponding to a statistically significant (P = .005), 6-pound lower mean body weight in the intervention group. A total of 277 relapse events (local, regional, distant, or ipsilateral breast cancer recurrence or new contralateral breast cancer) have been reported in 96 of 975 (9.8%) women in the dietary group and 181 of 1462 (12.4%) women in the control group. The hazard ratio of relapse events in the intervention group compared with the control group was 0.76 (95% CI = 0.60 to 0.98, P = .077 for stratified log rank and P = .034 for adjusted Cox model analysis). Exploratory analyses suggested a differential effect of the dietary intervention based on hormonal receptor status.

CONCLUSIONS

A lifestyle intervention reducing dietary fat intake, with modest influence on body weight, may improve relapse-free survival of breast cancer patients receiving conventional cancer management. Longer, ongoing nonintervention follow-up will address original protocol design plans, which called for 3 years of follow-up after completion of recruitment.

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  • Authors+Show Affiliations

    ,

    Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, 1124 West Carson St., Building J-3, Torrance, CA 90502-2064, USA. rchlebow@whi.org

    , , , , , , , , , , , , , , , , , , , , ,

    Source

    Journal of the National Cancer Institute 98:24 2006 Dec 20 pg 1767-76

    MeSH

    Adult
    Aged
    Body Weight
    Breast Neoplasms
    Carcinoma, Ductal, Breast
    Carcinoma, Lobular
    Dietary Fats
    Disease-Free Survival
    Female
    Humans
    Kaplan-Meier Estimate
    Lymphatic Metastasis
    Middle Aged
    Neoplasm Staging
    Proportional Hazards Models
    Treatment Outcome

    Pub Type(s)

    Clinical Trial, Phase III
    Journal Article
    Multicenter Study
    Randomized Controlled Trial
    Research Support, N.I.H., Extramural
    Research Support, Non-U.S. Gov't

    Language

    eng

    PubMed ID

    17179478

    Citation

    Chlebowski, Rowan T., et al. "Dietary Fat Reduction and Breast Cancer Outcome: Interim Efficacy Results From the Women's Intervention Nutrition Study." Journal of the National Cancer Institute, vol. 98, no. 24, 2006, pp. 1767-76.
    Chlebowski RT, Blackburn GL, Thomson CA, et al. Dietary fat reduction and breast cancer outcome: interim efficacy results from the Women's Intervention Nutrition Study. J Natl Cancer Inst. 2006;98(24):1767-76.
    Chlebowski, R. T., Blackburn, G. L., Thomson, C. A., Nixon, D. W., Shapiro, A., Hoy, M. K., ... Elashoff, R. M. (2006). Dietary fat reduction and breast cancer outcome: interim efficacy results from the Women's Intervention Nutrition Study. Journal of the National Cancer Institute, 98(24), pp. 1767-76.
    Chlebowski RT, et al. Dietary Fat Reduction and Breast Cancer Outcome: Interim Efficacy Results From the Women's Intervention Nutrition Study. J Natl Cancer Inst. 2006 Dec 20;98(24):1767-76. PubMed PMID: 17179478.
    * Article titles in AMA citation format should be in sentence-case
    TY - JOUR T1 - Dietary fat reduction and breast cancer outcome: interim efficacy results from the Women's Intervention Nutrition Study. AU - Chlebowski,Rowan T, AU - Blackburn,George L, AU - Thomson,Cynthia A, AU - Nixon,Daniel W, AU - Shapiro,Alice, AU - Hoy,M Katherine, AU - Goodman,Marc T, AU - Giuliano,Armando E, AU - Karanja,Njeri, AU - McAndrew,Philomena, AU - Hudis,Clifford, AU - Butler,John, AU - Merkel,Douglas, AU - Kristal,Alan, AU - Caan,Bette, AU - Michaelson,Richard, AU - Vinciguerra,Vincent, AU - Del Prete,Salvatore, AU - Winkler,Marion, AU - Hall,Rayna, AU - Simon,Michael, AU - Winters,Barbara L, AU - Elashoff,Robert M, PY - 2006/12/21/pubmed PY - 2007/1/11/medline PY - 2006/12/21/entrez SP - 1767 EP - 76 JF - Journal of the National Cancer Institute JO - J. Natl. Cancer Inst. VL - 98 IS - 24 N2 - BACKGROUND: Preclinical and observational studies suggest a relationship between dietary fat intake and breast cancer, but the association remains controversial. We carried out a randomized, prospective, multicenter clinical trial to test the effect of a dietary intervention designed to reduce fat intake in women with resected, early-stage breast cancer receiving conventional cancer management. METHODS: A total of 2437 women were randomly assigned between February 1994 and January 2001 in a ratio of 40:60 to dietary intervention (n = 975) or control (n = 1462) groups. An interim analysis was performed after a median follow-up of 60 months when funding for the intervention ceased. Mean differences between dietary intervention and control groups in nutrient intakes and anthropometric variables were compared with t tests. Relapse-free survival was examined using Kaplan-Meier analysis, stratified log-rank tests, and Cox proportional hazards models. Statistical tests were two-sided. RESULTS: Dietary fat intake was lower in the intervention than in the control group (fat grams/day at 12 months, 33.3 [95% confidence interval {CI} = 32.2 to 34.5] versus 51.3 [95% CI = 50.0 to 52.7], respectively; P<.001), corresponding to a statistically significant (P = .005), 6-pound lower mean body weight in the intervention group. A total of 277 relapse events (local, regional, distant, or ipsilateral breast cancer recurrence or new contralateral breast cancer) have been reported in 96 of 975 (9.8%) women in the dietary group and 181 of 1462 (12.4%) women in the control group. The hazard ratio of relapse events in the intervention group compared with the control group was 0.76 (95% CI = 0.60 to 0.98, P = .077 for stratified log rank and P = .034 for adjusted Cox model analysis). Exploratory analyses suggested a differential effect of the dietary intervention based on hormonal receptor status. CONCLUSIONS: A lifestyle intervention reducing dietary fat intake, with modest influence on body weight, may improve relapse-free survival of breast cancer patients receiving conventional cancer management. Longer, ongoing nonintervention follow-up will address original protocol design plans, which called for 3 years of follow-up after completion of recruitment. SN - 1460-2105 UR - https://www.unboundmedicine.com/medline/citation/17179478/full_citation L2 - https://academic.oup.com/jnci/article-lookup/doi/10.1093/jnci/djj494 DB - PRIME DP - Unbound Medicine ER -