Influence of body mass index on prostate-specific antigen failure after androgen suppression and radiation therapy for localized prostate cancer

Authors

  • Jason A. Efstathiou MD, PhD,

    Corresponding author
    1. Department of Radiation Oncology, Brigham and Women's Hospital and Dana Farber Cancer Institute, Boston, Massachusetts
    • Department of Radiation Oncology, Brigham & Women's Hospital and Dana Farber Cancer Institute, 75 Francis St., L2, Boston, MA 02115
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    • Fax: (617) 632-2742.

  • Ming-Hui Chen PhD,

    1. Department of Statistics, University of Connecticut, Storrs, Connecticut
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  • Andrew A. Renshaw MD,

    1. Department of Pathology, Brigham and Women's Hospital and Dana Farber Cancer Institute, Boston, Massachusetts
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  • Marian J. Loffredo RN, OCN,

    1. Department of Radiation Oncology, Brigham and Women's Hospital and Dana Farber Cancer Institute, Boston, Massachusetts
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  • Anthony V. D'Amico MD, PhD

    1. Department of Radiation Oncology, Brigham and Women's Hospital and Dana Farber Cancer Institute, Boston, Massachusetts
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Abstract

BACKGROUND

Increasing body mass index (BMI) is associated with shorter time to prostate-specific antigen (PSA) failure after radical prostatectomy. Whether BMI is associated with time to PSA failure was investigated in men treated with androgen suppression therapy (AST) and radiation therapy (RT) for clinically localized prostate cancer.

METHODS

The observational prospective cohort study consisted of 102 men with clinically localized prostate cancer who received 70 Gy RT with 6 months of AST on a single arm of a randomized trial between December 1995 and April 2001. Height and weight data were available at baseline for 99 (97%) of the men, from which BMI was calculated. Adjusting for age (continuous) and known prognostic factors including PSA level (continuous), Gleason score, and T-category, Cox regression analyses were performed to analyze whether BMI (continuous) was associated with time to PSA failure (PSA >1.0 ng/mL and increasing >0.2 ng/mL on 2 consecutive visits).

RESULTS

Median age and median BMI (interquartile range [IQR]) at baseline was 72 (69.1–74.7) years and 27.4 (24.8–30.7) kg/m,2 respectively. In addition to an increasing PSA level (P = .006) and Gleason 8–10 cancer (P = .024), after a median follow-up (IQR) of 6.9 (5.6–8.5) years, an increasing BMI was also significantly associated with a shorter time to PSA failure (adjusted hazard ratio [HR]: 1.10; 95% confidence interval [CI]: 1.01–1.19; P = .026) after RT and AST.

CONCLUSIONS

After adjusting for known prognostic factors, baseline BMI is significantly associated with time to PSA failure after RT and AST for men with clinically localized prostate cancer. Further study is warranted to assess the impact of an increasing BMI after AST administration on PSA failure, prostate cancer-specific, and all-cause mortality. Cancer 2007. © 2007 American Cancer Society.

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