SU-E-T-576: Obesity as a Factor in Prostate Cancer Treatment Modality and Outcomes

Authors


Abstract

Purpose:

Prostate cancer is the most frequently diagnosed malignancy in American males. To date, no single study has examined the effect of obesity on the outcomes of all three treatment modalities in a single population. We examined the relationship between obesity and prostate cancer treatment decisions as well as outcomes.

Methods:

We conducted a retrospective observational cohort study of the patients treated for prostate cancer with curative intent between January 1998 and December 2010. Wilcoxon ranksum and Chi-Square tests were used to analyze the association between treatment mode and body mass index (BMI). Cox proportional Hazards models adjusted for risk category, age, and androgen deprivation therapy (ADT) were performed to evaluate the effects of BMI on overall, disease-free, biochemical recurrence-free, incontinence-free, and impotence-free survival.

Results:

A total of 1681 patients were included in the analysis, including 338 that received BT, 439 that received EBRT, and 904 that received RP. When BMI was assessed as a continuous variable, median BMI was higher in patients treated with BT (29.4) than in those treated with EBRT (28.8) or RP (28.9) (P = 0.0677, Wilcoxon rank-sum test). After stratifying BMI into two groups (BMI < 29.4 or ≥ 29.4), Chi-Square test showed that the treatment mode was significantly related to BMI where the proportion of high BMI individuals undergoing was 50.9% for BT, 42.4% for EBRT, and 43.2% for RP (P = 0.0309). Cox proportional hazards modeling was used to assess the relationship between BMI and survival outcomes. For patients receiving EBRT, BMI was a significant risk factor for incontinence-free survival where HR for incontinence in the lower BMI group was 0.515 (95% CI 0.307–0.865, P = 0.0121).

Conclusion:

BMI appears to be related to prostate cancer treatment decisions, High BMI (≥ 29.4) is associated with poorer incontinence-free survival for EBRT.

This study was supported by a grant from the Marshfield Clinic Research Foundation

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