Obesity, Serum Prostate Specific Antigen and Prostate Size: Implications for Prostate Cancer Detection
Abstract
Purpose:
Obesity has been associated with lower serum testosterone, theoretically resulting in decreased PSA production. Obesity has also been associated with prostatic enlargement, making the detection of existent cancer more difficult. Together these findings would result in an apparent protective effect of obesity on prostate cancer risk due to technical detection issues unrelated to cancer biology. We examined the association between BMI, and PSA and prostate weight in a cohort of men undergoing RP.
Materials and Methods:
We evaluated the association of BMI with prostate weight and PSA using linear regression, adjusting for patient age at RP, year of RP, race, and pathological stage and grade in 1,414 men treated with RP between 1988 and 2004 at the 5 equal access medical centers that comprise the Shared Equal Access Regional Cancer Hospital Database.
Results:
On multivariate analysis increasing BMI was associated with increasing prostate weight but only in men younger than 63 years and not in men 63 years or older (p-trend <0.001 and 0.44, respectively). In men younger than 63 years mean multivariate adjusted prostate weight ± SE in those with a BMI of less than 25 vs 30 to 34.9 kg/m2 was 33.8 ± 1.4 vs 41.4 ± 1.6 gm. There was no significant association between BMI and preoperative PSA (p-trend = 0.70).
Conclusions:
In a cohort of men undergoing RP obesity was associated with larger prostate size but only in younger men. There was no association between BMI and PSA. Assuming equal PSA, the degree of prostatic enlargement observed in younger obese men in this study would be expected to result in a modest decrease in the odds of detecting prostate cancer in a contemporary series of PSA screened men due to the decreased sensitivity of cancer detection related to larger prostate size. Obesity may appear protective for prostate cancer in younger men due to technical issues unrelated to cancer biology.
References
- 1 : Prevalence and trends in obesity among US adults, 1999-2000. JAMA2002; 288: 1723. Google Scholar
- 2 : The underlying basis for obesity: relationship to cancer. J Nutr2002; 132: 3451S. Google Scholar
- 3 : Body size and prostate cancer: a 20-year follow-up study among 135006 Swedish construction workers. J Natl Cancer Inst1997; 89: 385. Google Scholar
- 4 : Height, body mass index, and prostate cancer: a follow-up of 950000 Norwegian men. Br J Cancer2003; 89: 1237. Google Scholar
- 5 : Anthropometry in relation to prostate cancer risk in the Netherlands Cohort Study. Am J Epidemiol2000; 151: 541. Google Scholar
- 6 : Prostate cancer in relation to diet, physical activity, and body size in blacks, whites, and Asians in the United States and Canada. J Natl Cancer Inst1995; 87: 652. Google Scholar
- 7 : Body mass index and risk of prostate cancer in U.S. health professionals. J Natl Cancer Inst2003; 95: 1240. Google Scholar
- 8 : Body size and serum levels of insulin and leptin in relation to the risk of benign prostatic hyperplasia. J Urol2002; 168: 599. Link, Google Scholar
- 9 : Hyperinsulinaemia as a risk factor for developing benign prostatic hyperplasia. Eur Urol2001; 39: 151. Google Scholar
- 10 : Race as an outcome predictor after radical prostatectomy: results from the Shared Equal Access Regional Cancer Hospital (SEARCH) database. Urology2002; 60: 670. Google Scholar
- 11 : Carcinoma extent in prostate needle biopsy tissue in the prediction of whole gland tumor volume in a screening population. Am J Clin Pathol2002; 118: 442. Google Scholar
- 12 : Insulin-like growth factor I, insulin-like growth factor binding protein 3, and urologic measures of benign prostatic hyperplasia. Am J Epidemiol2003; 157: 784. Google Scholar
- 13 : Influence of age and endocrine factors on the volume of benign prostatic hyperplasia. J Urol1991; 145: 405. Link, Google Scholar
- 14 : High fat diet increases the weight of rat ventral prostate. Prostate2001; 49: 1. Google Scholar
- 15 : The association of body mass index and prostate-specific antigen in a population-based study. Cancer2005; 103: 1092. Google Scholar
- 16 : Demographic and clinical factors as determinants of serum levels of prostate specific antigen and its derivatives. Anticancer Res2004; 24: 2069. Google Scholar
- 17 : Influence of age, anthropometry, and hepatic and renal function on serum prostate-specific antigen levels in healthy middle-age men. Urology2003; 61: 132. Google Scholar
- 18 : Predictors for biopsy outcome in the European Randomized Study of Screening for Prostate Cancer (Rotterdam region). Prostate1999; 39: 316. Google Scholar
- 19 : Predicting the outcome of prostate biopsy in screen-positive men by a multilayer perceptron network. Urology2000; 56: 418. Google Scholar
- 20 : Body mass index as a predictor of prostate cancer: development versus detection on biopsy. Urology2005; 66: 108. Google Scholar
- 21 : Prognostic significance of tumor volume after radical prostatectomy: a multivariate analysis of pathological prognostic factors. Eur Urol2003; 43: 7739. Google Scholar
