Influence of obesity on tumour volume in patients with prostate cancer


  • Take Home Message: Body mass index is independently associated with prostate cancer volume at radical prostatectomy.

Umberto Capitanio, University Vita-Salute San Raffaele, Via Olgettina 60, 20132, Milan, Italy. e-mail:


Study Type – Prognosis (individual cohort)

Level of Evidence 2b

What's known on the subject? and What does the study add?

Obesity is associated with more aggressive prostate cancer.

Prostate cancer tumour volume is affected by excess weight, after adjustment for all possible clinical and pathological confounders.


  • • To investigate the association between body mass index and tumour volume at radical prostatectomy in a large European population.


  • • Recent data support the hypothesis that the hormonal environment in overweight and obese men may alter androgen-dependent prostate growth. Body mass index (BMI) has been implicated in prostate cancer pathophysiology.
  • • We analysed 1275 patients with prostate cancer who underwent radical prostatectomy at a single tertiary care institution. Mean tumour volume (TV) was evaluated according to BMI WHO categories (normal <25 kg/m2 vs overweight 25–30 kg/m2 vs obese 30–35 kg/m2 vs severely obese >35 kg/m2).
  • • Univariable linear regression analyses targeted the association between BMI and TV at radical prostatectomy. Multivariable analyses were adjusted for age, prostate-specific antigen value, biopsy Gleason sum, clinical stage and prostate volume.


  • • Mean BMI was 26.3 kg/m2 (median 26; range 16.7–42.0). Mean TV was 5.6 mL (median 3.3; range 0.1–61.2). The mean prostate-specific antigen value was 10.3 ng/dL (median 6.6; range 0.3–327).
  • • The mean TV was 5.0, 5.8, 6.3 and 9.2 mL in normal, overweight, obese and severely obese patients, respectively (P= 0.03). TVs in men with a normal BMI were 84% smaller than in severely obese men (5.0 vs 9.2 mL).
  • • On univariable analysis, BMI was correlated with TV at radical prostatectomy (P < 0.001). On multivariable analysis, BMI reached the independent predictor status after adjustment for age, prostate-specific antigen value, biopsy Gleason score, clinical stage and prostate volume (P= 0.03).


  • • We showed that BMI is independently associated with prostate cancer volume at radical prostatectomy. The present results confirm that obesity may play a key role in prostate cancer pathophysiology.