Body mass index was associated with upstaging and upgrading in patients with low-risk prostate cancer who met the inclusion criteria for active surveillance.

BACKGROUND

Obesity is associated with an increased risk of high-grade prostate cancer (PCa). The effect of body mass index (BMI) as a predictor of progression in men with low-risk PCa has been only poorly assessed. In this study, we evaluated the association of BMI with progression in patients with low-risk PCa who met the inclusion criteria for the active surveillance (AS) protocol.

METHODS

We assessed 311 patients who underwent radical prostatectomy and were eligible for AS according to the following criteria: clinical stage T2a or less, prostate-specific antigen level < 10 ng/ml, 2 or fewer cores involved with cancer, Gleason score ≤ 6 grade, and prostate-specific antigen density < 0.2 ng/ml/cc. Reclassification was defined as upstaged (pathological stage > pT2) and upgraded (Gleason score ≥ 7; primary Gleason pattern 4) disease. Seminal vesicle invasion, positive lymph nodes, and tumor volume ≥ 0.5 ml were also recorded.

RESULTS

We found that high BMI was significantly associated with upgrading, upstaging, and seminal vesicle invasion, whereas it was not associated with positive lymph nodes or large tumor volume. At multivariate analysis, 1 unit increase of BMI significantly increased the risk of upgrading, upstaging, seminal vesicle invasion, and any outcome by 21%, 23%, 27%, and 20%, respectively. The differences between areas under the receiver operating characteristics curves comparing models with and without BMI were statistically significant for upgrading (P = 0.0002), upstaging (P = 0.0007), and any outcome (P = 0.0001).

CONCLUSIONS

BMI should be a selection criterion for inclusion of patients with low-risk PCa in AS programs. Our results support the idea that obesity is associated with worse prognosis and suggest that a close AS program is an appropriate treatment option for obese subjects.