Correlation of high body mass index with more advanced localized prostate cancer at radical prostatectomy is not reflected in PSA level and PSA density but is seen in PSA mass

Objectives: Prostate cancer screening algorithms and preoperative nomograms do not include patients' body mass index (BMI). We evaluated outcomes at radical prostatectomy (RP) adjusted to BMI. Methods: Serum prostate-specific antigen (PSA) levels, PSA mass, PSA density (PSAD), and RP findings were analyzed with respect to BMI in 4,926 men who underwent RP between 2005 and 2014. Results: In total, 1,001 (20.3%) men were normal weight, 2,547 (51.7%) were overweight, and 1,378 (28%) were obese. Median PSA levels (ng/mL) were normal weight, 5.0; overweight, 5.1; and obese, 5.2 (P = .094). Median PSA mass increased with increasing BMI: 15.9 vs 17.4 vs 19.4 μg (P < .001). Median PSAD was not significantly different: 0.11 vs 0.11 vs 0.11 ng/mL/g (P = .084). Median prostate weight increased with increasing BMI: 44 vs 45 vs 49 g (P < .001). Median prostatectomy tumor volume increased with increasing BMI: 3.9 vs 4.7 vs 5.9 cm3 (P < .001). Overweight and obese patients had a higher Gleason score and more locally advanced cancer (P < .001). Frequency of positive surgical margins increased with higher BMIs (P < .001). Frequency of lymph node metastasis did not differ significantly (P = .088). Conclusions: While BMI correlates with tumor volume, Gleason score, and extent of disease at RP, there is no routinely measured clinical parameter reflecting this. Only PSA mass highlights this correlation. Thus, BMI and potentially PSA mass should be taken into account in predictive algorithms pertaining to prostate cancer and its surgical treatment.