Obesity and prostate cancer-specific mortality after radical prostatectomy: results from the Shared Equal Access Regional Cancer Hospital (SEARCH) database.

BACKGROUND: At the population level, obesity is associated with prostate cancer (PC) mortality. However, few studies analyzed the associations between obesity and long-term PC-specific outcomes after initial treatment. METHODS: We conducted a retrospective analysis of 4268 radical prostatectomy patients within the Shared Equal Access Regional Cancer Hospital (SEARCH) database. Cox models accounting for known risk factors were used to examine the associations between body mass index (BMI) and PC-specific mortality (PCSM; primary outcome). Secondary outcomes included biochemical recurrence (BCR) and castration-resistant PC (CRPC). BMI was used as a continuous and categorical variable (normal <25 kg/m2, overweight 25-29.9 kg/m2 and obese ⩾30 kg/m2). Median follow-up among all men who were alive at last follow-up was 6.8 years (interquartile range=3.5-11.0). During this time, 1384 men developed BCR, 117 developed CRPC and 84 died from PC. Hazard ratios were analyzed using competing-risks regression analysis accounting for non-PC death as a competing risk. RESULTS: On crude analysis, higher BMI was not associated with risk of PCSM (P=0.112), BCR (0.259) and CRPC (P=0.277). However, when BMI was categorized, overweight (hazard ratio (HR) 1.99, P=0.034) and obesity (HR 1.97, P=0.048) were significantly associated with PCSM. Obesity and overweight were not associated with BCR or CRPC (all P⩾0.189). On multivariable analysis adjusting for both clinical and pathological features, results were little changed in that obesity (HR=2.05, P=0.039) and overweight (HR=1.88, P=0.061) were associated with higher risk of PCSM, but not with BCR or CRPC (all P⩾0.114) with the exception that the association for overweight was no longer statistical significant. CONCLUSIONS: Overweight and obesity were associated with increased risk of PCSM after radical prostatectomy. If validated in larger studies with longer follow-up, obesity may be established as a potentially modifiable risk factor for PCSM.

Long-term oncological outcomes of apical positive surgical margins at radical prostatectomy in the Shared Equal Access Regional Cancer Hospital cohort.

BACKGROUND: Approximately 29-38% of all positive surgical margins (PSMs) at radical prostatectomy (RP) involve the apex. The prognostic significance of apical PSM remains unclear. We therefore compared the long-term oncologic outcomes of men with apical PSMs to those with negative PSMs, apical and other PSMs, and other PSMs at RP. METHODS: The SEARCH (Shared Equal Access Regional Cancer Hospital) database was used to identify 4031 men with prostate cancer (PCa) managed with RP with complete pathologic grade and stage data. Margin status was categorized as negative, apex only, or other positive. Multivariable Cox regression models adjusted for pathologic stage and grade were developed to test the relationship between margin status and biochemical recurrence (BCR), metastases and PCa death. RESULTS: In the final cohort, 34.3% had PSMs, whereas 65.7% had negative margins. Univariable analysis showed that compared with negative margins, apex-only PSM was associated with BCR (hazard ratio (HR): 1.4 [1.1-1.8]), but not metastases or PCa death, whereas apex and other PSMs were associated with BCR (HR: 3.3 [2.8-4]) and metastases (HR: 1.8 [1.02-3.1]) but not PCa death. Nonapical PSMs were associated with BCR (HR: 2.7 [2.4-3.1]), metastases (1.7 [1.2-2.5)] and PCa death (1.8 [1.05-3]). On multivariable analysis, apex-only, apex and other, and nonapical PSMs were associated with BCR but margin status was not associated with metastases or PCa death. CONCLUSIONS: In a large cohort of men undergoing RP, those with PSMs at the prostatic apex had lower BCR, metastases, or PCa death compared with those with PSMs at other locations. When adjusted for pathologic stage and grade, however, PSMs were associated with BCR but not long-term oncologic outcomes. These data confirm that men with apex-only PSMs may not be ideal candidates for adjuvant therapy after RP.

Do skeletal-related events predict overall survival in men with metastatic castration-resistant prostate cancer?

BACKGROUND: Skeletal-related events (SREs) including pathologic fracture, spinal cord compression, radiation to bone and surgery to bone, are common in men with bone metastatic castration-resistant prostate cancer (mCRPC). Men with mCRPC are at high risk of death. Whether SREs predict mortality is unclear. We tested the association between SREs and overall survival (OS) in a multiethnic cohort with bone mCRPC, controlling for key covariates unavailable in claims data such as bone pain, number of bone metastases and PSA doubling time (PSADT). METHODS: We collected data on 233 men diagnosed with nonmetastatic castration-resistant prostate cancer (CRPC) in 2000-2013 at two Veterans Affairs hospitals who later progressed to bone metastases. First occurrence of SRE and OS were collected from the medical records. Cox models were used to test the association between SRE and OS, treating SRE as a time-dependent variable. We adjusted for age, year, race, treatment center, biopsy Gleason, primary treatment to the prostate, PSA, PSADT, months from androgen deprivation therapy to CRPC, months from CRPC to metastasis and number of bone metastases at initial bone metastasis diagnosis. In a secondary analysis, we also adjusted for bone pain. RESULTS: During follow-up, 88 (38%) patients had an SRE and 198 (85%) died. After adjusting for risk factors, SRE was associated with increased mortality (hazard ratio (HR)=1.67; 95% confidence interval (CI) 1.22-2.30; P=0.001). When bone pain was added to the model, the association of SREs and OS was attenuated, but remained significant (HR=1.42; 95% CI 1.01-1.99; P=0.042). CONCLUSIONS: SREs are associated with increased mortality in men with bone mCRPC. Further studies on the impact of preventing SREs to increase survival are warranted.

Predicting bone scan positivity in non-metastatic castration-resistant prostate cancer.

BACKGROUND: To evaluate PSA levels and kinetic cutoffs to predict positive bone scans for men with non-metastatic castration-resistant prostate cancer (CRPC) from the Shared Equal Access Regional Cancer Hospital (SEARCH) cohort. METHODS: Retrospective analysis of 531 bone scans of 312 clinically CRPC patients with no known metastases at baseline treated with a variety of primary treatment types in the SEARCH database. The association of patients' demographics, pathological features, PSA levels and kinetics with risk of a positive scan was tested using generalized estimating equations. RESULTS: A total of 149 (28%) scans were positive. Positive scans were associated with younger age (odds ratio (OR)=0.98; P=0.014), higher Gleason scores (relative to Gleason 2-6, Gleason 3+4: OR=2.03, P=0.035; Gleason 4+3 and 8-10: OR=1.76, P=0.059), higher prescan PSA (OR=2.11; P<0.001), shorter prescan PSA doubling time (PSADT; OR=0.53; P<0.001), higher PSA velocity (OR=1.74; P<0.001) and more remote scan year (OR=0.92; P=0.004). Scan positivity was 6, 14, 29 and 57% for men with PSA<5, 5-14.9, 15-49.9 and ⩾ 50 ng ml(-1), respectively (P-trend <0.001). Men with PSADT ⩾ 15, 9-14.9, 3-8.9 and <3 months had a scan positivity of 11, 22, 34 and 47%, correspondingly (P-trend <0.001). Tables were constructed using PSA and PSADT to predict the likelihood of a positive bone scan. CONCLUSIONS: PSA levels and kinetics were associated with positive bone scans. We developed tables to predict the risk of positive bone scans by PSA and PSADT. Combining PSA levels and kinetics may help select patients with CRPC for bone scans.

Neoadjuvant chemotherapy use in bladder cancer: a survey of current practice and opinions.

Objectives. Level 1 evidence supports the use of neoadjuvant chemotherapy (NAC) to improve overall survival in muscle invasive bladder cancer; however utilization rates remain low. The aims of our study were to determine factors associated with NAC use, to more clearly define reasons for low utilization, and to determine the current rate of NAC use among urologic oncologists. Materials and Methods. Active members of the Society for Urologic Oncology were provided a 20-question survey. Descriptive statistical analysis was conducted for each question and univariate analysis was performed. Results. We achieved a response rate of 21%. Clinical T3/T4 disease was the most often selected reason for recommending NAC (87%). Concerns with recommending NAC were age and comorbidities (54%) followed by delay in surgery (35%). An association was identified between urologic oncologists who discussed NAC with >90% of their patients and medical oncologists "always" recommending NAC (P = 0.0009). NAC utilization rate was between 30 and 57%. Conclusions. Amongst this highly specialized group of respondents, clinical T3-T4 disease was the most common reason for implementation of NAC. Respondents who frequently discussed NAC were more likely to report their medical oncologist always recommending NAC. Reported NAC use was higher in this surveyed group (30-57%) compared with recently published rates.

Predicting bone scan positivity after biochemical recurrence following radical prostatectomy in both hormone-naive men and patients receiving androgen-deprivation therapy: results from the SEARCH database.

BACKGROUND: To evaluate the factors associated with positive bone scans after biochemical recurrence (BCR) following radical prostatectomy in both hormone-naive subjects and subjects after androgen-deprivation therapy (ADT). METHODS: Retrospective analysis of 380 bone scans of 301 hormone-naive subjects and 214 bone scans of 137 subjects after ADT following BCR from the Shared Equal Access Regional Cancer Hospital database. Generalized estimating equations and local regression plots were used to evaluate bone scan positivity by patients' demographics, pathological features, PSA levels and kinetics. RESULTS: Among hormone-naive subjects and subjects on ADT, bone scan positivity was seen in 24 (6%) and 65 (30%) subjects, respectively. In hormone-naive subjects, the higher prescan PSA, higher PSA velocity (PSAV) and shorter PSA doubling time (PSADT) were significantly associated with positive scans (P=0.008, P<0.001 and P<0.001, respectively). In subjects after ADT, the prescan PSA, PSAV and PSADT were significantly associated with positive scans (P=0.011, P<0.001 and P=0.002, respectively). Regression plots showed increased scan positivity with increasing PSA levels and shortening PSADT (all P<0.001) for both hormone-naive subjects and subjects after ADT. For a given PSA level and PSADT, subjects on ADT had higher bone scan positivity. CONCLUSIONS: In both hormone-naive subjects and subjects after ADT, more aggressive and advanced disease identified by higher PSA levels, higher PSAV and shorter PSADT were associated with higher bone scan positivity. For the same PSA level and PSADT, subjects after ADT had higher bone scan positivity than hormone-naive subjects. Therefore, PSA levels and kinetics may be used as selection criteria for bone scan in these patients.

Metformin does not affect risk of biochemical recurrence following radical prostatectomy: results from the SEARCH database.

BACKGROUND: While epidemiologic studies suggest that metformin use among diabetics may decrease prostate cancer (PC) incidence, the effect of metformin use on PC outcome is unclear. We investigated the association between pre-operative metformin use, dose and duration of use and biochemical recurrence (BCR) in PC patients with diabetes who underwent radical prostatectomy (RP). METHODS: We conducted a retrospective cohort analysis within the Shared Equal Access Regional Cancer Hospital (SEARCH) database of 371 PC patients with diabetes who underwent RP. Time to BCR between metformin users and non-users, and by metformin dose and duration of use was assessed using multivariable Cox proportional analysis adjusted for demographic, clinical and/or pathologic features. Time to castrate-resistant PC (CRPC), metastases and PC-specific mortality were explored as secondary outcomes using unadjusted analyses. RESULTS: Of 371 diabetic men, 156 (42%) were using metformin before RP. Metformin use was associated with more recent year of surgery (P<0.0001) but no clinical or pathologic characteristics. After adjustment for year of surgery, clinical and pathologic features, there were no associations between metformin use (hazard ratio (HR) 0.93; 95% confidence interval (CI) 0.61-1.41), high metformin dose (HR 0.96; 95% CI 0.57-1.61) or duration of use (HR 1.00; 95% CI 0.99-1.02) and time to BCR. A total of 14 patients (3.8%) developed CRPC, 10 (2.7%) distant metastases and 8 (2.2%) died from PC. Unadjusted analysis suggested that high metformin dose vs non-use was associated with increased risk of CRPC (HR 5.1; 95% CI 1.6-16.5), metastases (HR 4.8; 95% CI 1.2-18.5) and PC-specific mortality (HR 5.0; 95% CI 1.1-22.5). CONCLUSIONS: Metformin use, dose or duration of use was not associated with BCR in this cohort of diabetic PC patients treated with RP. The suggestion that higher metformin dose was associated with increased risk of CRPC, metastases and PC-specific mortality merits testing in large prospective studies with longer follow-up.

Preoperative weight change and risk of adverse outcome following radical prostatectomy: results from the Shared Equal Access Regional Cancer Hospital database.

BACKGROUND: We examined the relationship between weight change in the year before radical prostatectomy (RP) and biochemical recurrence (BCR) and adverse pathology. METHODS: We abstracted data from 359 men undergoing RP in the SEARCH (Shared Equal Access Regional Cancer Hospital) database between 2001-2007. Logistic regression and Cox proportional hazards models were used to test the association between weight change in the year before surgery and adverse pathology and BCR, respectively. RESULTS: In all, 152 (42%) men gained weight, 193 (54%) lost weight and 14 (4%) had the same weight. Among weight gainers, median gain was 2.4 kg and among weight losers, median loss was 2.7 kg. As a continuous variable, weight change was not associated with adverse pathology or BCR (all P>0.05). In secondary analysis, on multivariate analysis, men gaining ≥ 2.5 kg were at higher BCR risk (hazards ratio=1.65, 95% confidence interval (CI): 1.03-2.64, P=0.04) while weight loss ≥ 2.5 kg was not associated with BCR (hazards ratio=0.83, 95% CI: 0.54-1.29, P=0.41). CONCLUSIONS: As a continuous variable, weight change was not associated with outcome. In secondary hypothesis-generating analyses, weight gain ≥ 2.5 kg in the year before surgery, regardless of final body mass index, was associated with increased BCR following RP. If validated, these data suggest weight gain ≥ 2.5 kg may promote prostate cancer progression.

The influence of hepatic function on prostate cancer outcomes after radical prostatectomy.

Prostate growth is dependent on circulating androgens, which can be influenced by hepatic function. Liver disease has been suggested to influence prostate cancer (CaP) incidence. However, the effect of hepatic function on CaP outcomes has not been investigated. A total of 1181 patients who underwent radical prostatectomy (RP) between 1988 and 2008 at four Veterans Affairs hospitals that comprise the Shared Equal Access Regional Cancer Hospital database and had available liver function test (LFT) data were included in the study. Independent associations of LFTs with unfavorable pathological features and biochemical recurrence were determined using logistic and Cox regression analyses. Serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) levels were elevated in 8.2 and 4.4% of patients, respectively. After controlling for CaP features, logistic regression revealed a significant association between SGOT levels and pathological Gleason sum > or =7(4+3) cancer (odds ratio=2.12; 95% confidence interval=1.11-4.05; P=0.02). Mild hepatic dysfunction was significantly associated with adverse CaP grade, but was not significantly associated with other adverse pathological features or biochemical recurrence in a cohort of men undergoing RP. The effect of moderate-to-severe liver disease on disease outcomes in CaP patients managed non-surgically remains to be investigated.

The effect of race on the discriminatory accuracy of models to predict biochemical recurrence after radical prostatectomy: results from the Shared Equal Access Regional Cancer Hospital and Duke Prostate Center databases.

To evaluate whether race modifies the accuracy of nomograms to predict biochemical recurrence (BCR) after radical prostatectomy among subjects from the Shared Equal Access Regional Cancer Hospital (SEARCH) and Duke Prostate Center (DPC) databases. Retrospective analysis of 1721 and 4511 subjects from the SEARCH and DPC cohorts, respectively. The discrimination accuracy for BCR of seven previously published predictive models was assessed using concordance index and compared between African-American men (AAM) and Caucasian men (CM). AAM represented 44% of SEARCH and 14% of DPC. In both cohorts, AAM were more likely to experience BCR than CM (P<0.01). In SEARCH, the mean concordance index across all seven models was lower in AAM (0.678) than CM (0.715), though the mean difference between CM and AAM was modest (0.037; range 0.015-0.062). In DPC the overall mean concordance index for BCR across all seven nomograms was 0.686. In contrast to SEARCH, the mean concordance index in DPC was higher in AAM (0.717) than CM (0.681), though the mean differences between CM and AAM was modest (-0.036; range -0.078 to -0.004). Across all seven models for predicting BCR, the discriminatory accuracy was better among CM in SEARCH and better among AAM in DPC. The mean difference in discriminatory accuracy of all seven nomograms between AAM and CM was approximately 3-4%. This indicates that currently used predictive models have similar performances among CM and AAM. Therefore, nomograms represent a valid and accurate method to predict BCR regardless of race.

Preoperative predictors of blood loss at the time of radical prostatectomy: results from the SEARCH database.

The literature contains conflicting data on preoperative predictors of estimated blood loss (EBL) at radical retropubic prostatectomy (RRP). We sought to examine preoperative predictors of EBL at the time of RRP among patients from the SEARCH database to lend clarity to this issue. A total of 1154 patients were identified in the SEARCH database who underwent RRP between 1988 and 2008 and had EBL data available. We examined multiple preoperative factors for their ability to predict EBL using multivariate linear regression analysis. Median EBL was 900 ml (s.d. 1032). The 25th and 75th percentile for EBL were 600 and 1500 ml, respectively. EBL increased significantly with increasing body mass index (BMI) and increasing prostate size and decreased with more recent year of RRP (all P<0.001). The mean-adjusted EBL in normal-weight men (BMI<25 kg/m(2)) was 807 ml compared to 1067 ml among severely obese men (BM I>or=35 kg/m(2)). Predicted EBL for men with the smallest prostates (<20 g) was 721 ml, compared to 1326 ml for men with prostates >or=100 g. Finally, statistically significant differences between centers were observed, with mean-adjusted EBL ranging from 844 to 1094 ml. Both BMI and prostate size are predictors of increased EBL. Prostate size is of particular note, as a nearly twofold increased EBL was seen from the smallest (<20 g) to the largest prostates (>or=100 g). Over time, average EBL significantly decreased. Finally, significant differences in EBL were observed between centers. Patients with multiple risk factors should be forewarned they are at increased risk for higher EBL, which may translate into a greater need for blood transfusion.

Impact of nerve sparing on surgical margins and biochemical recurrence: results from the SEARCH database.

The effects of nerve sparing on the risk of positive surgical margins (PSMs) and biochemical recurrence after radical prostatectomy (RP) remain controversial. We examined data from 1018 men treated by RP between 1988 and 2006 at five centers in the Shared Equal Access Regional Cancer Hospital database. Neither bilateral nor unilateral nerve-sparing techniques were associated with a higher risk of PSM; on multivariate analysis of individual sides, the risk of PSM on either side was not increased by nerve sparing on either side. The risk for biochemical recurrence was not affected by bilateral or unilateral nerve sparing. When used on appropriately selected patients, nerve sparing does not increase the probability of PSM or biochemical recurrence after RP.

Prostate cancer mortality rates compared to urologist population densities and prostate-specific antigen screening levels on a state-by-state basis in the United States of America.

We hypothesized that prostate cancer screening and availability of urologists among states may be associated with reduced prostate cancer mortality in the United States. To test this hypothesis, state-specific prostate cancer mortality rates for white males were compared to urologist population densities and prostate-specific antigen (PSA) screening rates on a state-by-state basis. The urologist population density was calculated by dividing the number of urologists per state by the population. We found that prostate cancer mortality rates correlated inversely with urologist population densities (P<0.01) and PSA screening (P<0.01) suggesting that screening and treatment reduce prostate cancer mortality.

A prospective randomized comparison of extensive prostate biopsy to standard biopsy with assessment of diagnostic yield, biopsy pain and morbidity.

In a prospective randomized study, we compare standard prostate biopsy to extensive biopsy utilizing intravenous conscious sedation (IVCS). Initial biopsy patients (n=197) were randomized to either standard biopsy using intrarectal lidocaine gel (6-12 biopsies, mean 10.1) or extensive biopsy (24 biopsies) using IVCS. Cancer detection and urinary symptoms were no different between groups. However, biopsy pain was rated significantly lower and satisfaction significantly higher in the extensive biopsy group. Temporary urinary retention occurred in 4% of the extensive biopsy group. Extended biopsy with 24 samples does not improve cancer detection compared to standard biopsy when 10 cores are obtained. Extensive biopsy is very well tolerated and associated with less pain and more satisfaction than standard biopsy.

Is there a difference in outcome after radical prostatectomy between patients with biopsy Gleason sums 4, 5, and 6? Results from the SEARCH database.

PURPOSE: Fewer patients newly diagnosed with prostate cancer today have biopsy Gleason sums <6 compared to several years ago. Several tables and nomograms for predicting disease recurrence after definitive therapy provide little or no discrimination between biopsy Gleason sums 4, 5, and 6. We sought to examine the significance of biopsy Gleason sum for predicting biochemical failure following radical prostatectomy (RP) for men with biopsy Gleason sums of 4, 5, and 6. MATERIALS AND METHODS: We examined data from 988 men treated with RP between 1988 and 2002 who had biopsy Gleason sums of 4-6. Clinical and pathological variables as well as outcome information were compared between men with biopsy Gleason sums of 4-6. The log-rank and Cox proportional hazards analysis were used to determine whether biopsy Gleason sum provided unique prognostic information for men with low biopsy Gleason sums undergoing RP. RESULTS: There was statistically significant, but overall weak correlation between biopsy Gleason sum and Gleason sum of the RP specimen (Spearman's r=0.277, P<0.001). As biopsy Gleason sum increased from 4 to 5 to 6, there was a steady rise (HR=1.31 for each one point increase in Gleason sum, Cox's model) in the risk of PSA failure (P=0.025, log-rank). On multivariate analysis comparing biopsy Gleason sum, preoperative PSA, clinical stage, year of surgery, percent of biopsy cores positive, and age for their ability to predict time to biochemical recurrence, only PSA (HR 2.09, CI 1.56-2.80, P<0.001) and biopsy Gleason sum (HR 1.33, CI 1.05-1.70, P=0.019) were significant independent predictors of PSA failure. CONCLUSIONS: Despite weak correlation between biopsy and pathologic Gleason sum among men with biopsy Gleason sum 4-6 tumors, grade was a significant independent predictor of PSA failure following RP. In the range of 4-6, biopsy Gleason sum acted as a continuous variable for predicting PSA failure. The routine use of Gleason sums 4 and 5 to grade prostate needle biopsy specimens should not be abandoned.

Use of early PSA velocity to predict eventual abnormal PSA values in men at risk for prostate cancer.

The purpose of this study was to determine if early PSA velocity (EPSAV), drawn from PSA values within normal ranges, predicts the later occurrence of abnormally high PSA values or positive prostate biopsy early enough to be clinically beneficial. Early PSAV (ng/ml/y) calculated from two normal PSA readings was tested to predict later PSA exceeding 4 ng/ml (1551 evaluable patients) or 10 ng/ml (1905 evaluable patients) and positive prostate biopsy. The time from EPSAV to develop abnormal PSA was recorded.A post-EPSAV PSA>4 ng/ml was reached by 367 patients and >10 by 293. EPSAV was significantly different (P<0.001) between patients whose PSA did or did not reach the PSA cut-off point and also significantly predicted a positive biopsy result (P<0.001). EPSAV predicted abnormal PSA more than 1 y in advance in 68 and 52% of the PSA 4 and 10 ng/ml cut-off point groups, respectively. Early PSAV from normal PSA readings may allow early detection of men at risk for prostate cancer. This may help identify men for earlier prostate biopsy or for less frequent PSA monitoring.

Initiation of salvage therapy for prostate cancer.

Physicians and patients have variable and individual levels of comfort regarding when to begin salvage therapy for rising prostate specific antigen (PSA) after definitive treatment of prostate cancer. The decision to start salvage therapy is a multifactorial process for which few rigorous data or guidelines exist. A questionnaire survey of urologists of the Department of Defense (DoD) Center for Prostate Disease Research (CPDR) was undertaken to obtain current perspectives on when to begin salvage therapy for biochemical failure after definitive therapy. Variables of age, grade, T-stage, nodal status, performance status, latency since prior therapy, PSA velocity, and ploidy were prioritized in four clinical situations; subsequent questions assessed consensus PSA cut-offs for beginning adjuvant therapy in 84 clinical scenarios. Consensus on PSA cut-off points was limited to postoperative radiotherapy (RT), where values of 1.0-1.5 were the mean cut-off points. CPDR urologists consider salvage prostatectomy post-RT only for patients <70-y-old with node negative, grade 2-7 disease and excellent performance status. Ploidy was not generally considered useful in any scenario. Many variables in addition to PSA level are involved in the decision of when to commence adjuvant therapy for initial biochemical failure. These are strikingly interdependent, and few clear absolutes are evident from this questionnaire. This is a point of necessary further research and continued discussion among physicians caring for these patients.

Relationship between obesity and race in predicting adverse pathologic variables in patients undergoing radical prostatectomy.

OBJECTIVES: To determine whether obesity is associated with more advanced prostate cancer (PCa) in radical prostatectomy patients and to explore the ethnic variability in body mass index (BMI) as a potential explanation for racial differences in PCa risk. METHODS: A multi-institutional retrospective analysis of the clinical and pathologic parameters was performed on data from 860 patients with PCa undergoing radical prostatectomy between 1992 and 1998. Patient height and weight was used to calculate the BMI, which categorized patients into obese (BMI 30 kg/m(2) or greater), overweight (BMI 25 to 30 kg/m(2)), and normal (BMI 25 kg/m(2) or less) groups. Age, serum prostate-specific antigen level, pathologic stage, and Gleason score for each group were compared. The distribution of the BMI in each of four ethnic groups was also determined. RESULTS: Of 860 patients, 171 (20%) were obese, 425 (49%) overweight, and 264 (31%) normal. The obese patients presented at a younger mean age (62 years, P = 0.001), had higher mean Gleason scores (6.7, P = 0.002), had a higher likelihood of Gleason score 7 or greater cancer (71%, P = 0.003), and had a lower chance of organ-confined cancer (46%, P = 0.050). The BMI was highest in blacks, followed by whites and Asians, and blacks had significantly higher grade cancers (P = 0.045). In multiple logistic regression analysis of the BMI and race, only BMI remained an independent predictor of Gleason grade. CONCLUSIONS: Obese patients with PCa present for radical prostatectomy at a younger age with higher grade and more pathologically advanced cancers. Blacks have higher grade cancers than other ethnic groups and, at the same time, have significantly higher BMIs. These findings suggest that obesity may in part account for the racial variability in PCa risk.