Impact of obesity on prostate cancer recurrence after radical prostatectomy: data from CaPSURE

Insulin-like growth factor pathway: a link between androgen deprivation therapy (ADT), insulin resistance, and disease progression in patients with prostate cancer?

Androgen deprivation therapy (ADT) is standard of care for patients with metastatic hormone-sensitive prostate cancer (HSPC), yet through its induction of a hypogonadal state leads to metabolic perturbations, including insulin resistance (IR) and obesity. IR and obesity have been associated with an increased risk of progression to castrate-resistant prostate cancer (CRPC) and ultimately increased prostate cancer-specific mortality. On a molecular level, this association between obesity/IR and prostate cancer progression may be mediated by alterations in the insulin-like growth factor (IGF) axis, which has been shown to be up-regulated upon disease progression to CRPC. Targeting the IGF axis, either by anti-IGF therapy or via enhancement of peripheral insulin sensitivity, represents a viable therapeutic target in patients with prostate cancer. Using the development of IR and/or obesity may represent a clinically available biomarker that may predict those patients most likely to respond to such therapy, and warrants testing in future prospective clinical trials.

The interaction of body mass index and race in predicting biochemical failure after radical prostatectomy

STUDY TYPE

Therapy (case series).

LEVEL OF EVIDENCE

4

OBJECTIVE

To examine the interaction of body mass index (BMI) and race in predicting biochemical failure (BCF) after radical prostatectomy (RP). The relative contribution of BMI and race to BCF after RP has not been well characterized.

PATIENTS AND METHODS

From 1988 to 2008, 969 white and black men underwent RP and BMI data were available. In all, 168 (17.3%) were black and 801 (82.7%) were white men. BCF was defined as a post-surgery PSA level≥0.2 ng/mL on ≥2 measurements. Cox regression methods were used to model the relationship between race, BMI and BCF.

RESULTS

The 969 men had a mean age of 59.8±7.2 years. There was no significant difference in BMI between black and white men (P=0.32). The 5-year disease-free survival for black obese men was the lowest at 48%, compared with non-obese black (73%), obese white (82%) and non-obese white men (83%, P<0.001). BMI did not have a significant impact on BCF. In a multivariate analysis, black race remained an independent predictor of BCF [hazard ratio (HR)=1.76, P=0.01]. BMI does not affect the risk of BCF in black men differently than white men (P value for interaction 0.93).

CONCLUSIONS

Black race is an independent predictor of biochemical failure after adjusting for pathological factors. The impact of BMI on BCF did not vary among different races. These findings suggest that elevated BMI does not affect the BCF rates of black men more than in other races, and that other factors may influence the racial variability in disease-free survival and BCF risk.

Weight gain is associated with an increased risk of prostate cancer recurrence after prostatectomy in the PSA era

Although obesity at the time of prostatectomy has been associated with prostate cancer recurrence, it is unknown whether obesity before or after surgery, or weight change from the years prior to surgery to after surgery is associated with recurrence. Thus, we examined the influence of obesity and weight change on recurrence after prostatectomy. We conducted a retrospective cohort study of 1,337 men with clinically localized prostate cancer who underwent prostatectomy performed during 1993-2006 by the same surgeon. Men self-reported weight and physical activity at 5 years before and 1 year after surgery on a survey during follow-up. Mean follow-up was 7.3 years. We estimated multivariable-adjusted HRs of prostate cancer recurrence comparing obesity at 5 years before and at 1 year after surgery with normal weight, and a gain of more than 2.2 kg from 5 years before to 1 year after surgery with stable weight. During 9,797 person years of follow-up, 102 men recurred. Compared with men who had stable weight, those whose weight increased by more than 2.2 kg had twice the recurrence risk (HR = 1.94; 95% CI, 1.14-3.32) after taking into account age, pathologic stage and grade, and other characteristics. The HR of recurrence was 1.20 (95% CI, 0.64-2.23) and 1.72 (95% CI, 0.94-3.14) comparing obesity at 5 years before and at 1 year after surgery, respectively, with normal weight. Physical activity (≥ 5 h/wk) did not attenuate risk in men who gained more than 2.2 kg. By avoiding weight gain, men with prostate cancer may both prevent recurrence and improve overall well-being.

Body mass index, prostate cancer-specific mortality, and biochemical recurrence: a systematic review and meta-analysis

Increasing evidence suggested obesity, measured by body mass index (BMI), was associated with prostate cancer-specific mortality, and its impact on biochemical recurrence was also inconclusive. We systematically searched MEDLINE, EMBASE, and bibliographies of retrieved studies up to January 5, 2010. We used random-effects meta-analysis to assess the relative risks (RR) of prostate cancer-specific mortality and biochemical recurrence associated with a 5 kg/m(2) increase in BMI. Among the six population-based cohort studies in 1,263,483 initially cancer-free men, 6,817 prostate cancer deaths occurred; a 5 kg/m(2) increase in BMI was associated with 15% (RR: 1.15, 95% confidence interval (CI): 1.06-1.25, P < 0.01) higher risk of dying of prostate cancer. In the six postdiagnosis survival studies on 18,203 patients with 932 prostate cancer deaths, a 5 kg/m(2) increase in BMI was associated with 20% higher prostate cancer-specific mortality (RR: 1.20, 95% CI: 0.99-1.46, P = 0.06). In the sixteen studies which followed 26,479 prostate cancer patients after primary treatment, a 5 kg/m(2) increase in BMI was significantly associated with 21% increased risk of biochemical recurrence (RR: 1.21, 95% CI: 1.11-1.31 P < 0.01). Elevated BMI is associated with risk of prostate cancer-specific mortality in prospective cohort studies and biochemical recurrence in prostate cancer patients. Its association with prostate cancer-specific mortality in diagnosed patients needs to be further evaluated.

Body mass index is not a predictor of biochemical recurrence after radical prostatectomy in Dutch men diagnosed with prostate cancer

PURPOSE

To determine the effect of body mass index (BMI) on clinical and pathological characteristics at time of diagnosis and on risk of biochemical recurrence after radical prostatectomy among Dutch men diagnosed with prostate cancer.

METHODS

In total, 1,116 prostate cancer patients with known BMI, diagnosed between 2003 and 2006, were identified from the population-based cancer registry held by the Comprehensive Cancer Centre East, The Netherlands. Of these, 504 patients underwent a radical prostatectomy. Patients were categorized as normal weight (BMI < 25 kg/m(2)), overweight (BMI 25-30 kg/m(2)), or obese (BMI ≥ 30 kg/m(2)). Multivariable proportional hazards regression models, adjusted for age, prediagnostic PSA levels, and pathological characteristics were used to evaluate BMI as a prognostic factor for biochemical recurrence after radical prostatectomy.

RESULTS

Overall, clinical and biopsy characteristics did not significantly differ among BMI groups. Pathological characteristics after radical prostatectomy did not significantly differ among BMI groups, except for tumor stage, which was highest in obese patients (P = 0.017). For patients treated with radical prostatectomy, 5-year risk (95% Confidence Intervals) of biochemical recurrence was 30% (23-37%) for normal weight, 32% (25-39%) for overweight, and 25% (9-41%) for obese patients (log rank P = 0.810). BMI was not an independent prognostic factor for biochemical recurrence in multivariable proportional hazards regression analyses (HR 0.99 per kg/m(2), 95% CI: 0.93-1.06).

CONCLUSIONS

Compared with non-obese men, pathological tumor stage tended to be higher in obese men. Clinical relevance of this finding is unclear, because BMI was not an independent predictor of biochemical recurrence after radical prostatectomy.

Periprostatic fat correlates with tumour aggressiveness in prostate cancer patients

STUDY TYPE

Prognostic (case series).

LEVEL OF EVIDENCE

4. What's known on the subject? and What does the study add? Nowadays more and more publications have been published about the topic prostate cancer aggressiveness and obesity with mixed results. However, most of the publications used the BMI as a marker for obesity, while the most metabolic active fat is the visceral fat. To learn more about these relations we measured and used the visceral fat in our paper.

OBJECTIVE

To examine if the periprostatic fat measured on computed tomography (CT) correlates with advanced disease we examined patients who received radiotherapy for localized prostate cancer. Several USA reports found a positive association between obesity and prostate cancer aggressiveness. However, in recent European studies these conclusions were not confirmed. Studies concerning this issue have basically relied on body mass index (BMI), as a marker of general obesity. Visceral fat, however, is the most metabolically active and best measured on CT.

PATIENTS AND METHODS

In 932 patients, who were treated with external radiotherapy (N=311) or brachytherapy (N=621) for their T1-3N0M0 prostate cancer, different fat measurements (periprostatic fat, subcutaneous fat thickness) were performed on a CT. Associations between the different fat measurements and risk of having high-risk (according to Ash et al., PSA>20 or Gleason score≥8 or T3) disease was measured.

RESULTS

The median age (IQR) was 67.0 years (62.0-71.0) and median BMI (IQR) was 25.8 (24.2-28.3). Logistic regression analyses, adjusted for age, revealed a significant association between periprostatic fat density (PFD) and risk of having a high risk disease. (Odds ratio [95% CI] 1.06 [1.04-1.08], P<0.001)

CONCLUSION

Patients with a higher PFD had more often aggressive prostate cancer.

Body mass index adjusted prostate-specific antigen and its application for prostate cancer screening

OBJECTIVES

The prostate cancer prevention trial (PCPT) prostate cancer risk calculator was developed to aid physicians in counseling men for consideration of prostate biopsy based on prostate-specific antigen (PSA) and other clinical risk factors. This study investigated the role of body mass index (BMI) in this assessment.

MATERIALS AND METHODS

BMI category was defined as < 25 (under/normal weight), 25.0-29.9 (overweight), 30.0-34.9 (obese [OB] I), 35.0-39.9 (OB II), and ≥ 40 (OB III). BMI-adjusted PSA for a man was determined by multiplying his PSA to the ratio of the geometrical mean of PSA for BMI < 25 to the geometrical mean of PSA for his BMI category. Operating characteristics of PSA and BMI-adjusted PSA were compared with PCPT risks using area underneath the receiver operating characteristic curve (AUC). Statistical tests of differences between AUCs for different diagnostic tests were performed with the nonparametric U-statistic method.

RESULTS

BMI-adjusted PSA equaled to unadjusted PSA multiplying 1.09, 1.20, 1.50, and 1.71 for men in overweight, OBI, OBII, and OBIII categories, respectively. The AUC for BMI-adjusted PSA values (0.84) did not differ from PSA; that of the PCPT calculator with BMI-adjusted PSA (0.87) did not differ from the calculator with PSA. Of 2816 men with a PSA less than or equal to 2.5 ng/mL who did not undergo biopsy, 126 (4.5%) would have a BMI-adjusted PSA exceeding 2.5 ng/mL.

CONCLUSIONS

Because of lower levels of PSA, overweight and obese men may have diminished cancer detection opportunities when undergoing PSA-based screening.

The relationship between adiposity and gleason score in men with localized prostate cancer

BACKGROUND

We investigated the relationship between body mass index (BMI) at the time of cancer diagnosis and malignant phenotype as measured by Gleason score.

METHODS

This was a population-based cross-sectional study conducted on 1,096 prostate cancer patients treated for cure in Ontario, Canada between 1990 and 1998. An electronic-linked data set was enhanced by retrospective chart review. BMI was categorized as: normal (BMI <25.0), overweight (BMI 25.0-29.9), and obese (BMI ≥30). We also investigated the role of diabetic status. Gleason scores were categorized as: 2-4, 5-6, 7, and 8-10. We assessed the effect modification by patient age.

RESULTS

BMI was not associated with Gleason score; 9.7% of those with normal BMI had a Gleason score ≥8, and 9.4% fell into this Gleason category in both the overweight and obese groups (P = 0.73). 11.7% of diabetics had a Gleason score ≥8 compared to 9.3% in the non-diabetic group (P = 0.79). Both of these results persisted in a multivariate analysis controlling for age and diagnosis year. When stratified by age, only the Gleason score distribution in the youngest cohort (50- to 59-year olds) indicated higher Gleason scores in the obese group, with marginally significant results (P = 0.16).

CONCLUSIONS

With a possible exception in younger men, elevated BMI at the time of diagnosis does not appear to be associated with aspects of aggressive behavior associated with Gleason grade. The effect of adiposity on prostate cancer outcome is complex, requiring further study that includes attention to factors such as length of exposure, concomitant co-morbidities, and ethnicity.

Is body mass index associated with pathological outcomes after radical prostatectomy in Korean men?

Study Type--Therapy (case series) Level of Evidence 4. What's known on the subject? and What does the study add? Today, controversies continue with regards to the potential impact of obesity or increased body mass index (BMI) on actual pathological features of prostate cancer and/or clinical outcome after radical prostatectomy (RP). Moreover, a paucity of relevant data exist in the literature regarding Asian or Korean men. For the first time to our knowledge, the study demonstrated that although higher BMI was significantly associated with extracapsular extension of tumour, BMI did not significantly enhance ability to preoperatively predict extracapsular extension of tumour and was not significantly associated with PSA outcome as well as other objective pathological outcomes in Korean men undergoing RP, who are generally leaner than Western counterparts.

OBJECTIVE

• To investigate the impact of increased body mass index (BMI) on pathological features after radical prostatectomy (RP) in Korean patients.

PATIENTS AND METHODS

• We reviewed the records of 1000 Korean patients who underwent RP for prostate cancer and assessed the differences in pathological outcomes and biochemical recurrence-free survival after RP according to BMI of subjects via univariate and multivariate analyses. • A multivariate logistics regression model, the performance of which was analysed from a receiver operator characteristics curve, was applied to assess the predictive capacity of variables shown to be significant predictors of adverse pathological outcome.

RESULTS

• Among our subjects, only 17 (1.7%) men had BMI ≥30 kg/m(2). After adjusting for various clinical variables, BMI (highest quartile vs others) was shown to be significantly associated with extracapsular extension of tumour (P= 0.014) and positive surgical margin (P= 0.019), but not with high pathological Gleason score (P= 0.912) and seminal vesicle invasion (P= 0.191). • Meanwhile, the addition of BMI to a multivariate model devised for preoperatively predicting extracapsular extension of tumour did not significantly increase predictive accuracy of the model (P= 0.319). On multivariate analysis, BMI was not shown to be a significant predictor of biochemical recurrence-free survival (P= 0.201).

CONCLUSION

• Although higher BMI was significantly associated with extracapsular extension of tumour, BMI did not significantly enhance the ability to preoperatively predict extracapsular extension of tumour and was not significantly associated with PSA outcome or with other objective pathological outcomes in Korean men undergoing RP, who are generally leaner than their western counterparts.

The relationship between body mass index and thyroid cancer pathology features and outcomes: a clinicopathological cohort study

BACKGROUND

Obesity has been implicated as a predisposing and disease-modifying factor in cancer. Epidemiological studies suggest that obesity is associated with an increased risk of thyroid cancer; however, the relationships between obesity and thyroid cancer stage or behavior are uncertain. We hypothesized that a higher body mass index (BMI) would be associated with aggressive thyroid cancer features and a higher incidence of persistent/recurrent disease.

METHODS

Two hundred fifty-nine consecutive patients with thyroid cancer were enrolled in this retrospective cohort study. Histopathological tumor features, stage at diagnosis, and disease status during and at the end of the study were determined based on chart review. BMI was calculated at the first clinical visit to our institution. The relationships between BMI and these parameters were assessed.

RESULTS

Mean follow-up time for the group was 6.2 yr (0.11-46 yr). No positive associations were identified between BMI and T, N, or M stage at diagnosis, vascular invasion, or recurrent or persistent disease on univariate or multivariate analyses. The absence of an association was also demonstrated on analysis by BMI quartiles. An unexpected inverse association was identified between BMI and nodal metastasis and tumor invasion on both univariate and multivariate analyses, suggesting that obesity may be associated with less aggressive tumor features, a finding that requires confirmatory studies.

CONCLUSION

Although obesity has been associated with increased thyroid cancer incidence, a higher BMI was found not to be associated with more aggressive tumor features or a greater likelihood of recurrence or persistence over the analyzed time period.

Effects of dietary fat on spontaneous metastasis of Lewis lung carcinoma in mice

The present study assessed the effects of dietary fat on spontaneous metastasis of Lewis lung carcinoma in mice. Three-week old male C57BL/6 mice were fed the AIN-93G diet or a 45% fat diet (% kcal.) for 7 weeks before they were subcutaneously injected with 2.5 × 10⁵ viable carcinoma cells. The primary tumor was resected 2 weeks later, and mice were maintained on their respective diets for an additional 2 weeks. The high-fat diet significantly increased body weight and abdominal adipose weight compared to the AIN-93G diet. Feeding mice the 45% fat diet resulted in a two-fold increase in the number of lung metastases (P < 0.05), a 35% increase in tumor cross-sectional area, and a 50% increase in tumor volume compared to mice fed the AIN-93G diet. There were no differences in plasma concentrations of TIMP-1, IL-1β, VEGF and MCP-1 in non-tumor-bearing mice fed the AIN-93G diet or the high-fat diet, but significant increases in these cytokines in tumor-bearing mice fed the AIN-93G diet compared to the non-tumor-bearing mice fed the same diet (P < 0.05 for each comparison). Further significant increases in these cytokines in tumor-bearing mice fed the 45% fat diet compared to the same tumor-bearing mice fed the AIN-93G diet (P < 0.05 for each comparison). The high-fat diet significantly increased plasma leptin and significantly decreased plasma adiponectin compared to the AIN-93G diet in both non-tumor-bearing and tumor-bearing mice. Results of the present study demonstrated that the high-fat diet enhanced spontaneous metastasis of Lewis lung carcinoma in mice and that this aggressiveness was accompanied with significant increases in plasma concentrations of angiogenic cytokines, suggesting that dietary fat affects metastasis by promoting angiogenic processes.

Energetics in colorectal and prostate cancer

For decades, extensive research has explored the association between factors related to energy balance and the development of both colorectal cancer and prostate cancer. Physical inactivity, obesity, higher red meat consumption or Western pattern diet, insulin and insulin-like growth factors (IGFs) appear to increase the risk of colorectal cancer while obesity, high animal fat intake, insulin and IGFs have been associated with increasing prostate cancer risk and/or aggressiveness. Recently, there are growing observational data on the relationship between energetic host factors and progression of these cancers. While there are no large randomized trials in either colorectal cancer or prostate cancer assessing these factors on disease progression or disease-related mortality, the data supporting associations between some of these factors and colorectal or prostate cancer survivorship are getting more compelling. This article will evaluate the emerging data on energy balance in patients with colorectal or prostate cancer.

An exploratory study of the factors that influence physical activity for prostate cancer survivors

PURPOSE

To gain an understanding of the factors that influence participation in physical activity for survivors of prostate cancer and to examine changes in participation in physical activity pre- and post-diagnosis.

METHODS

Eighteen men who had completed treatment for prostate cancer 6 months prior were interviewed for this study. Constant comparison was used to examine the main themes arising from the interviews.

RESULTS

Barriers to physical activity tended not to be related to the physical side effects of treatment, however lack of confidence following treatment, co-morbidities, older age physical decline and lack of time were barriers. Motivations for physical activity included psychological benefits, physical benefits, and the context of the activity. Participants did not recall receiving information about physical activity from clinicians and few were referred to exercise specialists. Physical activity 6 months post-treatment was similar to physical activity levels prior to diagnosis, although there was some decline in terms of the intensity of participation.

CONCLUSIONS

Interventions to increase physical activity for this group will need to take into account co-morbidities and decline associated with older age, as well as treatment side effects and psychological issues associated with a cancer diagnosis. Encouragement from health care professionals and referral to an exercise specialist is likely to give men more confidence to participate in physical activity.

Radical prostatectomy in obese patients: Improved surgical outcomes in recent years

OBJECTIVES

Obesity has been proposed as a risk factor for reduced disease-specific survival, increased positive surgical margin (PSM) and biochemical recurrence (BCR) after radical prostatectomy (RP) in patients with prostate cancer. The aim of this study was to clarify the relationship between obesity and surgical outcomes in patients undergoing RP.

METHODS

Medical records of 491 patients who underwent RP from 2004 to 2007 were retrieved from our institutional database. Patients were divided into three groups based on their body mass index (BMI): <25, 25-30 (overweight) and >30 kg/m (obese). Outcomes after RP were compared between the groups in terms of length of stay, perioperative complications, BCR, PSM and Gleason scores.

RESULTS

Age, stage and preoperative prostate-specific antigen were similar between BMI categories. Operating time was prolonged in obese patients (146 vs 135 min, P = 0.01) and blood loss was greater (mean estimated blood loss 640 vs 504 mL, P = 0.02), but did not translate into higher transfusion rates. Early complication rates, PSM rates and Gleason scores were not statistically different between the groups. Significant differences in late outcomes, such as the need for adjunct procedures or BCR (hazard ratio 0.44, 95% CI 0.18-1.09), were not shown.

CONCLUSION

As surgical experience with high BMI patients has developed, RP appears to be a well tolerated procedure in contemporary series, irrespective of BMI. In particular, early outcome parameters, such as PSM and BCR rates, are similar.

Diabetes and outcomes after radical prostatectomy: are results affected by obesity and race? Results from the shared equal-access regional cancer hospital database

BACKGROUND

Diabetes is associated with lower prostate cancer risk. The association of diabetes with prostate cancer outcomes is less clear. We examined the association between diabetes and outcomes after radical prostatectomy and tested whether associations varied by race and/or obesity.

MATERIALS AND METHODS

This study is a retrospective analysis of 1,262 men treated with radical prostatectomy between 1988 and 2008 within the Shared Equal-Access Regional Cancer Hospital database. We examined the multivariate association between diabetes at surgery and adverse pathology, biochemical recurrence (BCR), and prostate-specific antigen doubling time at recurrence using logistic, proportional hazards, and linear regression, respectively. Data were examined as a whole and stratified by race and obesity.

RESULTS

Diabetes was more prevalent among black (22% versus 15%, P < 0.001) and more obese men (P < 0.001). Diabetes was associated with higher tumor grade (odds ratio, 1.73; P = 0.002), seminal vesicle invasion (odds ratio, 1.73; P = 0.04), but not BCR (P = 0.67) or PSADT at recurrence (P = 0.12). In the secondary analysis, among white obese men, diabetes was associated with 2.5-fold increased BCR risk (P = 0.002) and a trend toward shorter PSADT, whereas among all other men (nonobese white men and black men), diabetes was associated with 23% lower recurrence risk (P = 0.09) and longer PSADT (P = 0.04).

CONCLUSION

In a radical prostatectomy cohort, diabetes was not associated with BCR. In the secondary analysis, diabetes was associated with more aggressive disease in obese white men and less aggressive disease for all other subsets. If externally validated, these findings suggest that among men with prostate cancer, the association between diabetes and prostate cancer aggressiveness may vary by race and obesity.

Obesity as a predictor of adverse outcome across black and white race: results from the Shared Equal Access Regional Cancer Hospital (SEARCH) Database

BACKGROUND

Across multiple studies, obesity has been associated with an increased risk of higher grade disease and prostate-specific antigen (PSA) recurrence after radical prostatectomy (RP). Whether these associations vary by race is unknown. In the current study, the authors examined the association between obesity and outcome after RP stratified by race.

METHODS

A retrospective analysis was performed on 1415 men in the Shared Equal Access Regional Cancer Hospital (SEARCH) database who underwent RP between 1989 and 2008. The association between increased body mass index (BMI) and adverse pathology and biochemical recurrence was examined using multivariate logistic regression and Cox models, respectively. Data were examined stratified by race.

RESULTS

After adjusting for preoperative clinical characteristics, higher BMI was associated with higher tumor grade (P = .008) and positive surgical margins (P < .001) in white men, and similar but statistically nonsignificant trends were observed in black men. No significant interaction was noted between race and BMI for associations with adverse pathology (P(interaction)> or =.12). After adjusting for preoperative clinical characteristics, higher BMI was associated with an increased risk of recurrence in both white men (P = .001) and black men (P = .03). After further adjusting for pathologic variables, higher BMI was associated with significantly increased risk of recurrence in white men (P = .002) and black men (P = .01). No significant interactions were observed between race and BMI for predicting biochemical progression adjusting either for preoperative factors (P(interaction) = .35) or for preoperative and pathologic features (P(interaction) = .47).

CONCLUSIONS

Obesity was associated with a greater risk of recurrence among both black men and white men. Obesity did not appear to be more or less influential in 1 race than another but, rather, was identified as a risk factor for aggressive cancer regardless of race.

Diet, physical activity and energy balance and their impact on breast and prostate cancers

Obesity, physical activity status and circulating levels of sex steroid hormones and growth factor proteins are intrinsically linked to energy balance. Epidemiological studies have previously reported associations between these factors and the risk of hormone-related cancers such as prostate and breast cancer in men and postmenopausal women. An increasing number of intervention studies in 'at-risk' populations and cancer survivors are now investigating the effects of lifestyle interventions that promote negative energy balance on circulating levels of sex hormones and growth factor proteins as surrogate markers of cancer risk. Evidence from these studies suggests that lifestyle interventions can improve insulin sensitivity, alter the balance of circulating sex steroid hormones and insulin-like growth factor (IGF) axis proteins (including IGF-1 and the IGF binding proteins 1 and 3) and change the functioning of immune cells in peripheral blood. Such changes could influence the risk of developing hormone-related cancers, as well as having the potential to improve disease-free survival in patients recovering from cancer treatment. However, despite promising results, the methodological quality of most intervention studies has been limited due to small subject numbers, lack of adequate control groups or non-randomised designs and the absence of long-term follow-up measures. More intervention studies with randomised controlled designs, higher numbers of subjects and longer-term follow-up measures are needed to establish which combination of specific dietary and physical activity interventions work best for reducing risk in 'at-risk' populations and survivors, optimal dose-response relationships and the magnitude of change in surrogate markers of cancer risk that is required to induce a protective effect.

Body mass index is not a prognostic marker for prostate-specific antigen failure and survival in Dutch men treated with brachytherapy

OBJECTIVE

To examine the relationship between body mass index (BMI) and biochemical recurrence (BCR), cancer-specific (CSS) and overall survival (OS) in men treated with permanent prostate brachytherapy (PPB), as there is limited information on the affect of obesity on treatment outcomes for prostate cancer.

PATIENTS AND METHODS

In all, 1530 patients with clinically localized prostate cancer who underwent PPB were studied. Clinical and pathological data were retrospectively obtained from medical records. The BMI was classified as normal (< 25 kg/m(2)), overweight (25-30 kg/m(2)) and obese (> or = 30 kg/m(2)). BCR was defined as a rise in PSA levels of > or = 2 ng/mL after the nadir had been reached. The cause of death was determined for each deceased patient. Patients with metastatic prostate cancer who died of any cause were classified as prostate cancer deaths. RESULTS In all, 617 (40%) patients were classified as having a normal weight, 754 (49%) overweight and 159 (10%) were obese. The Kaplan-Meier 8-year risk of BCR (95% confidence interval) was 33.3% (27.2-39.4), 29.2% (23.5-34.9) and 29.3% (12.4-46.2) for patients with a BMI of < 25 kg/m(2), 25-30 kg/m(2) and > or = 30 kg/m(2), respectively. The 8-year CSS was 88.2% (83.1-93.3), 88.6% (83.7-93.5) and 90.6% (79.9-101.4) and the 8-year OS was 70.1% (63.6-76.6), 72.9% (66.6-79.2) and 81.8% (69.3-94.3) for these three groups, respectively. Multivariate proportional hazard regression analyses of BMI and established prognostic factors for BCR confirmed the absence of any prognostic value of BMI on BCR, CSS and OS.

CONCLUSIONS

BMI did not appear to have any prognostic value for BCR, CCS or OS in patients with clinically localized prostate cancer treated with PPB.

The impact of obesity on overall and cancer specific survival in men with prostate cancer

PURPOSE

We examined the impact of obesity on disease specific and overall survival in patients with prostate cancer.

MATERIALS AND METHODS

We identified 7,274 men from the Cancer of the Prostate Strategic Urological Research Endeavor database with clinically localized prostate cancer, known body mass index and clinicopathological disease characteristics. Patients were classified by body mass index as normal (less than 25 kg/m(2)), overweight (25 to 29.9 kg/m(2)), obese (30 to 34.9 kg/m(2)) and severely obese (35 kg/m(2) or greater). Associations between body mass index and need for secondary treatment, disease specific survival and overall survival were analyzed using univariate and multivariate models.

RESULTS

Patients were classified by body mass index category as normal (28.8%), overweight (50%), obese (16.4%) and very obese (4.8%). Mean followup was 51.3 +/- 38.5 months. During followup there were 1,044 deaths with 220 (21.1%) from prostate cancer. Stratified by body mass index category the groups differed with regard to the need for secondary treatment (p = 0.05) and overall mortality (p <0.01) but there were no significant differences with regard to disease specific survival (p = 0.09). On multivariate analysis age 65 to 74 years (HR 2.4, p = 0.002), age older than 75 years (HR 3.2, p = 0.0001), high risk disease (HR 1.6, p <0.0001), conservative treatment (HR 1.2, p <0.0001) and presence of diabetes (HR 1.6, p <0.0001) were associated with decreased overall survival. Only conservative treatment (HR 1.4, p <0.0001), high risk disease (HR 8.4, p <0.0001) and intermediate risk disease (HR 2.5, p = 0.004) were associated with decreased disease specific survival.

CONCLUSIONS

In a prospective, community based cohort we were unable to establish a relationship between body mass index and prostate cancer disease specific survival or overall survival.

Expression of androgen and estrogen related proteins in normal weight and obese prostate cancer patients

BACKGROUND

Obesity is associated with an aggressive form of prostate cancer and with alterations in androgen and estrogen metabolism. We hypothesized that changes in components of the sex steroid receptor axis may contribute to the clinical aggressiveness of prostate cancer in obese patients.

METHODS

A database was assembled containing clinical and pathological variables from 539 patients treated with radical prostatectomy at a single urban hospital between 1994 and 2002. Tissue microarrays were constructed from representative patients and expression of androgen receptor (AR), PSA, estrogen receptor alpha (ERalpha), estrogen receptor beta (ERbeta), and aromatase was examined.

RESULTS

Higher BMI correlated strongly with black race, the presence of extra-capsular extension, and higher pathologic stage. Expression of AR, PSA, ERbeta and aromatase in cancerous epithelial cells did not differ according to obesity status. However, decreased expression of ERalpha and aromatase was observed in the stromal compartment surrounding non-cancerous acini in obese patients.

CONCLUSION

We confirm the previously reported associations between obesity and aggressive clinical and pathologic features in our single-institution, urban teaching hospital. In comparing obese versus non-obese patients, there was no difference in expression of androgen or estrogen related proteins in cancerous epithelial cells. However, there was a down-regulation of ERalpha and aromatase in the stroma of obese patients. Our data suggest obesity may cause stromal changes in the sex steroid production and signaling pathways which may affect prostate cancer growth via intracrine/paracrine mechanisms.

Body mass index as a prognostic marker for biochemical recurrence in Dutch men treated with radical prostatectomy

OBJECTIVE

To investigate whether body mass index (BMI) is a prognostic factor for biochemical recurrence (BCR) in Dutch men after radical prostatectomy (RP), as although epidemiological studies of obesity in relation to prostate cancer have provided conflicting results, recent studies from the USA suggest that a higher BMI is a risk factor for progression of prostate cancer.

PATIENTS AND METHODS

Of the 1417 patients with prostate cancer who had RP at two University hospitals, 1302 were included in the present study. BMI (kg/m(2)) classes were defined as normal (<25), overweight (25-30) and obese (> or =30). The median follow-up was 59 months and clinical data were obtained retrospectively from charts. BCR was defined as two consecutive prostate-specific antigen (PSA) levels of >0.1 ng/mL.

RESULTS

In all, 600 patients were classified as having normal weight (43.9%), 665 as overweight (48.6%) and 103 as obese (7.5%). Overall, 297 patients developed BCR after RP; the 10-year risk (95% confidence interval) of BCR was 31.9 (26.6-37.2)%, 30.5 (25.8-35.2)% and 23.9 (14.9-32.9)% for patients in the three categories, respectively (P = 0.836). Multivariable proportional hazard regression analyses of BMI and established prognostic factors for BCR did not change these results.

CONCLUSION

BMI appeared to have no prognostic value for BCR in Dutch patients with clinically localized prostate cancer and treated with RP.

Prediagnostic body-mass index, plasma C-peptide concentration, and prostate cancer-specific mortality in men with prostate cancer: a long-term survival analysis

BACKGROUND

Excess body-mass index (BMI) has been associated with adverse outcomes in prostate cancer, and hyperinsulinaemia is a candidate mediator, but prospective data are sparse. We assessed the effect of prediagnostic BMI and plasma C-peptide concentration (reflecting insulin secretion) on prostate cancer-specific mortality after diagnosis.

METHODS

This study involved men diagnosed with prostate cancer during the 24 years of follow-up in the Physicians' Health Study. BMI measurements were available at baseline in 1982 and eight years later in 1990 for 2546 men who developed prostate cancer. Baseline C-peptide concentration was available in 827 men. We used Cox proportional hazards regression models controlling for age, smoking, time between BMI measurement and prostate cancer diagnosis, and competing causes of death to assess the risk of prostate cancer-specific mortality according to BMI and C-peptide concentration.

FINDINGS

Of the 2546 men diagnosed with prostate cancer during the follow-up period, 989 (38.8%) were overweight (BMI 25.0-29.9 kg/m(2)) and 87 (3.4%) were obese (BMI >/=30 kg/m(2)). 281 men (11%) died from prostate cancer during this follow-up period. Compared with men of a healthy weight (BMI <25 kg/m(2)) at baseline, overweight men and obese men had a significantly higher risk of prostate cancer mortality (proportional hazard ratio [HR] 1.47 [95% CI 1.16-1.88] for overweight men and 2.66 [1.62-4.39] for obese men; p(trend)<0.0001). The trend remained significant after controlling for clinical stage and Gleason grade and was stronger for prostate cancer diagnosed during the PSA screening era (1991-2007) compared with during the pre-PSA screening era (1982-1990) or when using BMI measurements obtained in 1990 compared with those obtained in 1982. Of the 827 men with data available for baseline C-peptide concentration, 117 (14%) died from prostate cancer. Men with C-peptide concentrations in the highest quartile (high) versus the lowest quartile (low) had a higher risk of prostate cancer mortality (HR 2.38 [95% CI 1.31-4.30]; p(trend)=0.008). Compared with men with a BMI less than 25 kg/m(2) and low C-peptide concentrations, those with a BMI of 25 kg/m(2) or more and high C-peptide concentrations had a four-times higher risk of mortality (4.12 [1.97-8.61]; p(interaction)=0.001) independent of clinical predictors.

INTERPRETATION

Excess bodyweight and a high plasma concentration of C-peptide both predispose men with a subsequent diagnosis of prostate cancer to an increased likelihood of dying of their disease. Patients with both factors have the worst outcome. Further studies are now needed to confirm these findings.

Impact of obesity on clinicopathologic outcomes after robot-assisted laparoscopic prostatectomy

PURPOSE

To investigate the impact of body mass index (BMI) on pathologic and functional outcomes after robot-assisted laparoscopic prostatectomy (RALP).

PATIENTS AND METHODS

We evaluated 400 consecutive patients who underwent RALP at the Mayo Clinic between 2002 and 2006. Patients were categorized as normal weight (BMI <25 kg/ m(2), n = 94), overweight (BMI 25-29.9 kg/m(2), n = 187), and obese (BMI >or=30 kg/m(2), n = 119). Clinicopathologic features of the groups were compared, and logistical regression analysis was used to assess the associations of BMI with pathologic and functional outcomes after RALP.

RESULTS

Overweight and obese patients were more likely to have pT(3/4) disease (P = 0.0024) and pathologic Gleason 7 to 10 cancers (P < 0.0001). Overall, 9/94 (9.6%) normal-weight patients had a positive surgical margin (SM), compared with 25/187 (13.4%) overweight patients and 21/119 (17.6%) obese men (P = 0.087). On multivariate analysis, however, increasing BMI was not significantly associated with an increased risk of positive SM (odds ratio 1.12, 95% confidence interval 0.72-1.76, P = 0.61). In addition, although obese men had longer operative times (P = 0.049) and greater intraoperative blood loss (P = 0.04), we found no association between BMI and transfusion requirement (P = 0.34), length of hospital stay (P = 0.54), or the rates of early (P = 0.37) or late (P = 0.86) complications. Moreover, in those patients with follow-up available at 1 year after RALP, obesity did not impact the return of continence (P = 0.62) or potency (P = 0.13).

CONCLUSION

BMI was not an independent predictor of positive SM, complications, incontinence, or erectile dysfunction after RALP. These data suggest that RALP may offer equivalent margin rates and functional outcomes for patients across BMI.

Robotic radical prostatectomy in overweight and obese patients: oncological and validated-functional outcomes

OBJECTIVES

To determine the impact of body mass index (BMI) on perioperative functional and oncological outcomes in patients undergoing robotic laparoscopic radical prostatectomy (RLRP) when stratified by BMI.

METHODS

Data were collected prospectively for 945 consecutive patients undergoing RLRP. Patients were evaluated with the UCLA-PCI-SF36v2 validated-quality-of-life questionnaire preoperatively and postoperatively to 24 months. Patients were stratified by BMI as normal weight (BMI < 25 kg/m(2)), overweight (BMI = 25 to < 30 kg/m(2)) and obese (BMI > or = 30 kg/m(2)) for outcomes analysis.

RESULTS

Preoperatively, obese men had a significantly greater percentage of medical comorbidities (P < .01) as well as a baseline erectile dysfunction (lower mean baseline Sexual Health Inventory for Men score [P = .01] and UCLA-PCI-SF36v2 sexual function domain scores [P = .01]). Mean operative time was significantly longer in obese patients when compared with normal and overweight men (234 minutes vs 217 minutes vs 214 minutes; P = .0003). Although overall complication rates were comparable between groups, a greater incidence of case abortion caused by pneumoperitoneal pressure with excessive airway pressures was noted in obese men. Urinary continence and potency outcomes were significantly lower for obese men at both 12 and 24 months (all P < .05).

CONCLUSIONS

In this series, obese men experienced a longer operative time, particularly during the initial robotic experience. As such, surgeons early in their RLRP learning curve should proceed cautiously with surgery in these technically more difficult patients or reserve such cases until the learning curve has been surmounted. These details, including inferior urinary and sexual outcomes, should be discussed with obese patients during preoperative counseling.

Is the body mass index a predictor of adverse outcome in prostate cancer after radical prostatectomy in a mid-European study population?

OBJECTIVES

To evaluate the effect of body mass index (BMI) on the histopathological and clinical outcome in prostate cancer.

PATIENTS AND METHODS

In a prospective urological cancer database, 620 patients with prostate cancer had a radical prostatectomy (RP) as a curative treatment. The patients were categorized into three groups of BMI (kg/m(2)); <or=25.0 (190, 'normal weight'), >25.0-30.0 (343, 'overweight') and >30.0 (87, 'obese'). We evaluated the histopathological features and the clinical follow-up after RP. The median (range) age of the men was 64.4 (41.1-80.1) years and the median follow-up 5.5 (0.1-15.1) years. The preoperative median prostate-specific antigen (PSA) levels for normal, overweight and obese patients were 9.0 (0.3-133.0), 8.9 (0.4-230.0) and 9.2 (0.5-194.0) ng/mL, respectively.

RESULTS

Serum PSA levels were no different among the three groups (P = 0.92). The normal, overweight and obese patients had organ-confined prostate cancer in 53.7%, 57.1% and 58.6%, respectively (P = 0.34) and had lymph node metastases in 7.9%, 7.6% and 4.6% (P = 0.58). Tumour grading was no different for the three groups (P = 0.25). The PSA recurrence-free, prostate cancer-specific and overall survival for the three BMI groups did not differ significantly (each P > 0.05).

CONCLUSION

The BMI cannot be shown to be a predictor of adverse prognosis either for histopathological features or for the clinical outcome, e.g. PSA-free, prostate cancer-specific and overall survival, in a mid-European study population after RP.

The impact of physical activity on all-cause mortality in men and women after a cancer diagnosis

OBJECTIVE

Existing information regarding the impact of physical activity after a cancer diagnosis on all-cause mortality is limited. We examined the association between different types of physical activity (domestic, walking, sports) and mortality in 293 participants (65.5% women) with a cancer registration prior to the baseline assessment.

METHODS

Participants were drawn from the Scottish Health Surveys (1995, 1998, 2003) that were linked to a national database of cancer registrations and deaths. The main outcome was all-cause mortality during a mean follow-up period of 5.9 +/- 3.2 years. Cox proportional hazards models were used to estimate the risk of all-cause mortality by levels of physical activity.

RESULTS

There were 78 deaths during follow-up. The lowest risks for all-cause mortality were seen in sports activity groups [multivariable-adjusted hazard ratio (HR) for any compared with groups of no sports: 0.47, 95% CI 0.23-0.96, p = 0.039] although light and moderate activity such as domestic activity (HR = 1.04, 0.60-1.80) and regular walking (HR = 0.95, 0.57-1.56) did not confer protection.

CONCLUSION

Participation in an average of more than three sessions of vigorous exercise per week for at least 20 min/session was associated with the lowest risks of all-cause mortality following a cancer diagnosis. Vigorous physical activity could therefore be a more important determinant of survival than duration or total volume of exercise in cancer survivors.

Obesity and risk of biochemical failure for patients receiving salvage radiotherapy after prostatectomy

PURPOSE

Obesity has been proposed as an independent risk factor for patients undergoing surgery or radiotherapy (RT) for prostate cancer. Using body mass index (BMI) as a measure of obesity, we tested its role as a risk factor for patients receiving salvage RT after prostatectomy.

METHODS AND MATERIALS

Rates of subsequent biochemical relapse were examined in 90 patients who underwent salvage RT between 1984 and 2004 for biochemical failure after radical prostatectomy. Median follow-up was 3.7 years. The BMI was tested as a continuous and categorical variable (stratified as <25, 25-<30, and >or=30 kg/m(2)). Univariate and multivariate proportional hazards regression analyses were performed for clinical, pathologic, and treatment factors associated with time to relapse after salvage RT.

RESULTS

There were 40 biochemical failures after salvage RT with a median time to failure of 1.2 years. The BMI was not associated with adverse clinical, pathologic, or treatment factors. On multivariate analysis, obesity was independently significant (hazard ratio [HR], 1.2; p = 0.01), along with RT dose (HR, 0.7; p = 0.003) and pre-RT prostate-specific antigen level (HR, 1.2; p = 0.0003).

CONCLUSIONS

This study is weakly suggestive that obesity may be a risk factor for salvage RT patients. Whether this results from greater biologic aggressiveness or technical inadequacies cannot be answered by this study. Given the very high failure rate observed for severely obese patients, we propose that technical difficulties with RT are at play. This hypothesis is supported by the RT literature and could be prospectively investigated. Techniques that optimize targeting, especially in obese patients, perhaps seem warranted at this time.

Obesity and oncological outcome after radical prostatectomy: impact of prostate-specific antigen-based prostate cancer screening: results from the Shared Equal Access Regional Cancer Hospital and Duke Prostate Center databases

OBJECTIVE

To indirectly test the hypothesis that prostate-specific antigen (PSA)-based screening is biased against obese men due to haemodilution of PSA, and thus results in delayed diagnosis and poorer outcome beyond the biological link between obesity and aggressive prostate cancer.

PATIENTS AND METHODS

We sought to examine the association between body mass index (BMI) and the outcome of radical prostatectomy (RP) separately for men with PSA-detected cancers (cT1c) or with abnormal digital rectal examination (DRE) findings (cT2/T3), and stratified by year of treatment, using two large databases. We conducted a retrospective cohort study of 1375 and 2014 men treated by RP between 1988 and 2007 using the Shared Equal Access Regional Cancer Hospital (SEARCH) and Duke Prostate Center (DPC) databases. We evaluated the association between BMI and adverse pathological features and biochemical progression, using logistic regression and Cox proportional hazards models, adjusting for several clinical characteristics, respectively. Data were examined as a whole and as stratified by clinical stage (cT1c vs cT2/T3) and year of surgery (>or=2000 vs <2000).

RESULTS

In both cohorts a higher BMI was associated with high-grade disease (P <or= 0.02) and positive surgical margins (P < 0.001) and these results did not vary by clinical stage. A higher BMI was significantly associated with biochemical progression (P <or= 0.03) in both cohorts. When stratified by clinical stage, obesity was significantly related to progression in both cohorts among men with T1c cancers (P <or= 0.004) but not in men with cT2/T3 cancers (P > 0.3). Among men with T1c disease, the association between BMI and biochemical progression was limited to men treated in 2000 or later (P <or= 0.002) and was not apparent in men treated before 2000 (P > 0.4).

CONCLUSIONS

Obese men with PSA-detected cancers and treated with RP since 2000 were at significantly greater risk of biochemical progression, while obese men treated before 2000 or diagnosed with an abnormal DRE were not at significantly greater risk of progression. These findings support the hypothesis that current PSA-based screening is less effective at finding cancers in obese men, leading to more aggressive tumours at diagnosis. Lowering the PSA threshold for biopsy among obese men might help to improve outcomes among this high-risk group.

Obesity and positive surgical margins by anatomic location after radical prostatectomy: results from the Shared Equal Access Regional Cancer Hospital database

OBJECTIVES

To determine if there is predilection for any specific anatomical location of positive surgical margins (PSMs) after radical prostatectomy (RP) for prostate cancer in obese men, as previous studies found that obesity was associated with an increased risk of PSMs.

PATIENTS AND METHODS

We analysed retrospectively 1434 men treated with RP between 1989 and 2007 within the Shared Equal Access Regional Cancer Hospital database. The association between increased body mass index (BMI) and overall and site-specific PSMs was assessed using multivariate logistic regression.

RESULTS

After adjusting for several preoperative clinical and pathological characteristics, a higher BMI was associated with an increased risk of PSMs both overall and at all specific anatomical locations (all P <or= 0.007). For mildly obese men, this risk was very similar across all anatomical sites (44-78% increased risk relative to men of normal weight). When BMI was coded as a continuous variable, the odds ratio for the risk of overall PSMs or at any specific locations was nearly identical at 1.05-1.06. Among men with a BMI of >or=35 kg/m2, there was more variation, with the highest excess risk of PSMs at the bladder neck and apex.

CONCLUSIONS

Obesity was associated with an increased risk of overall PSMs and at all anatomical locations. Although the excess risk of PSMs was similar across all anatomical locations, there was a suggestion of a higher risk of apical margins among the most obese men, which if validated, further supports the importance of the apical dissection in all men and suggests added difficulty in obese patients.

Impact of body mass index on biochemical recurrence rates after radical prostatectomy: an analysis utilizing propensity score matching

OBJECTIVES

To investigate the significance of body mass index (BMI) as an independent predictor of biochemical recurrence in men treated with surgery for clinically localized adenocarcinoma of the prostate.

METHODS

A total of 1877 obese patients who underwent radical prostatectomy were matched to overweight and normal-weight patients in a 1:1 ratio on the basis of propensity scores. This resulted in an overall study population of 5631 men. Clinicopathologic characteristics and biochemical recurrence outcomes after surgery were compared between the three BMI cohorts.

RESULTS

Normal-weight patients exhibited lower-grade disease compared with overweight and obese patients (P = 0.021). Lower BMI was also significantly associated with lower rates of positive surgical margins (P <0.001) and extraprostatic extension (P <0.001). Body mass index was not associated with lymph node involvement (P = 0.226) or seminal vesicle invasion (P = 0.142). Body mass index, age, biopsy Gleason score, preoperative prostate-specific antigen level, and clinical tumor stage were independent predictors of biochemical recurrence (P <0.001).

CONCLUSIONS

Propensity score-based matched analyses indicate that higher BMI is associated with adverse pathologic findings and is a strong independent predictor of biochemical recurrence after radical prostatectomy. These results support the hypothesis that inherent differences may exist in the biological properties of prostate cancer in obese men compared with normal-weight men. Therefore, BMI is an important criterion to consider during subsequent decision making and counseling of patients with prostate cancer.

A systematic review of physical activity in prostate cancer survivors: outcomes, prevalence, and determinants

INTRODUCTION

We reviewed physical activity (PA) studies in prostate cancer (PC) survivors investigating (a) the effects of PA on health outcomes, (b) the prevalence of PA, and (c) the determinants of PA.

MATERIALS AND METHODS

A systematic search of the literature identified nine studies on the outcomes of PA, six studies on the prevalence of PA, and four studies on the determinants of PA in PC survivors.

RESULTS

Results showed promising effects of PA on muscular fitness, physical functioning, fatigue, and health-related quality of life. The prevalence of PA varied widely from <30% to >70%, depending on the type of measure used. PA in PC survivors was predicted by motivational variables such as intentions, perceived behavioral control, and subjective norms.

CONCLUSION

Although preliminary research is promising, there remains a significant amount of research to be done on the role of PA in PC survivors. Moreover, future research would benefit from larger samples using randomized controlled trial methodology.

Effect of BMI on primary treatment of prostate cancer

OBJECTIVES

Obese patients with prostate cancer have more aggressive tumors and, in some studies, more prostate cancer-specific deaths. This study was designed to assess the relationship between body mass index (BMI) and treatment patterns of prostate cancer patients.

METHODS

We identified 5041 men with clinically localized prostate cancer (T1-3a, N0M0) who received their first treatment between 1995 and 2006. We derived the odds ratios (OR) for the likelihood of receiving each type of therapy compared with radical prostatectomy by BMI categories using multinomial logistic regression. In our analysis we controlled for age at diagnosis, race/ethnicity, education level, clinical risk category, and number of co-morbidities.

RESULTS

A total of 28.1% of patients were classified as normal BMI, 50.5% were overweight, 16.5% were obese, and 4.8% were very obese. The adjusted OR of receiving nonsurgical therapies (brachytherapy, external radiation, primary androgen deprivation, and active surveillance) increased relative to radical prostatectomy for increasing obesity (P = 0.003). Compared with the patients with normal BMI, very obese patients were more likely to receive brachytherapy (OR 1.59, 95% confidence interval [CI] 1.01 to 2.52), external radiation (OR 1.29, 95% CI 0.73 to 2.26), primary androgen therapy only (OR 1.77, 95% CI 1.12 to 2.81), and active surveillance (OR 1.06, 95% CI 0.52 to 2.17) compared with radical prostatectomy.

CONCLUSIONS

In a large cohort of American prostate cancer patients, a significant trend toward nonsurgical treatment modalities was apparent with increasing BMI.

Obesity and prostate cancer mortality

It has long been known that obesity modestly increases the risk of prostate cancer mortality. Only recently, however, have studies examined whether this association is due to an increased risk of aggressive disease and/or worse outcomes following initial diagnosis and treatment. This distinction is important, because if obesity increases the risk of metastasis and death following treatment, weight loss could be an effective adjunct treatment. We now have good evidence that obesity increases the risk of aggressive prostate cancer, but reduces the risk of low-grade, nonaggressive cancer. In addition, several studies have found that obesity increases the risk of biochemical recurrence following prostatectomy; however, the few studies that have examined more definitive end points, metastases and death, have been less consistent. Furthermore, there are no studies that have examined whether weight loss after diagnosis favorably affects prostate cancer outcome. While accepting the current limitations in our knowledge base, it is our opinion that it is appropriate for physicians to counsel their patients to lose weight following prostate cancer diagnosis and motivate this change in behavior by emphasising the likely benefit of improving long-term outcome.

Obesity is not predictive of overall survival following permanent prostate brachytherapy

PURPOSE

To evaluate the impact of obesity on cause-specific (CSS), biochemical progression-free (bPFS), and overall survival (OS) following prostate brachytherapy.

MATERIALS AND METHODS

From April 1995 through March 2003, 1093 consecutive patients underwent brachytherapy for clinical T1b-T3a (2002 AJCC) prostate cancer. The median follow-up was 5.6 years. Evaluated body mass index (BMI) subgroups were < 25 (n = 258), 25.0 to 29.9 (n = 547), 30.0 to 34.9 (n = 214), and > or = 35 (n = 74) kg/m2, respectively. A total of 430 (39.9%) and 589 (53.9%) of the patients received androgen deprivation therapy or supplemental external beam radiation therapy, respectively. Multiple clinical, treatment, and dosimetric parameters were evaluated as predictors of CSS, bPFS, and OS.

RESULTS

The 11-year CSS, bPFS, and OS for the entire cohort were 97.5%, 95.6%, and 77.6%, respectively. BMI did not impact CSS or bPFS for any of the BMI cohorts. However, OS was statistically lower in patients with a BMI < 25 kg/m2 (P = 0.014). A Cox linear regression analysis demonstrated that Gleason score was the best predictor of CSS while percent-positive biopsies, risk group, V100 and hypertension predicted for bPFS. Patient age and tobacco use were the strongest predictors of OS. A total of 128 patients have died with 108 (84.4%) of the deaths the result of cardiovascular/pulmonary disease (73) and second malignancies (35). To date, 12 patients have died of metastatic prostate cancer.

CONCLUSION

Obesity did not impact CSS, bPFS, or OS in patients treated with permanent prostate brachytherapy. Cardiovascular or pulmonary disease and second malignancies substantially outweighed prostate cancer as competing causes of death.

A single-institution comparison between radical perineal and radical retropubic prostatectomy on perioperative and pathological outcomes for obese men: an analysis of the Duke Prostate Center database

OBJECTIVES

To examine the association between body mass index (BMI) and operative time, estimated blood loss (EBL), and adverse pathologic features in patients undergoing either radical perineal prostatectomy (RPP) or radical retropubic prostatectomy (RRP).

METHODS

We performed a retrospective analysis of 1006 patients treated with RPP or RRP at our institution from 1988 to 2005. Operative times and EBL were compared among BMI groups for both RPP and RRP. The odds ratio of positive surgical margins was estimated for the BMI categories using logistic regression after adjusting for preoperative and pathologic characteristics.

RESULTS

Increased BMI was significantly associated with increased operative time and EBL for men treated with either RPP or RRP (all P < or = 0.03), though the associations were weak (all Spearman r < or = 0.19). After adjusting for multiple clinical preoperative characteristics, higher BMI was associated with positive surgical margins among all patients (P trend <0.001). The association between obesity and surgical margins remained after adjusting for pathologic characteristics (P trend = 0.001) with similar patterns among RRP (P trend = 0.03) and RPP (P trend = 0.01) patients.

CONCLUSIONS

For mildly obese men, both RPP and RRP are associated with a similarly increased risk of higher EBL, longer operative time, and positive surgical margins. These data do not provide evidence to suggest that RPP should be preferred over RRP for mildly obese men. Further study is needed among men with a very high BMI.

Association between prostate-specific antigen and leptin, adiponectin, HbA1c or C-peptide among African-American and Caucasian men

Prior studies report slightly lower prostate-specific antigen (PSA) levels among obese men. To understand this effect, we investigated the association between PSA and blood HbA1c, C-peptide, leptin and adiponectin levels in African-American (AA) (n=121) and Caucasian (CA) (n=121) men. Among AA men, PSA levels decreased with increasing C-peptide levels (PSA=0.99, 0.93, 0.75 and 0.53 ng ml(-1) across quartiles of C-peptide, respectively; P(trend)=0.005). Among CA men, PSA levels decreased with increasing HbA1c (PSA=0.84, 0.73, 0.77 and 0.45 ng ml(-1) across quartiles of HbA1c, respectively; P(trend)=0.005). This may suggest that metabolic disturbances related to metabolic syndrome or diabetes affect the ability to detect early-stage prostate cancer.

Association of obesity with tumor characteristics and treatment failure of prostate cancer in African-American and European American men

PURPOSE

The impact of body mass index on tumor characteristics and treatment failure in prostate cancer is not well understood in diverse ethnic groups. We evaluated the effect of body mass index in African-American and European American patients from a radical prostatectomy cohort between 1995 and 2004 with regard to tumor histopathological characteristics and biochemical relapse-free survival.

MATERIALS AND METHODS

A total of 924 patients were studied to evaluate whether obese men (body mass index greater than 30) had different preoperative and postoperative tumor characteristics or biochemical relapse-free survival compared to nonobese men. There were 784 European American and 140 African-American patients analyzed using failure time models, adjusted for age, preoperative prostate specific antigen, tumor stage and race.

RESULTS

Mean and median followup was 42 and 36 months, respectively. African-American men were significantly more obese than European American men. Mean body mass index was 29.0 in African-American and 28.1 in European American men (p = 0.003). African-American men (OR 2.30, 95% CI 1.04-5.1) were more likely to have higher tumor stage on final pathology. Obesity was a risk factor for biochemical failure in African-American men (adjusted hazard ratio 5.49, 95% CI 2.16-13.9) but not in European American men (HR 1.41, 95% CI 0.96-2.08), and this difference was statistically significant (p value for interaction 0.036).

CONCLUSIONS

Obesity is associated with poorer tumor prognostic characteristics and decreased biochemical relapse-free survival, particularly in African-American men. These data suggest that obesity may in part explain the poorer prostate cancer prognosis seen in African-American men compared to other racial and ethnic groups.

Combination of physical activity, nutrition, or other metabolic factors and vaccine response

A number of lifestyle factors that reduce cancer risk in the primary prevention setting may be potential new targets for use in combination with cancer vaccines. This review discusses the modulation of energy balance (physical activity, calorie restriction, and obesity prevention), and the supplementation with natural and synthetic analogs of vitamins A and E, as potential interventions for use in combination with cancer vaccines. Additionally, the pharmacologic manipulation of nutrient metabolism in the tumor microenvironment (e.g., arachidonic acid, arginine, tryptophan, and glucose metabolism) is discussed. This review includes a brief overview of the role of each agent in primary cancer prevention; outlines the effects of these agents on immune function, specifically adaptive and/or anti-tumor immune mechanisms, when known; and discusses the potential use of these interventions in combination with therapeutic cancer vaccines. Modulation of energy balance through exercise and strategies targeting nutrient metabolism in the tumor microenvironment represent the most promising interventions to partner with therapeutic cancer vaccines. Additionally, the use of vitamin E succinate and the retinoid X receptor-directed rexinoids in combination with cancer vaccines offer promise. In summary, a number of energy balance- and nutrition-related interventions are viable candidates for further study in combination with cancer vaccines.

Dietary intervention in the management of prostate cancer

PURPOSE OF REVIEW

This review integrates recent reports related to the dietary management of prostate cancer with the existing body of science in an effort to best inform practicing clinicians.

RECENT FINDINGS

Dietary factors are hypothesized to play a significant role in prostate cancer, and have proven to be important in managing prevalent comorbidities in this patient population (cardiovascular disease, diabetes, and osteoporosis). Data regarding diet and prostate cancer are accumulating and randomized controlled trials are underway which will ultimately yield evidence on which to base recommendations regarding dietary regimens, functional foods, and supplement use. Until that time, most data derive from epidemiologic studies that have limitations in showing cause and effect. During the past year, the greatest and most consistent strides have been made in the area of energy balance, with data consistently showing that overweight and obesity are associated with progressive disease and increased overall mortality.

SUMMARY

To date, the strongest evidence regarding diet and prostate cancer relates to energy balance. Urologists aspiring to best clinical practice should encourage their patients to achieve a healthful body weight through regular exercise and a healthful plant-based diet rich in fruits, vegetables, and whole grains. Advocating functional foods or supplements explicitly for cancer control purposes would currently be premature.

Influence of body mass index on prostate-specific antigen failure after androgen suppression and radiation therapy for localized prostate cancer

BACKGROUND

Increasing body mass index (BMI) is associated with shorter time to prostate-specific antigen (PSA) failure after radical prostatectomy. Whether BMI is associated with time to PSA failure was investigated in men treated with androgen suppression therapy (AST) and radiation therapy (RT) for clinically localized prostate cancer.

METHODS

The observational prospective cohort study consisted of 102 men with clinically localized prostate cancer who received 70 Gy RT with 6 months of AST on a single arm of a randomized trial between December 1995 and April 2001. Height and weight data were available at baseline for 99 (97%) of the men, from which BMI was calculated. Adjusting for age (continuous) and known prognostic factors including PSA level (continuous), Gleason score, and T-category, Cox regression analyses were performed to analyze whether BMI (continuous) was associated with time to PSA failure (PSA >1.0 ng/mL and increasing >0.2 ng/mL on 2 consecutive visits).

RESULTS

Median age and median BMI (interquartile range [IQR]) at baseline was 72 (69.1-74.7) years and 27.4 (24.8-30.7) kg/m,(2) respectively. In addition to an increasing PSA level (P = .006) and Gleason 8-10 cancer (P = .024), after a median follow-up (IQR) of 6.9 (5.6-8.5) years, an increasing BMI was also significantly associated with a shorter time to PSA failure (adjusted hazard ratio [HR]: 1.10; 95% confidence interval [CI]: 1.01-1.19; P = .026) after RT and AST.

CONCLUSIONS

After adjusting for known prognostic factors, baseline BMI is significantly associated with time to PSA failure after RT and AST for men with clinically localized prostate cancer. Further study is warranted to assess the impact of an increasing BMI after AST administration on PSA failure, prostate cancer-specific, and all-cause mortality.

Death in patients with recurrent prostate cancer after radical prostatectomy: prostate-specific antigen doubling time subgroups and their associated contributions to all-cause mortality

PURPOSE

Among patients with biochemical recurrence after radical prostatectomy, we found previously that postoperative prostate-specific antigen doubling time (PSADT) was associated with risk of prostate cancer death. However, given the small number of patients in the highest risk PSADT subgroup, it is unclear which PSADT subgroups contribute the greatest to prostate cancer-specific death and how this influences all-cause mortality.

PATIENTS AND METHODS

This study was a retrospective analysis of 379 patients treated with radical prostatectomy between 1982 and 2000 who had a biochemical recurrence and PSADT data available. Mean and median follow-up after surgery was 11.4 (standard deviation, 5.4) and 11.0 years, respectively (range, 1.6 to 23.0 years).

RESULTS

Shorter PSADT was significantly associated with prostate cancer-specific and all-cause mortality (P < .001). Although patients with a PSADT less than 3 months were at the greatest risk of death, because of the limited number of patients in this group, they accounted for only 13% of prostate cancer deaths at 15 years after biochemical recurrence, whereas patients with an intermediate PSADT (3.0 to 8.9 months) accounted for 58% of all prostate cancer deaths. Among patients with a PSADT less than 15 months, prostate cancer accounted for 90% of all deaths. Only patients in the slowest PSADT subgroup (> or = 15 months) had a greater risk of competing-causes mortality compared with that from prostate cancer.

CONCLUSION

Among a select cohort of young, healthy patients with PSA recurrence after radical prostatectomy and a PSADT less than 15 months, prostate cancer accounted for an estimated 90% of all deaths by 15 years after recurrence. The majority of prostate cancer deaths occurred among patients with an intermediate PSADT (3.0 to 8.9 months).

Obesity is associated with increased risks of prostate cancer metastasis and death after initial cancer diagnosis in middle-aged men

BACKGROUND

Current research is inconclusive regarding the effect of obesity on outcomes after a prostate cancer diagnosis. The objective of this study was to examine associations between obesity and the risks of developing metastasis or prostate cancer-specific mortality in a population-based cohort of men with prostate cancer.

METHODS

Seven hundred fifty-two middle-aged men with prostate cancer who were enrolled in a case-control study and remain under long-term follow-up for disease progression and mortality formed the study cohort. Body mass index (BMI) in the year before diagnosis was obtained at the time of initial interview. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) of prostate cancer metastasis and mortality associated with obesity, controlling for age, race, smoking status, Gleason score, stage at diagnosis, diagnostic prostate-specific antigen level, and primary treatment.

RESULTS

Obesity (BMI >or=30 kg/m(2)) was associated with a significant increase in prostate cancer mortality (HR, 2.64; 95% CI, 1.18-5.92). Among men who were diagnosed with local- or regional-stage disease, obesity also was associated with an increased risk of developing metastasis (HR, 3.61; 95% CI, 1.73-7.51). Associations generally were consistent across strata defined by Gleason score (2-6 or 7 [3 + 4] vs 7 [4 + 3] or 8-10), stage (local vs regional/distant for mortality), and primary treatment (androgen-deprivation therapy use: yes vs no).

CONCLUSIONS

Obesity at the time of diagnosis was associated with increased risks of prostate cancer metastasis and death. The increased risk of prostate cancer death or metastasis associated with obesity largely was independent of key clinical prognostic factors at diagnosis.

Obesity and prostate cancer: epidemiology and clinical implications

OBJECTIVES

Both obesity and prostate cancer (PCa) are epidemic in Western society. Although initial epidemiological data appeared conflicting, recent studies have clarified the association between obesity and PCa. Therefore, we sought to review the epidemiological data linking obesity and PCa with an emphasis on the clinical implications and how to improve outcomes among obese men.

METHODS

A PubMed search using the keywords "prostate cancer" and "obesity" was performed. Relevant articles and references were reviewed for data on the association between obesity and PCa.

RESULTS

Recent data suggest obesity is associated with reduced risk of nonaggressive disease but increased risk of aggressive disease. This observation may be explained in part by an inherent bias in our ability to detect PCa in obese men (lower PSA values and larger sized prostates, making biopsy less accurate for finding an existent cancer), which ultimately leads to increased risk of cancer recurrence after primary therapy and increased PCa mortality. Despite this detection bias potentially contributing to more aggressive cancers, multiple biological links also exist between obesity and PCa including higher estradiol, insulin, free IGF-1, and leptin levels, and lower free testosterone and adiponectin levels, all of which may promote more aggressive cancers.

CONCLUSIONS

The association between obesity and PCa is complex. Emerging data suggest obesity increases the risk of aggressive cancer, while simultaneously decreasing the risk of more indolent disease. This is likely driven by both "biological" and "nonbiological" causes. Simple changes in clinical practice patterns can reduce the impact of nonbiological causes and may help improve PCa outcomes among obese men.

Impact of Obesity on the Utility of Preoperative Prostate-Specific Antigen Velocity to Predict for Relapse After Prostatectomy: A Report from the SEARCH Database

OBJECTIVES

To test the validity of preoperative prostate-specific antigen velocity (PSAV) (the rate of PSA rise before diagnosis) as a predictor for relapse after radical prostatectomy, in the context of patient obesity as measured by body mass index (BMI).

METHODS

The rates of biochemical relapse were examined among 215 patients who underwent radical prostatectomy between 1992 and 2005. Kaplan-Meier relapse rates as a function of preoperative PSAV 2 ng/mL/yr or less versus greater than 2 ng/mL/yr were compared in two groups: nonobese patients (normal to overweight, BMI less than 30 kg/m2) and obese patients (mild to severely obese, BMI 30 kg/m2 or greater).

RESULTS

A preoperative PSAV greater than 2 ng/mL/yr was associated with higher relapse rates after radical prostatectomy compared with a PSAV of 2 ng/mL/yr or less, with 5-year relapse-free survival rates of 60% versus 70%, respectively (P = 0.03). Prostate-specific antigen velocity was independently significant on multivariate analysis, along with biopsy Gleason score, percent positive cores, and BMI. In this study 24% of patients were obese. Prostate-specific antigen velocity greater than 2 ng/mL/yr was associated with higher relapse rates in nonobese patients (P = 0.01) but not in obese patients (P = 0.9). The two BMI groups did not differ with respect to any factors. Obese patients with slowly rising PSA (PSAV 2 ng/mL/yr or less) fared just as poorly as nonobese patients with rapidly rising PSA (PSAV greater than 2 ng/mL/yr). Obesity was independently associated with higher relapse rates.

CONCLUSIONS

Preoperative PSAV greater than 2 ng/mL/yr was associated with a higher risk of relapse after radical prostatectomy, but its clinical usefulness might be limited to nonobese patients. Obesity conferred higher relapse rates, regardless of other prognostic factors including preoperative PSAV.

Inverse correlation between body mass index and clinical outcomes in men with advanced castration–recurrent prostate cancer

BACKGROUND

Obesity has a variety of adverse health outcomes, but to the authors' knowledge, the effect of obesity on outcome in patients with advanced prostate cancer is not known. For this reason, the correlation between an elevated body mass index (BMI) and clinical outcomes in patients with metastatic, castration-recurrent prostate cancer (CRPC) was evaluated.

METHODS

A total of 1226 men with CRPC who were enrolled in 9 prospective clinical trials conducted by the Cancer and Leukemia Group B (CALGB) for the treatment of metastatic disease were considered. Eligible patients had progressive prostate cancer during androgen deprivation therapy (with documented castrate levels of testosterone); an Eastern Cooperative Oncology Group performance status of 0 to 2; and adequate hematologic, renal, and hepatic function. Patients were classified based on BMI as normal (18.5-24.9 kg/m(2)), overweight (25-29.9 kg/m(2)), and mildly to severely obese (> or =30 kg/m(2)).

RESULTS

Approximately 24% of the patients had a normal BMI, 43% were overweight, and 33% were mildly to severely obese. On multivariable analysis, BMI was found to be a statistically significant predictor of overall survival and prostate cancer-specific mortality. Compared with men with normal BMIs, the hazard ratios for death for overweight men and mildly to severely obese men were 0.80 (95% confidence interval [95% CI], 0.68-0.93; P = .001) and 0.80 (95% CI, 0.68-0.94; P = .010), respectively.

CONCLUSIONS

In patients with metastatic CRPC, obesity (as defined by an elevated BMI) appears to have a protective effect against overall mortality and prostate cancer-specific mortality. Alternatively, a higher BMI may reflect different cancer biology (ie, the lack of cachexia-producing substances). Further studies to gain a more comprehensive understanding of the mechanisms behind these clinical observations are needed.

Does Body Mass Index Affect Preoperative Prostate Specific Antigen Velocity or Pathological Outcomes After Radical Prostatectomy?

PURPOSE

Several studies suggest that obesity may be associated with more aggressive prostate cancer. Similarly the rate of serum prostate specific antigen change is associated with adverse tumor features and prostate cancer specific mortality rates after radical prostatectomy and radiation therapy. We examined the associations among obesity, prostate specific antigen velocity and adverse tumor features in men treated with radical prostatectomy.

MATERIALS AND METHODS

A total of 587 men with documented preoperative height and weight measurements underwent radical prostatectomy. Prostate specific antigen velocity and other clinicopathological features were compared among men with a body mass index of less than 25, 25 to 29.9 and 30 or greater.

RESULTS

Although Gleason score and prostate volume were similar among groups, there was a significantly lower proportion with organ confined disease and fewer low volume tumors as body mass index increased. Of patients with a body mass index of 30 or greater 52% had a preoperative prostate specific antigen velocity of more than 2 ng/ml yearly compared to 34% with a body mass index of 25 to 29.9 and 26% with a body mass index of less than 25 (p = 0.04). Although on univariate analysis body mass index was associated with adverse clinical and pathological tumor features, on multivariate analysis with other preoperative variables body mass index did not add significant independent predictive information concerning pathological stage (OR 1.02, 95% CI 0.96-1.08).

CONCLUSIONS

Obesity was significantly associated with several adverse pathological features. However, it did not provide independent predictive information concerning final pathological tumor stage. Nevertheless, obesity was significantly associated with increased preoperative prostate specific antigen velocity. Additional studies are needed to further clarify the links between body mass index, prostate specific antigen velocity and prostate cancer progression, and determine whether weight reduction could lead to improved outcomes.