Abstract LB-337: Synergistic effects of twelve common genetic polymorphisms and smoking habits on absolute risk of bladder cancer

Smoking is the strongest established risk factor for bladder cancer and recent studies have identified multiple common susceptibility loci for this disease. Evaluation of gene-smoking interactions on absolute risk of bladder cancer could be important for understanding both the public health and biological significance of the combined effect of these factors. However, previous studies of gene-environment interactions focused on relative rather than absolute risk measures and thus did not address this important question. The aim of our analyses was to estimate absolute risk of bladder cancer in relation to smoking habits and 12 known susceptibility variants for this disease, and to evaluate if smoking risk differences (RD) vary by levels of a polygenic risk score derived from these variants, using additive tests for interaction. Analyses were based on data from 4,098 cases and 5,995 controls of European background in eight studies participating in the NCI bladder cancer genome-wide association study (GWAS). Absolute risks were estimated based on US incidence and mortality data. The main outcome measures were 30-year cumulative absolute risk of bladder cancer and RDs for males aged 50 years in relation to smoking habits and the polygenic risk score. RDs for ever compared to never smokers were significantly larger (P-additive interaction < 0.05) for subjects carrying risk alleles for seven out of 12 known susceptibility variants. Polymorphisms in two detoxification enzymes, NAT2 and UGT1A6, provided the strongest evidence of additive interactions (P-additive interaction of 0.0002 and 0.0003, respectively), supporting the presence of biological interactions between smoking and these variants. The 30-year risk of bladder cancer in never, former and current smokers was 0.7%, 1.6% and 3.7%, respectively, for subjects in the bottom quartile of the polygenic risk score, compared to 2.0%, 5.1% and 8.0% for subjects in the top quartile. This translates into a significantly larger number of projected cases, which could be avoided by smoking prevention in subjects at higher compared to lower genetic risk (P-additive (2df)=4.6x10-9 for top to bottom quartile of the polygenic risk score). In conclusion, our analyses provide strong evidence for synergistic effects of smoking and known susceptibility loci for bladder cancer on the absolute risk of the disease. This indicates that targeting intense smoking prevention efforts to individuals at elevated genetic risk for bladder cancer could improve the public health impact of such efforts. However, genetic susceptibility for other smoking-related diseases, as well as practical and ethical considerations, would need to be taken into account before any recommendations could be made. (MGC, NR are Co-first authors; N.C. and DTS are Co-last authors)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-337. doi:1538-7445.AM2012-LB-337

Improvements in benign prostatic hyperplasia-specific quality of life with dutasteride, the novel dual 5alpha-reductase inhibitor

OBJECTIVES

To examine the effect of the dual-action 5alpha-reductase inhibitor dutasteride on benign prostatic hyperplasia (BPH)-specific health status, as measured by the BPH Impact Index (BII), and to identify baseline and treatment risk factors for those most bothered by their BPH symptoms at the end of the protocol.

PATIENTS AND METHODS

Data were derived from three randomized, double-blind, placebo-controlled, 2-year studies conducted in 4325 men with lower urinary tract symptoms caused by benign prostatic enlargement. Each study comprised a 1-month single-blind placebo run-in period, followed by randomization to oral dutasteride 0.5 mg once daily or placebo for 2 years. Patients eligible for inclusion were consenting men aged >/= 50 years with moderate to severe symptoms (American Urological Symptom Index, AUA-SI, score >/= 12), a prostate volume of >/= 30 mL, a serum prostate-specific antigen (PSA) level of >/= 1.5 or < 10 ng/mL, and a maximum urinary flow rate (Qmax) of </= 15 mL/s. BII scores were recorded at baseline and each study visit. Clinically and statistically significant changes in BII scores from baseline were investigated for each study visit. Logistical regression analysis was used to assess the significance of baseline prostate volume, symptoms, BII item 3, baseline Qmax, serum dihydrotestosterone, testosterone, PSA, age and weight in predicting the BII score at 2 years.

RESULTS

Dutasteride, but not placebo, resulted in clinically and statistically significant improvements in mean BII score from 6 months. Of patients with a baseline BII score of >/= 5 (greatest symptomatic burden) treatment with dutasteride improved the scores by 2.41, while the scores in placebo-treated patients only improved by 1.64. Dutasteride-treated patients with a baseline BII score of < 5 (least symptom burden) had a clinically significant improvement in health status, while placebo-treated patients deteriorated. Regression analysis showed that men with a combination of a baseline BII item-3 score of 3 (bothered a lot) and a high symptom score (AUA-SI >/= 20) were more likely to be bothered by their symptoms at the end of the study. Men receiving placebo were also more likely to be bothered at the end of the study than were those receiving dutasteride.

CONCLUSIONS

Dutasteride treatment is associated with clinically significant improvements in BII score, reflecting improvements in the quality of life of men with BPH. Taken together with previously reported improvements in prostate volume, lower urinary tract symptoms and urinary flow, and diminution of the risk of acute urinary retention and the need for BPH-related surgery, dutasteride offers demonstrable efficacy in the management of BPH.

Periurethral transurethral microwave thermotherapy for the treatment of benign prostatic hyperplasia: an interim 1-year safety and efficacy analysis using the thermatrx TMx-2000

Transurethral microwave thermotherapy (TUMT) represents an accepted minimally invasive approach to the management of patients with benign prostatic hyperplasia (BPH). The TherMatrx TMx-2000 represents a further evolution in TUMT technique. This device uses periurethral transurethral microwave thermotherapy (P-TUMT) technology to directly target the BPH tissue adjacent to the prostatic urethra by using a catheter without a urethral-cooling surface. This article provides a technical review of the device and describes the results of a randomized, controlled multicenter study of P-TUMT for the treatment of symptomatic BPH. A discussion of the physiologic effects of P-TUMT is presented and compared to conventional TUMT. A comparison of P-TUMT to contemporary TUMT series in relation to efficacy and complications is also described. This study concludes that P-TUMT using the TherMatrx TMx-2000 device represents a minimally invasive, efficacious, and well-tolerated treatment for symptomatic BPH.

Serum prostate specific antigen is a strong predictor of future prostate growth in men with benign prostatic hyperplasia. PROSCAR long-term efficacy and safety study

PURPOSE

We analyze patterns of prostate growth in men diagnosed with benign prostatic hyperplasia (BPH) and treated with placebo during 4 years, and determine which baseline parameters were the strongest predictors of growth.

MATERIALS AND METHODS

A total of 3,040 men were enrolled in the 4-year randomized, placebo controlled Proscar Long-Term Efficacy and Safety study. Of these men a subgroup of 10% underwent pelvic magnetic resonance imaging prostate volume measurement at baseline and yearly thereafter. Absolute and percent volume changes during 4 years were calculated in the 164 placebo treated men in the subgroup. The ability of age, baseline prostate volume and prostate specific antigen (PSA) to predict prostate growth in placebo treated patients was assessed by multiple linear regression analyses, receiver operator characteristics curves, and evaluations of growth stratified by tertiles of baseline serum PSA and decades of life.

RESULTS

In placebo treated patients a steady increase in mean plus or minus standard deviation prostate volume from year to year was noted (2.5+/-6.1, 4.9+/-6.8, 6.4+/-8.5 and 7.2+/-8.8 ml. at years 1, 2, 3 and 4, respectively). Mean volume changes at 4 years ranged from -9 to +30 ml. Mean percent change from baseline ranged from 12.5% to 16.6% for men 50 to 59 years old to those 70 to 79 years old. Baseline serum PSA was a strong predictor of growth with 7.4% to 22.0% change at 4 years from the lowest to highest PSA tertiles. Annualized growth rates from baseline were 0.7 ml. per year for PSA 0.2 to 1.3, 2.1 for PSA 1.4 to 3.2 and 3.3 for PSA 3.3 to 9.9 ng./ml. Multiple linear regression analysis showed that serum PSA was a stronger predictor of prostate growth than age or baseline prostate volume. All but 1 man with baseline serum PSA greater than 2.0 ng./ml. had prostate growth during 4 years, and 32.6% of men with serum PSA less than 2.0 exhibited a decrease in volume.

CONCLUSIONS

Serum PSA is a stronger predictor of growth of the prostate in placebo treated patients than age or baseline prostate volume. Since prostate volume is a risk factor for acute urinary retention and the need for BPH related surgery, the ability of PSA to predict prostate growth may be an important factor when considering individual treatment options for BPH. Such use of PSA represents a shift in paradigm away from focusing solely on symptoms of BPH toward a more comprehensive approach with consideration of predicting and preventing risk factors of BPH related outcomes.

Serum prostate specific antigen is a strong predictor of future prostate growth in men with benign prostatic hyperplasia. PROSCAR long-term efficacy and safety study

PURPOSE

We analyze patterns of prostate growth in men diagnosed with benign prostatic hyperplasia (BPH) and treated with placebo during 4 years, and determine which baseline parameters were the strongest predictors of growth.

MATERIALS AND METHODS

A total of 3,040 men were enrolled in the 4-year randomized, placebo controlled Proscar Long-Term Efficacy and Safety study. Of these men a subgroup of 10% underwent pelvic magnetic resonance imaging prostate volume measurement at baseline and yearly thereafter. Absolute and percent volume changes during 4 years were calculated in the 164 placebo treated men in the subgroup. The ability of age, baseline prostate volume and prostate specific antigen (PSA) to predict prostate growth in placebo treated patients was assessed by multiple linear regression analyses, receiver operator characteristics curves, and evaluations of growth stratified by tertiles of baseline serum PSA and decades of life.

RESULTS

In placebo treated patients a steady increase in mean plus or minus standard deviation prostate volume from year to year was noted (2.5+/-6.1, 4.9+/-6.8, 6.4+/-8.5 and 7.2+/-8.8 ml. at years 1, 2, 3 and 4, respectively). Mean volume changes at 4 years ranged from -9 to +30 ml. Mean percent change from baseline ranged from 12.5% to 16.6% for men 50 to 59 years old to those 70 to 79 years old. Baseline serum PSA was a strong predictor of growth with 7.4% to 22.0% change at 4 years from the lowest to highest PSA tertiles. Annualized growth rates from baseline were 0.7 ml. per year for PSA 0.2 to 1.3, 2.1 for PSA 1.4 to 3.2 and 3.3 for PSA 3.3 to 9.9 ng./ml. Multiple linear regression analysis showed that serum PSA was a stronger predictor of prostate growth than age or baseline prostate volume. All but 1 man with baseline serum PSA greater than 2.0 ng./ml. had prostate growth during 4 years, and 32.6% of men with serum PSA less than 2.0 exhibited a decrease in volume.

CONCLUSIONS

Serum PSA is a stronger predictor of growth of the prostate in placebo treated patients than age or baseline prostate volume. Since prostate volume is a risk factor for acute urinary retention and the need for BPH related surgery, the ability of PSA to predict prostate growth may be an important factor when considering individual treatment options for BPH. Such use of PSA represents a shift in paradigm away from focusing solely on symptoms of BPH toward a more comprehensive approach with consideration of predicting and preventing risk factors of BPH related outcomes.

Long-term results after antegrade collagen injection for stress urinary incontinence following radical retropubic prostatectomy

OBJECTIVE

To evaluate the long-term success of antegrade collagen injection in men with stress urinary incontinence after radical prostatectomy.

METHODS

Between October 1994 and January 1996, 20 patients underwent antegrade collagen injection for stress urinary incontinence caused by radical prostatectomy. Evaluation by pad test, urodynamics, and subjective scores was performed before and after injection.

RESULTS

At a mean follow-up of 28 months, 10% of the patients were cured and 35% were improved. All patients received a single treatment (mean total volume of collagen injected 14.5 mL). In 11 patients without long-term improvement, 2 had undergone irradiation previously and 7 had failed retrograde collagen injections. Two patients with vesical neck contracture were successfully treated. Preoperative incontinence severity and stress leak point pressure did not correlate with failure.

CONCLUSIONS

A 45% cured or improved rate at long-term follow-up is possible in men with stress incontinence after radical prostatectomy using a single antegrade collagen injection. Although antegrade delivery of collagen for stress incontinence minimized short-term, technique-related failures, for a substantial number of patients therapy had failed at long-term follow-up.

The effect of finasteride on the risk of acute urinary retention and the need for surgical treatment among men with benign prostatic hyperplasia. Finasteride Long-Term Efficacy and Safety Study Group

BACKGROUND

Finasteride is known to improve urinary symptoms in men with benign prostatic hyperplasia, but the extent to which the benefit is sustained and whether finasteride reduces the incidence of related events, including the need for surgery and the development of acute urinary retention, is not known.

METHODS

In this double-blind, randomized, placebo-controlled trial, we studied 3040 men with moderate-to-severe urinary symptoms and enlarged prostate glands who were treated daily with 5 mg of finasteride or placebo for four years. Symptom scores (on a scale of 1 to 34), urinary flow rates, and the occurrence of outcome events were assessed every four months in 3016 men. Prostate volume was measured in a subgroup of the men. Complete data on outcomes were available for 2760 men.

RESULTS

During the four-year study period, 152 of the 1503 men in the placebo group (10 percent) and 69 of the 1513 men in the finasteride group (5 percent) underwent surgery for benign prostatic hyperplasia (reduction in risk with finasteride, 55 percent; 95 percent confidence interval, 41 to 65 percent). Acute urinary retention developed in 99 men (7 percent) in the placebo group and 42 men (3 percent) in the finasteride group (reduction in risk with finasteride, 57 percent; 95 percent confidence interval, 40 to 69 percent). Among the men who completed the study, the mean decreases in the symptom score were 3.3 in the finasteride group and 1.3 in the placebo group (P<0.001). Treatment with finasteride also significantly improved urinary flow rates and reduced prostate volume (P<0.001).

CONCLUSIONS

Among men with symptoms of urinary obstruction and prostatic enlargement, treatment with finasteride for four years reduces symptoms and prostate volume, increases the urinary flow rate, and reduces the risk of surgery and acute urinary retention.

Treatment with finasteride following radical prostatectomy for prostate cancer

OBJECTIVES

The objective of this study was to evaluate the effect of finasteride (10 mg/d) or placebo on serum prostate-specific antigen (PSA) and recurrence rates in men with detectable PSA levels after radical prostatectomy.

METHODS

A total of 120 men, 48 to 89 years old, previously treated with radical prostatectomy for prostate cancer within the past 10 years, with serum PSA levels between 0.6 and 10.0 ng/mL, with no evidence of skeletal metastasis on bone scan, and with no previous androgen deprivation therapy, were treated with 10 mg finasteride or placebo in a double-blind fashion for 12 months. After the first year, all patients were treated with finasteride for an additional 12 months. Primary endpoints were serum PSA levels and recurrence rates defined as positive bone scan or positive biopsy.

RESULTS

Patients treated with finasteride had a delayed increase in serum PSA compared with placebo of approximately 9 months in the first year and 14 months by the end of the second year. Patients with baseline PSA levels less then 1.0 ng/mL had no significant increase in serum PSA during the 2 years of treatment. Fewer recurrences were observed in the finasteride group, but these differences were not statistically significant. Finasteride was well tolerated, and side effects were balanced between treatment groups.

CONCLUSIONS

The results of this study indicate that treatment with finasteride delays but does not prevent the rise in serum PSA observed in untreated patients with detectable PSA levels after radical prostatectomy. The reduction in local and distant recurrences in the finasteride group suggests that the effect on PSA reflects a direct effect on tumor growth without affecting the initial response to subsequent hormonal therapy. These data require confirmation by studies that are longer and larger, focused on demonstrating significant differences in progression rates and survival before the use of finasteride can be considered as an option for men with detectable PSA levels after radical prostatectomy.

Multicenter, randomized, double-blind, placebo controlled study to investigate the effect of finasteride (MK-906) on stage D prostate cancer

A total of 28 untreated patients with asymptomatic, stage D prostate cancer was randomized in a double-blinded fashion to receive finasteride (10 mg. per day), a 5 alpha-reductase inhibitor or placebo. Patients were evaluated at 3-week intervals by rectal examination, and serum prostate specific antigen (PSA) and prostatic acid phosphatase (PAP) levels, and at 6-week intervals by bone scan and transrectal ultrasound determinations of prostatic volume. Patients stopped the medication at week 6 at the discretion of the investigator when PSA levels increased from baseline. After 12 weeks all patients were reevaluated. Of the patients 13 received finasteride and 15 received placebo. The 2 groups did not differ statistically with respect to patient age, initial PSA and PAP level, or the extent of metastases on initial bone scan. A statistically significant decrease in the median percentage change from baseline in PSA at weeks 3 and 6 occurred in the finasteride group compared to the placebo group (-22.9% versus -2.9% and -15.1% versus +11.7%, respectively, p less than 0.05). Finasteride had no effect upon PAP, serum testosterone, prostatic volume or appearance of bone scans. A decrease in serum PSA in the finasteride treatment group suggests that finasteride exerts a minor effect in patients with prostate cancer. This effect does not approach that seen with medical or surgical castration yet because of the potency preserving feature and the lack of toxicity finasteride may warrant further study in the treatment of prostate cancer.