The Use of Metformin in Overactive Bladder: A Retrospective Nested Case-control, Population-based Analysis

OBJECTIVE

To determine if metformin use is associated with a lower rate of overactive bladder (OAB) medication use. Metformin facilitates the proliferation and migration of stem cells, which have been shown to improve bladder overactivity in animal models.

METHODS

We conducted a retrospective nested case-control cohort study using population-based health-care administrative databases. Our cohort included patients with diabetes mellitus type 2 (DM2) ≥69years. Cases received a prescription for an OAB medication, matched with up to 4 controls based on age, sex, and DM2 diagnosis date. Exposure was a new prescription for metformin prior to receiving an OAB medication. Adjusted odds ratios were estimated using conditional logistic regression. Sensitivity analysis was done to assess the relationship between cumulative days' supply of metformin and use of OAB medications.

RESULTS

Within our cohort of 2,233,084 patients with DM2, there were 16,549 case subjects who received a prescription for an OAB medication, and 64,171 matched controls. We found a positive association between OAB medication use and metformin use (adjusted odds ratios=1.07, 95% CI=1.03-1.12). Summed days' supply of metformin was also associated with OAB medication use, except when summed metformin days was >2220.

CONCLUSION

Older patients with DM2 exposed to metformin had a slightly higher rate of OAB medication use, until 2220+ days' metformin supply, whereafter no association was found. This suggests no protective role for metformin in the prevention of OAB in this patient population.

Prostate MRI versus PSA screening for prostate cancer detection (the MVP Study): a randomised clinical trial

OBJECTIVES

Our objective was to compare prostate cancer detection rates between patients undergoing serum prostate-specific antigen (PSA) vs magnetic resonance imaging (MRI) for prostate cancer screening.

DESIGN

Phase III open-label randomised controlled trial.

SETTING

Single tertiary cancer centre in Toronto, Canada.

PARTICIPANTS

Men 50 years of age and older with no history of PSA screening for ≥3 years, a negative digital rectal exam and no prior prostate biopsy.

INTERVENTIONS

Patients were recommended to undergo a prostate biopsy if their PSA was ≥2.6 ng/mL (PSA arm) or if they had a PIRADS score of 4 or 5 (MRI arm). Patients underwent an end-of-study PSA in the MRI arm.

PRIMARY AND SECONDARY OUTCOME MEASURES

Adenocarcinoma on prostate biopsy. Prostate biopsy rates and the presence of clinically significant prostate cancer were also compared.

RESULTS

A total of 525 patients were randomised, with 266 in the PSA arm and 248 in the MRI arm. Due to challenges with accrual and study execution during the COVID-19 pandemic, the study was terminated early. In the PSA arm, 48 patients had an abnormal PSA and 28 (58%) agreed to undergo a prostate biopsy. In the MRI arm, 25 patients had a PIRADS score of 4 or 5 and 24 (96%) agreed to undergo a biopsy. The relative risk for MRI to recommend a prostate biopsy was 0.52 (95% CI 0.33 to 0.82, p=0.005), compared with PSA. The cancer detection rate for patients in the PSA arm was 29% (8 of 28) vs 63% (15 of 24, p=0.019) in the MRI arm, with a higher proportion of clinically significant cancer detected in the MRI arm (73% vs 50%). The relative risk for detecting cancer and clinically significant with MRI compared with PSA was 1.89 (95% CI 0.82 to 4.38, p=0.14) and 2.77 (95% CI 0.89 to 8.59, p=0.07), respectively.

CONCLUSIONS

Prostate MRI as a stand-alone screening test reduced the rate of prostate biopsy. The number of clinically significant cancers detected was higher in the MRI arm, but this did not reach statistical significance. Due to early termination, the study was underpowered. More patients were willing to follow recommendations for prostate biopsy based on MRI results.

TRIAL REGISTRATION NUMBER

NCT02799303.

Prevalence and natural history of non-metastatic castrate resistant prostate cancer: A population-based analysis

65

Background: The natural history of non-metastatic castrate resistant prostate cancer (nmCRPC) prior to the introduction of novel anti-androgen agents in a real-world setting is largely unknown. Methods: This was a retrospective population-based cohort study of men with nmCRPC in Ontario, Canada. Patients with a diagnosis of prostate cancer, castrate level of testosterone ( < 1.7nmol/L) and a PSA > 2.0nmol/L with a subsequent rise > 25% from the nadir, and without diagnostic or treatment codes for metastasis were included. Annual prevalence of nmCRPC was calculated. Crude time from nmCRPC to metastasis and death are presented as medians with interquartile range (IQR). Predictors of time from nmCRPC to prostate cancer death were compared using univariable and multivariable Fine and Gray subdistributional hazard models to account for the competing risk of non-prostate cancer death. Results: From January 2007 until March 2018, we identified 2045 patients with nmCRPC. Median age was 79 years (IQR: 72-84). A total of 984 patients (48.1%) received upfront hormonal therapy while 584 (25.8%) received initial radiotherapy (RT) and 478 (23.4%) underwent radical prostatectomy. Median time from primary treatment to nmCRPC was 6 years (IQR: 3-10). PSA at the time of meeting nmCRPC criteria was a median of 3.0 ng/L. Patients were followed for a median 31.1 months (IQR: 19.8-47.9). The overall annual prevalence of nmCRPC ranged from 1,519-1,913 patients, representing 7-12% of men with prostate cancer prescribed androgen deprivation therapy each year. Crude median time from nmCRPC to all-cause death was 37.6 months (IQR: 22.1-55.4). Median time from nmCRPC to metastasis and metastasis to all-cause death was 20.0 and 8.3 months, respectively. On regression analysis, older age, ADT use with primary treatment, higher PSA at the time of meeting nmCRPC criteria, and grade group predicted time from nmCRPC to prostate cancer death. Conclusions: This is the largest analysis of the prevalence and natural history of nmCRPC. The current study can be used as a historical cohort to compare how novel imaging modalities and advancements in systemic therapy for patients with nmCRPC impact prevalence estimates and disease trajectory over time.

Prostate specific antigen dynamics and prostate cancer risk: A population-based study

239

Background: Baseline prostate specific antigen (PSA) is a strong predictor of clinically significant prostate cancer. In a large cohort of patients undergoing opportunistic testing, our objective was to assess the association between first serum PSA in combination with other PSA predictors and risk of prostate cancer. Methods: This was a retrospective, population-based study in Ontario, Canada between 2010-2019. Men 40-75 years of age who underwent incident PSA testing with at least two PSA tests during the study period were included. Among men who underwent PSA testing, the PSA levels of patients who were diagnosed with prostate cancer were compared to patients who were not. Univariable and multivariable logistic regression analysis was used to compare any prostate cancer and clinically significant prostate cancer diagnosis (International Society of Urological Pathology [ISUP] grade group 2-5) between groups. Results: A total of 508,238 patients were included in our cohort (12,444 cases and 495,794 controls). The median follow-up time was 8.2 years (IQR: 7.0-9.1). Patients who were diagnosed with prostate cancer were older (median age 62 [IQR: 56-67] versus 56 years [IQR:50-63], standardized difference [SD]:0.61) and had a higher first PSA than patients who were not (median 4.79 [IQR:3.29-6.96] versus 0.96 ng/mL [IQR:0.58-1.69], SD:1.93). Fewer than 0.1% (248/261,463) of patients with a first PSA less than 1.0 ng/mL were diagnosed with prostate cancer during the study period. Our final multivariable model revealed that a first PSA above 2.0 ng/mL (adjusted odds ratio [OR] 6.64, 95%CI: 6.13-7.20, p < 0.001), a final PSA between 4.0 to 9.9 ng/mL and 10.0 to 20.0 ng/mL (adjusted OR 22.09, 95%CI: 20.58-23.71, p < 0.001 and adjusted OR 47.46, 95%CI: 43.28-52.05, p < 0.001, respectively) and change from first to final PSA per 365 days of 20.0 to 99.9% (adjusted OR 3.40, 95%CI: 3.21-3.60, p < 0.001) and more than 100% (adjusted OR 6.91, 95%CI: 6.29-7.59, p < 0.001) were strongly associated with the diagnosis of prostate cancer. The model performed well when predicting any prostate cancer, clinically significant prostate cancer, and when stratified by age. Conclusions: This study suggests that first PSA in combination with final PSA and rate of change can be used to predict prostate cancer diagnosis. Future studies will be conducted to determine the association with metastatic and lethal prostate cancer.

Surgical management of benign prostatic obstruction: 20-year population-level trends

INTRODUCTION

Benign prostatic obstruction (BPO) due to histological benign prostatic hyperplasia is highly prevalent among older men. Despite widespread use of medical therapy, surgical treatment remains a mainstay in the management of BPO. We sought to characterize trends in the surgical management of BPO in Ontario, Canada.

METHODS

We performed an interrupted time-series analysis using segmented regression among men aged 18 years and older undergoing surgical treatment for BPO between January 1, 1994 and December 31, 2014 in Ontario, Canada. The passage of time was considered the primary exposure. The primary outcome was the proportion of all BPO surgeries performed using each of the following modalities: transurethral resection of the prostate (TURP), endoscopic laser prostatectomy, open/laparoscopic prostatectomy, and others.

RESULTS

We identified 136 459 men who underwent BPO surgery between 1994 and 2014. The annual age-adjusted rate of BPO surgery declined significantly over time (24 to 10 per 10 000 population in 1994 and 2014, respectively). From 1994-2001, there were no significant changes in the distribution of BPO surgical modalities, with TURP the most common throughout (97.2% and 97% in 1994 and 2001, respectively). From 2002-2014, there was a significant decline in the use of TURP (92.1% to 76.9%; p=0.027) with a corresponding increase in the use of endoscopic laser prostatectomy (3.5% to 21.9%; p=0.0008).

CONCLUSIONS

This study demonstrates a shift in the management of BPO, with increasing use of endoscopic laser prostatectomy, beginning in 2002. However, TURP remains the most common treatment modality.

Risk of secondary sarcoma after abdominopelvic cancer treatment: Results from a contemporary cohort

317

Background: Our objective was to explore the risk of sarcoma in a large cohort of patients with localized abdominopelvic cancer treated with radiotherapy (RT) compared to surgery. The risk of other secondary non-sarcoma solid organ tumors was also explored. Methods: This is a population-based retrospective cohort study examining the risk of sarcoma in patients with localized prostate, bladder, colorectal, cervical, uterine, and testis cancer between January 1, 2002-December 31, 2016. Multivariable Cox proportional hazard analysis was used to compare time from primary treatment (radical surgery or RT) to second cancer, adjusting for age, comorbidity, income quintile, and rurality, accounting for death as a competing risk. The standardized incidence rate (SIR) was calculated as the ratio of the observed divided by the age- and sex-stratified expected number of sarcoma cases from the Ontario population. Results: 173,580 patients were included (79,662 underwent surgery and 93,918 underwent RT). Most patients had genitourinary (51.4%) or colorectal cancer (39.9%) and 24.4% received chemotherapy. Overall, 332 sarcomas developed over a median 5.7 years (IQR: 2.2-8.9) and were more common in the RT group (239/93918 [0.3%]) compared to the surgery group (93/79662 [0.1%], p<0.001). RT exposure (unadjusted HR=2.67, 95%CI:2.10-3.40, p<0.001, adjusted HR=2.59, 95%CI:2.03-3.31, p<0.001) and perioperative chemotherapy use (HR=1.31, 95%CI:1.03-1.69, p=0.038) were associated with an increased relative rate of sarcoma. Patients who received RT had an increased risk of sarcoma compared to the general population (SIR=1.46, 95%CI:1.12-1.90, p=0.005). For our secondary outcome, patients who received RT had an increased hazard of developing a second non-sarcoma solid malignancy compared to patients who underwent surgery (HR=1.16, 95%CI:1.10-1.22, p<0.001). Conclusions: This is the largest cohort investigating sarcoma in patients with abdominopelvic cancer. Patients treated with RT have a markedly increased risk of sarcoma compared to the general population. RT was an independent risk factor for sarcoma and non-sarcoma second malignancy.

Perioperative chemotherapy for upper tract urothelial carcinoma: A microsimulation Markov model

508

Background: Upper tract urothelial carcinoma (UTUC) accounts for less than 5% of all urothelial cancers. As a result, this disease is clinically understudied and there are no definitive recommendations regarding use and timing of peri-operative chemotherapy. The objective of this study was to create a decision model comparing three treatment pathways in UTUC: nephroureterectomy (NU) alone, neoadjuvant chemotherapy (NAC), and adjuvant chemotherapy (AC). Methods: A Markov microsimulation model was constructed using TreeAge Pro to compare treatment strategies for patients with newly diagnosed UTUC. Our primary outcome was quality adjusted life expectancy (QALE). Secondary outcomes included rates of adverse chemotherapy events, bladder cancer diagnoses, and crude survival. Markov cycle length was 3 months to mimic the follow up interval used in clinical practice for patients with UTUC. A systematic literature review was used to generate probabilities to populate the model. The base case was a 70-year-old patient with a radiographically localized upper tract tumor. Patients could have evidence of nodal disease, but no distant metastasis. Results: A total of 100,000 microsimulations were generated. NAC was preferred with an estimated QALE of 7.52 years versus 6.80 years with NU alone and 7.20 years with AC. Overall, 39.6% of patients in the AC group with invasive pathology received and were able to complete chemotherapy. A total of 37.5% of patients in the NAC group experienced an adverse chemotherapy event compared to 15.1% of patients in the AC group. Bladder cancer recurrence rates were 64.9%, 66.0%, and 67.1% over the patient’s lifetime in the NU, NAC, and AC groups, respectively. Conclusions: This study provides evidence to support the increased use of NAC in UTUC until robust randomized trials can be completed. While the use of NAC in this population appears favourable, the ultimate choice rests with the clinician and should be based on patient and tumor factors.

Abstract A079: MicroRNA-139 regulates prostate cancer aggressiveness by targeting IGF1R

Background: Dysregulated microRNA (miRNA) expression has been implicated in prostate cancer progression. We previously identified a panel of five miRNAs associated with biochemical recurrence and metastasis following prostatectomy based on NGS-based whole miRNome discovery and qPCR-based validation analysis. In this analysis, we examine the effect of miR-139-5p, one of the downregulated miRNAs identified in the panel, in greater detail.

Methods: Using a cohort of 585 patients treated with radical prostatectomy, we examined the prognostic significance of miR-139 (dichotomized around the median) using the Kaplan Meier method and Cox proportional hazard models. We validated these results using The Cancer Genome Atlas (TCGA) data. We created cell lines that overexpressed miR-139 for functional assays. Finally, we examined pathways through which miR-139 may function using prediction algorithms and confirmed targets by Western blotting and reporter assays.

Results: MiR-139 downregulation was significantly associated with a variety of accepted prognostic factors in prostate cancer, including Gleason score, pathologic stage, margin positivity, and lymph node status. MiR-139 was associated with prognosis: the cumulative incidence of biochemical recurrence and metastasis was significantly lower among patients with high miR-139 expression (p=0.0004 and 0.038, respectively). After adjusting for known prognostic factors, patients with high miR-139 expression had significantly lower risk of recurrence (HR 0.77, 95% 0.58-1.04). Validation in the TCGA dataset showed a significant association between dichotomized miR-139 expression and biochemical recurrence (OR 0.52, 95% CI 0.33-0.82). Overexpression of miR-139 in PC3 and DU145 prostate cancer cells led to a significant reduction in cell proliferation and migration compared to control cells. IGF1R was identified as a potential target of miR-139 based on previous work in colorectal and non-small cell lung cancers. Reduced luciferase reporter activity was observed upon co-transfection of the 3′ UTR of IGF1Rβ with miR-139 mimic compared to co-transfection with control mimic. Furthermore, Western blotting of PC3 cells overexpressing miR-139 revealed reduced IGF1Rβ protein expression, as well as reduced expression of its downstream pathway proteins pAKT and pERK. Cell cycle analysis indicated a significantly increased number of cells arrested in G2/M phase in PC3 cells overexpressing miR-139. This was accompanied by an increase in β-galactosidase stained senescent cells and p21 protein expression.

Conclusions: miR-139 is associated with improved prognosis in patients with localized prostate cancer. This appears to be mediated through an IGF1R pathway leading to increased p21 expression, resulting in prostate cancer cell senescence from G2 arrest.

Citation Format: Yutaka Amemiya, Christopher J. Wallis, Tania Benatar, Elizabeth Kobylecky, Linda Sugar, Christopher Sherman, Robert Nam, Arun K. Seth. MicroRNA-139 regulates prostate cancer aggressiveness by targeting IGF1R [abstract]. In: Proceedings of the AACR Special Conference: Prostate Cancer: Advances in Basic, Translational, and Clinical Research; 2017 Dec 2-5; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(16 Suppl):Abstract nr A079.

A Contemporary Prostate Biopsy Risk Calculator Based on Multiple Heterogeneous Cohorts

BACKGROUND

Prostate cancer prediction tools provide quantitative guidance for doctor-patient decision-making regarding biopsy. The widely used online Prostate Cancer Prevention Trial Risk Calculator (PCPTRC) utilized data from the 1990s based on six-core biopsies and outdated grading systems.

OBJECTIVE

We prospectively gathered data from men undergoing prostate biopsy in multiple diverse North American and European institutions participating in the Prostate Biopsy Collaborative Group (PBCG) in order to build a state-of-the-art risk prediction tool.

DESIGN, SETTING, AND PARTICIPANTS

We obtained data from 15 611 men undergoing 16 369 prostate biopsies during 2006-2017 at eight North American institutions for model-building and three European institutions for validation.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We used multinomial logistic regression to estimate the risks of high-grade prostate cancer (Gleason score ≥7) on biopsy based on clinical characteristics, including age, prostate-specific antigen, digital rectal exam, African ancestry, first-degree family history, and prior negative biopsy. We compared the PBCG model to the PCPTRC using internal cross-validation and external validation on the European cohorts.

RESULTS AND LIMITATIONS

Cross-validation on the North American cohorts (5992 biopsies) yielded the PBCG model area under the receiver operating characteristic curve (AUC) as 75.5% (95% confidence interval: 74.2-76.8), a small improvement over the AUC of 72.3% (70.9-73.7) for the PCPTRC (p<0.0001). However, calibration and clinical net benefit were far superior for the PBCG model. Using a risk threshold of 10%, clinical use of the PBCG model would lead to the equivalent of 25 fewer biopsies per 1000 patients without missing any high-grade cancers. Results were similar on external validation on 10 377 European biopsies.

CONCLUSIONS

The PBCG model should be used in place of the PCPTRC for prediction of prostate biopsy outcome.

PATIENT SUMMARY

A contemporary risk tool for outcomes on prostate biopsy based on the routine clinical risk factors is now available for informed decision-making.

Personal prostate-specific antigen screening and treatment choices for localized prostate cancer among expert physicians

INTRODUCTION

We aimed to determine the personal practices of urologists, radiation oncologists, and medical oncologists regarding prostate cancer screening and treatment using the physician surrogate method, which seeks to identify acceptable healthcare interventions by ascertaining interventions physicians select for themselves.

METHODS

A hierarchical, contingent survey was developed through a consensus involving urologists, medical oncologists, and radiation oncologists. It was piloted at the University of Toronto and then circulated to urologists, radiation oncologists, and medical oncologists through professional medical societies in the U.S., Canada, Central and South America, Australia, and New Zealand. The primary outcome was physicians' personal choices regarding prostate-specific antigen (PSA) screening and the secondary outcome was treatment selection among those diagnosed with prostate cancer.

RESULTS

A total of 869 respondents provided consent and completed the survey. Of these, there were 719 urologists, 89 radiation oncologists, nine medical oncologists, and 53 undisclosed specialists. Most (784 of 869 respondents; 90%) endorsed past or future screening for themselves (among male physicians) or for relatives (among female physicians). Among urologists and radiation oncologists making prostate cancer treatment decisions, there was a significant correlation between physician specialty and the treatment selected (Phi coefficient=0.61; p=0.001).

CONCLUSIONS

Physicians who routinely treat prostate cancer are likely to undertake prostate cancer screening themselves or recommend it for immediate family members. Treatment choice is influenced by the well-recognized specialty bias.

Population-based analysis of treatment toxicity among men with castration-resistant prostate cancer

252

Background: There is little phase 4 data regarding the toxicity and effectiveness of contemporary metastatic castrate-resistant prostate cancer (mCRPC) treatments. We examined hospital admissions and emergency room (ER) visits and survival among patients in the Province of Ontario treated with abiraterone, enzalutamide, docetaxel, or cabazitaxel for mCRPC. Methods: We performed a population-based, retrospective cohort study of 2439 men over the age of 65 treated with abiraterone, enzalutamide, docetaxel, or cabazitaxel for mCRPC from 2003-2015 in Ontario, Canada. Outcomes were toxicity (hospitalizations and ER visits) and overall survival. We used multivariable Cox proportional hazards models with time-varying exposures to calculate hazard ratios (HR). Results: Among 2439 patients, cumulative exposure was greatest for docetaxel (n = 1886 (77.3%); 11,436 person-months), followed by abiraterone (n = 893 (36.6%); 5143 person-months), enzalutamide (n = 52 (2.1%); 351 person-months) and cabazitaxel (n = 18 (0.7%); 61 person-months). Abiraterone exposure was not significantly associated with any-cause (HR 0.88, 95% CI 0.72-1.07) or treatment-related (HR 1.09, 95% CI 0.87-1.37) hospitalizations or ER visits. Enzalutamide was not significantly associated with any-cause (HR 1.20, 95% CI 0.69-2.07) or treatment-related (HR 0.85, 95% CI 0.43-1.68) toxicity. Docetaxel exposure was associated with a significantly increased risk of any-cause (HR 1.29, 95% CI 1.15-1.44) and treatment-related (HR 1.52, 95% CI 1.33-1.74) toxicity. Cabazitaxel exposure was also associated with treatment-related (HR 5.94, 95% CI 1.87-18.92) but not any-cause (HR 2.37, 95% CI 0.59-9.63) toxicity. Patients who began CRPC treatment after the introduction of oral therapies had improved overall survival compared with those treated prior to their introduction (aHR 0.70, 95% CI 0.64-0.77). Conclusions: Among patients with metastatic CRPC, treatment with chemotherapy (docetaxel or cabazitaxel) is associated with an increased risk of hospitalizations and emergency room visits. We failed to show a significantly increased risk for patients treated with oral agents (abiraterone or enzalutamide).

Long-term incidence of venous thromboembolic events following cystectomy: A population-based analysis

288

Background: Cancer and immobility both contribute to the development of venous thromboembolic events (VTE), including pulmonary embolism and deep vein thrombosis. As such, patients undergoing radical cystectomy for bladder cancer are at elevated risk. We sought to assess the long-term incidence of VTE among all patients undergoing radical cystectomy in the province of Ontario. Methods: We conducted a population-based cohort study to examine the incidence of VTE, a composite of pulmonary embolism and deep vein thrombosis, among all patients treated with radical cystectomy for bladder cancer between 2002 and 2014 in Ontario, Canada. We estimated the cumulative incidence of VTE and used Fine and Grey competing risk survival analysis to assess risk factors for VTE while accounting for the risk of any cause mortality. Results: Among 3623 eligible patients, the 10 year cumulative incidence of VTE was 6.68% (Table 1). Among those who experienced VTE, the median time from surgery was 216 days (interquartile range 52-677 days; mean 527 days). However, VTE rates peaked much earlier with a mode of 20 days. Neither preoperative (HR 0.68, 95% CI 0.39-1.18) nor postoperative chemotherapy (HR 1.32, 95% CI 0.95-1.84) were significantly associated with VTE incidence. While patients with a prior history of VTE had increased risk of VTE after cystectomy (HR 5.1, 95% CI 2.2-12.0), age, gender, comorbidity score, rurality, diversion type (continent vs ileal conduit), treatment at an academic institution, or year of treatment were not significantly associated with the risk of VTE. Conclusions: Among patients undergoing cystectomy for bladder cancer, the cumulative incidence of VTE continues to rise long after the date of surgery indicating that previous studies may have underestimated these rates, but the highest rates occur at 20 days after surgery. Chemotherapy does not appear to increase the risk of VTE. [Table: see text]

Complications After Systematic, Random, and Image-guided Prostate Biopsy

CONTEXT

Prostate biopsy (PB) represents the gold standard method to confirm the presence of cancer. In addition to traditional random or systematic approaches, a magnetic resonance imaging (MRI)-guided technique has been introduced recently.

OBJECTIVE

To perform a systematic review of complications after transrectal ultrasound (TRUS)-guided, transperineal, and MRI-guided PB.

EVIDENCE ACQUISITION

We performed a systematic literature search of Web of Science, Embase, and Scopus databases up to October 2015, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Complications and mortality following random, systematic, and image-guided PBs were reviewed. Eighty-five references were included.

EVIDENCE SYNTHESIS

The most frequent complication after PB was minor and self-limiting bleeding (hematuria and hematospermia), regardless of the biopsy approach. Occurrence of rectal bleeding was comparable for traditional TRUS-guided and image-guided PBs. Almost 25% of patients experienced lower urinary tract symptoms, but only a few had urinary retention, with higher rates after a transperineal approach. Temporary erectile dysfunction was not negligible, with a return to baseline after 1-6 mo. The incidence of infective complications is increasing, with higher rates among men with medical comorbidities and older age. Transperineal and in-bore MRI-targeted biopsy may reduce the risk of severe infectious complications. Mortality after PB is uncommon, regardless of biopsy technique.

CONCLUSIONS

Complications after PB are frequent but often self-limiting. The incidence of hospitalization due to severe infections is continuously increasing. The patient's general health status, risk factors, and likelihood of antimicrobial resistance should be carefully appraised before scheduling a PB.

PATIENT SUMMARY

We reviewed the variety and incidence of complications after prostate biopsy. Even if frequent, complications seldom represent a problem for the patient. The most troublesome complications are infections. To minimize this risk, the patient's medical condition should be carefully evaluated before biopsy.

Enumerating pelvic recurrence following radical cystectomy for bladder cancer: A Canadian multi-institutional study

INTRODUCTION

We aimed to enumerate the rate of pelvic recurrence following radical cystectomy at university-affiliated hospitals in Canada.

METHODS

Canadian, university-affiliated hospitals were invited to participate. They were asked to identify the first 10 consecutive patients undergoing radical cystectomy starting January 1, 2005, who had urothelial carcinoma stages pT3/T4 N0-2 M0. The first 10 consecutive cases starting January 1, 2005 who met these criteria were the patients submitted by that institution with information regarding tumour stage, age, number of nodes removed, and last known clinical status in regard to recurrence and patterns of failure.

RESULTS

Of the 111 patients, 80% had pT3 and 20% pT4 disease, with 62% being node-negative, 14% pN1, and 27% pN2; 57% had 10 or more nodes removed. Cumulative incidence of pelvic relapse was 40% among the entire group.

CONCLUSIONS

This review demonstrates a high rate of pelvic tumour recurrence following radical cystectomy for pT3/T4 urothelial cancer.

Quantitative ultrasound spectroscopic imaging for characterization of disease extent in prostate cancer patients

Three-dimensional quantitative ultrasound spectroscopic imaging of prostate was investigated clinically for the noninvasive detection and extent characterization of disease in cancer patients and compared to whole-mount, whole-gland histopathology of radical prostatectomy specimens. Fifteen patients with prostate cancer underwent a volumetric transrectal ultrasound scan before radical prostatectomy. Conventional-frequency (~5MHz) ultrasound images and radiofrequency data were collected from patients. Normalized power spectra were used as the basis of quantitative ultrasound spectroscopy. Specifically, color-coded parametric maps of 0-MHz intercept, midband fit, and spectral slope were computed and used to characterize prostate tissue in ultrasound images. Areas of cancer were identified in whole-mount histopathology specimens, and disease extent was correlated to that estimated from quantitative ultrasound parametric images. Midband fit and 0-MHz intercept parameters were found to be best associated with the presence of disease as located on histopathology whole-mount sections. Obtained results indicated a correlation between disease extent estimated noninvasively based on midband fit parametric images and that identified histopathologically on prostatectomy specimens, with an r(2) value of 0.71 (P<.0001). The 0-MHz intercept parameter demonstrated a lower level of correlation with histopathology. Spectral slope parametric maps offered no discrimination of disease. Multiple regression analysis produced a hybrid disease characterization model (r(2)=0.764, P<.05), implying that the midband fit biomarker had the greatest correlation with the histopathologic extent of disease. This work demonstrates that quantitative ultrasound spectroscopic imaging can be used for detecting prostate cancer and characterizing disease extent noninvasively, with corresponding gross three-dimensional histopathologic correlation.

Utility of 5-alpha-reductase inhibitors in active surveillance for favourable risk prostate cancer

INTRODUCTION

This retrospective review compares prostate-specific antigen (PSA) doubling time (DT) prior to the initiation of a 5-alpha-reductase inhibitor (pre-5-ARI) to after the PSA nadir (post-nadir) has been reached for patients on active surveillance for favourable-risk prostate cancer.

METHODS

Between 1996 and 2010, a total of 100 men with a history of 5-ARI use were captured from our active surveillance database. Twenty-nine patients had a sufficient number of PSA values to determine both pre-5-ARI and post-nadir DTs. PSADT was calculated using the general linear mixed-model method.

RESULTS

The median follow-up was 69.5 months. The median pre-5-ARI PSADT was 55.8 (range: 6-556.8) months, while the post-nadir value was 25.2 (range: 6-231) months (p = 0.0081). Six patients were reclassified after an average of 67.7 (range: 59-95) months, due to progression in PSADT (n = 2) or Gleason score (n = 4). The median pre-5-ARI and post-nadir DTs for this group were 42.3 (range: 32.4-91.1) and 21.1 (range: 6-44.3) months, respectively.

CONCLUSION

5-ARIs significantly decreased PSADT compared to prior to their initiation. This effect may be due to preferential suppression of benign tissue following PSA nadir. The resulting PSADT would then represent a more accurate depiction of the true cancer-related DT. If validated with a larger cohort, 5-ARIs may enhance the utility of PSADT as a biomarker of disease progression in active surveillance.

Systematic review of complications of prostate biopsy

CONTEXT

Prostate biopsy is commonly performed for cancer detection and management. The benefits and risks of prostate biopsy are germane to ongoing debates about prostate cancer screening and treatment.

OBJECTIVE

To perform a systematic review of complications from prostate biopsy.

EVIDENCE ACQUISITION

A literature search was performed using PubMed and Embase, supplemented with additional references. Articles were reviewed for data on the following complications: hematuria, rectal bleeding, hematospermia, infection, pain, lower urinary tract symptoms (LUTS), urinary retention, erectile dysfunction, and mortality.

EVIDENCE SYNTHESIS

After biopsy, hematuria and hematospermia are common but typically mild and self-limiting. Severe rectal bleeding is uncommon. Despite antimicrobial prophylaxis, infectious complications are increasing over time and are the most common reason for hospitalization after biopsy. Pain may occur at several stages of prostate biopsy and can be mitigated by anesthetic agents and anxiety-reduction techniques. Up to 25% of men have transient LUTS after biopsy, and <2% have frank urinary retention, with slightly higher rates reported after transperineal template biopsy. Biopsy-related mortality is rare.

CONCLUSIONS

Preparation for biopsy should include antimicrobial prophylaxis and pain management. Prostate biopsy is frequently associated with minor bleeding and urinary symptoms that usually do not require intervention. Infectious complications can be serious, requiring prompt management and continued work into preventative strategies.

How does stereotactic body radiotherapy compare to standard external beam radiotherapy or low-dose rate brachytherapy for low-risk prostate cancer?

e16070

Background: Stereotactic body radiotherapy (SBRT) is an emerging radiotherapy technique that appears to be efficacious, well tolerated and convenient. However, outcomes for patients treated with SBRT are unknown compared to more conventional radiation options for patients with prostate cancer. The purpose of this study is to evaluate and compare late toxicities and biochemical disease-free survival (bDFS) of low risk prostate cancer patients treated SBRT (35Gy/5 fractions), standard external beam radiotherapy (STND; median 76Gy/38 fractions) or low-dose brachytherapy (LDR; iodine-125, 145Gy) at the Odette Cancer Centre. Methods: Consecutive patients with low risk prostate cancer treated with radiation from 2006-2008 were analyzed. Patients treated with SBRT were part of a phase 2 prospective clinical trial; patients treated with STND or LDR had data abstracted from medical charts retrospectively. Patients treated with neoadjuvant androgen deprivation therapy were excluded from biochemical analyses. Univariate (UVA) and multivariate analyses (MVA) of Cox proportional hazard model were conducted to identify significant covariates predicting bDFS. Results: A total of 357 low-risk prostate cancer patients were identified (84 SBRT, 81 STND and 192 LDR). The median follow-up was 57, 62, and 59 months, respectively. At baseline, 85% of patients were T1c, 15% T2a; 100% had GS 6; median PSA 5.9 ng/ml. There were more patients in the STND and LDR cohort who had T2a disease (6%, 21% and 16%, p= 0.013) and the mean PSA was higher in the STND cohort (6.08, 6.69, and 6.02, p=0.017). Patients who received LDR experienced more late hematuria (0%, 1.23% and 11.98%, p<0.0001); otherwise there were no significant differences in late toxicities observed. There were no significant differences in bDFS (97.4% vs 96.9% vs 97.2% at 60 months, p=0.94). There were no covariates identified predicting bDFS on UVA or MVA, including treatment type. Conclusions: SBRT, STND and LDR show equivalent effectiveness and both external beam techniques showed less hematuria than LDR. However, SBRT and LDR are more convenient and less costly than STND. Further prospective studies of SBRT are ongoing.

Quantifying copy number variations in cell-free DNA for potential clinical utility from a large prostate cancer cohort

5072

Background: Prostate cancer (PrCa) is the most frequent non-dermatological malignancy in the male population. Genomic instability resulting in copy number variation (CNV) is a hallmark of malignant transformation. CNV traces from tumors in cell-free DNA (cfDNA) of prostate cancer patients may be identified through massive parallel sequencing (MPS) of serum DNA. These CNV traces may be biomarkers of cancer with clinical applications for screening and follow-up. Methods: DNA was extracted from serum of 205 PrCa patients (Gleason 2 to10), 207 age matched male controls (HC), 10 men with benign hyperplasia (BPH) and 10 with prostatitis (PiS). DNA was amplified using random primers, tagged with a unique molecular identifier per sample, sequenced on a SOLiD system and aligned to the human genome (Build 37). Hits were counted in sliding 100kbp intervals and normalized. Using a random-resampling procedure, genomic regions showing copy number variations in cfDNA that distinguish PrCa from HC were selected. A model using 20 cfDNA regions was cross-validated and used as cfDNA biomarker. Receiver operator characteristics (ROC) curves were calculated for assessment of diagnostic performance by means of area under the curve (AUC). Results: To assess whether CNVs in cfDNA are indicative of PrCa, the number of regions with significant CNV deviation was counted in a first subset of 82 PrCa. Using only the number of regions as measure resulted in an AUC of 0.81 (0.7 – 0.9, p<0.001). Therefore, all samples were used to select regions (n=80) in random resampling (50/50). These regions were used to define a highly significant 20-regions model using five rounds of 10-fold cross-validation (AUC: 0.85±0.7; p< 10-7). This final model discriminated between PrCa and HC with an AUC of 0.92 (0.87 – 0.95) reaching a calculated accuracy of 83%. Both BPH and PiS could be distinguished from PrCa using the cfDNA CNV biomarker with a predicted accuracy of 90%. Conclusions: MPS revealed that only a limited number of chromosomal regions showing CNVs are necessary to achieve statistical separation between prostate cancer and controls. This technique may prove to be clinically useful for screening and follow up of men with prostate cancer.

Whole-transcriptome analysis reveals established and novel associations with TMPRSS2:ERG fusion in prostate cancer

BACKGROUND/AIM

Shortcomings of current methods of prostate cancer detection call for improved biomarkers. The transmembrane protease, serine 2:ets-related gene (TMPRSS2:ERG) gene fusion leads to the overexpression of ERG, an E-twenty six (ETS) family transcription factor, and is the most prevalent genetic lesion in prostate cancer, but its clinical utility remains unclear.

MATERIALS AND METHODS

Two radical prostatectomy samples were analysed by next-generation whole-transcriptome sequencing. The chosen samples differed in fusion gene status, as previously determined by reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

Next-generation sequencing identified the involvement of novel and previously reported prostate cancer-related transcripts, the WNT signalling pathway, evasion of p53-mediated anti-proliferation and several ETS-regulated pathways in the prostate cancer cases examined. Overexpression of Rho GDP-dissociation inhibitor (RhoGDIB), a gene associated with fusion-positive prostate cancer, was found to elicit spindle-shaped morphology, faster cell migration and increased cell proliferation, phenotypic changes suggestive of cancer progression.

CONCLUSION

The present findings confirm the value of comprehensive sequencing for biomarker development and provide potential avenues of future study.

Patient costs associated with external beam radiotherapy treatment for localized prostate cancer: the benefits of hypofractionated over conventionally fractionated radiotherapy

INTRODUCTION

To estimate the out-of-pocket costs for patients undergoing external beam radiotherapy (EBRT) for prostate cancer and calculate the patient-related savings of being treated with a 5-fraction versus a standard 39-fraction approach.

MATERIALS AND METHODS

Seventy patients accrued to the pHART3 (n = 84) study were analyzed for out-of-pocket patient costs as a result of undergoing treatment. All costs are in Canadian dollars. Using the postal code of the patient's residence, the distance between the hospital and patient home was found using Google Maps. The Canada Revenue Agency automobile allowance rate was then applied to determine the cost per kilometer driven.

RESULTS

The average cost of travel from the hospital and pHART3 patient's residence was $246 per person after five trips. In a standard fractionation regimen, pHART3 patients would have incurred an average cost of $1921 after 39 visits. The patients receiving hypofractionated radiotherapy would have paid an average of $38 in parking while those receiving conventional treatment would have paid $293. The difference in out-of-pocket costs for the patients receiving a standard versus hypofractionated treatment was $1930.

CONCLUSIONS

Medium term prospective data shows that hypofractionated radiotherapy is an effective treatment method for localized prostate cancer. Compared to standard EBRT, hypofractionated radiotherapy requires significantly fewer visits. Due to the long distance patients may have to travel to the cancer center and the expense of parking, the short course treatment saves each patient an average of $1900. A randomized study of standard versus hypofractionated accelerated radiotherapy should be conducted to confirm a favorable efficacy and tolerability profile of the shorter fractionation scheme.

Role of 5-alpha-reductase inhibitors in active surveillance of patients with low-risk prostate cancer

14

Background: Active surveillance (AS) is a recognized management option for low-risk prostate cancer. Many institutions use serial PSA values to determine when to reclassify patients into higher risk categories. The impact of 5-alpha-reductase inhibitors (5-ARIs) in this setting has not been well studied. The purpose of this retrospective review was to compare PSA doubling time prior to the initiation of a 5-ARI (pre-5-ARI) to that after the PSA nadir (post-nadir) has been reached.

Methods: Between 1996 and 2010, a total of 100 patients with a history of 5-ARI use were captured from our AS database. Of these, twenty-nine had a sufficient number of PSA values to determine both pre-5-ARI and post-nadir doubling times. The majority had stage T1c disease (89.7%) and Gleason scores of six or lower (93.1%). The average PSA at presentation was 6.93 µg/L. More patients were prescribed dutasteride (79.3%) than finasteride (20.7%). PSA doubling time was calculated using the general linear mixed-model method. Statistical analysis was performed using the non-parametric sign test.

Results: Median follow-up was 69.5 months (mo). For the twenty-nine patients analyzed, the median pre-5-ARI PSA doubling time was 55.8 mo (6-556.8 mo), while that for the post-nadir values was 25.2 mo (6-231 mo) (p=0.0081). Six patients were ultimately reclassified after an average of 67.7 mo (59-95 mo), due to progression in either PSA doubling time (n=2) or Gleason score (n=4). The median pre-5-ARI and post-nadir doubling times for this group were 48.2 mo (32.4-91.1 mo) and 23.3 mo (6-44.3 mo), respectively. Five of the patients underwent radical prostatectomy, while one underwent radiotherapy with androgen deprivation. Of the six patients, one had biochemical failure after an average post-treatment follow-up of 21.3 mo (0-52 mo).

Conclusions: In AS for low-risk prostate cancer, it was found that 5-ARIs significantly decreased PSA doubling time. This effect may be related to preferential suppression of benign prostatic tissue, thereby providing a more accurate depiction of the true cancer-related doubling time. If validated with a larger cohort, 5-ARIs may enhance the utility of PSA doubling time as a biomarker of disease progression in AS.

Three-dimensional ultrasound-based spectroscopic imaging for the detection of prostate cancer

234

Background: The objective of this translational research was to investigate the use of real-time novel three-dimension, quantitative ultrasound-based spectroscopic imaging of the prostate as a means of cancer detection.

Methods: Fourteen patients with T2-3 prostate cancer underwent a 6–9 MHz trans-rectal ultrasound scan of the prostate prior to radical prostatectomy. Equally spaced axial ultrasound images (0.5 cm separation) corresponding elasticity and spectroscopy data were collected in each patient. Colour-coded spectroscopic parametric maps of 0-Mhz intercept (0-Mhz), mid-band fit (MBF) and slope of line of best fit (slope) were generated indicating where the disease in the prostate gland is hypothetically located. Quantitative data (% volume of cancer over the prostate gland) were compared to whole-mount radical prostatectomy histopathology maps to determine the sensitivity and accuracy in parametrically delineating prostate cancer.

Results: Representative data indicate spectral changes were associated with the presence of co-incident disease as located on correlative histopathology whole mount sections. Of the 14 patients enrolled, 7 have been analyzed and presented here. The mean % difference between 0-MHz and MBF, with H&E, was 14% (SD 38%) and 21% (SD 24%), respectively. Gross areas of disease were readily visualized in ultrasound parametric maps and corresponded to a maximum 10dB decrease in 0-MHz or MBF. Parametric maps generated from the spectral slope offered no discrimination of disease. There were differences in scatterer size estimates and scatter concentration estimates between putative disease areas and the remaining tissue.

Conclusions: Initial results suggest that there is good correlation between spectroscopic maps with disease on whole-mount specimens. This method may ultimately permit ultrasound-guided targeted biopsies to improve detection rates and non-invasive assessment of disease for radiotherapy planning.

Personal digital assistant data capture: the future of quality of life measurement in prostate cancer treatment

PURPOSE

This article examines the potential use of personal digital assistant (PDA) data capture systems for real-time linear monitoring of health-related quality of life (HRQOL) in prostate cancer research and clinical care.

METHODS

We discuss the benefits and potential issues of using PDA data capture in the clinical health care setting. In addition, we describe the development and potential use of a PDA data capture system specific to managing HRQOL in prostate cancer treatment.

CONCLUSION

Follow-up health care clinics require a practical and systematic process of HRQOL data capture and analysis. Traditional paper questionnaire data capture is problematic. Data manipulation required for clinical decision-making is impractical for patient feedback on same-day clinic visits. Furthermore, the process of transforming paper questionnaire data to analysis-quality data can compromise data integrity. In contrast, research findings confirm the acceptability, ease of use, and reliability of PDAs in capturing data across health care settings, including the collection of serial HRQOL data. The main concern for PDA capture systems is the ability to compare respondent's answers between the paper and PDA questionnaire. Other challenges included patients reporting a lack of computer literacy and/or poor eyesight, as well as initial start-up costs. If issues are successfully addressed, the use of a PDA data capture system, such as the PDA HRQOL system at Princess Margaret Hospital's Prostate Centre, allows for valid and economical data collection with the possibility of linear real-time measurement of changes in HRQOL. Accordingly, there appears to be significant potential for PDA data collection of serial HRQOL in prostate cancer clinic settings.

Capsaicin may slow PSA doubling time: case report and literature review

Capsaicin is the main pungent component of chili peppers. This is the first case, to our knowledge, that describes prostate-specific antigen (PSA) stabilization in a patient with prostate cancer, who had biochemical failure after radiation therapy. A 66-year-old male underwent radiotherapy treatment for a T2b, Gleason 7 (3+4) adenocarcinoma of the prostate, with a PSA level of 13.3 ng/mL in April 2001. He had 3-dimensional conformal radiotherapy of 46 Gy in 23 fractions to the prostate and pelvis, and a prostate boost of 30 Gy in 15 fractions. Radiotherapy was completed in May 2001 and PSA nadired in January 2002 (0.57). Due to the continued PSA rise, the patient was started on bicalutamide (50 mg orally, daily) and leuprolide acetate (1 dose of 22.5 mg intramuscularly) in July 2005 when PSA was 38.5 ng/mL. Due to poor tolerance of androgen ablation therapy, the patient discontinued treatment and started taking 2.5 mL of habaneros chili sauce, containing capsaicin, 1 to 2 times a week in April 2006. Prostate-specific antigen doubling time (PSAdt) increased from 4 weeks before capsaicin to 7.3 months by October 2006. From October 2006 until November 2007, the patient remained on capsaicin (2.5 to 15 mL daily) and his PSA was stable (between 11 to 14 ng/mL). By January 2008, his PSA rose to 22.3 and he has maintained a PSAdt between 4 and 5 months, where it presently remains. Due to the patient's continued PSA rise, he was restarted on bicalutamide (12.5 mg daily). Apart from PSA relapse, the patient remains free of signs or symptoms of recurrence.

Got central prostate pathology review? A cross-sectional audit of 2009 versus 2003 outcomes

196

Background: Prostate cancer is the most common non-cutaneous cancer in Canadian men; over 24,000 will be newly diagnosed and 4,300 will die from it in 2010. Estimating an individual's risk of disease spreading across the capsule and probability of recurrence with different treatment modalities is common practice in prostate cancer management and often drive the choice or extent of treatment options. A strong predictor of recurrence and organ confined disease is tumor grade. The literature recognizes differences in grading prostate cancer between genitourinary and non-specialized pathologists; we previously reported a 30% change in risk category (Low, GS 2-6; Int., GS 7; High, GS 8-10). However, this report was based on data from 2003/2004. A repeat audit was necessary given Gleason grading practice changes following the 2005 ISUP Consensus Conference.

Methods: Log books from 2009/10 where our Genitourinary Pathologists (GUP) reviewed prostate needle core biopsies were used to identify cases; a retrospective chart review was completed. The following variables were extracted: 1° Gleason score; 2° Gleason score; number of sites; % Gleason 4/5 pattern (overall); perineural invasion (present/absent); extracapsular extension (present/absent). Descriptive statistics were used to summarize the results.

Results: The charts of 132 patients having a GUP biopsy review were extracted. Seventeen percent (22/132) of cases changed risk category. Of the 47 low risk cases, 23% (11/47) were up-graded in risk category (21% by 1 category; 2% by 2 categories). Of the 46 intermediate risk cases, 15% (7/46) were up-graded and 2% (1/46) were down-graded. Of the 39 high risk cases, only 8% (3/39) were down-graded by 1 risk category. Comparatively, there was a 43% reduction in risk category change between 2003/04 (30%) and 2009/10 (17%).

Conclusions: Despite this reduction, a clinically significant proportion of patients changed pathologic risk category upon GUP review. Thus, it is recommended that prostate cancer pathology be routinely reviewed by a GUP as a best practice to optimize management and quality of care. Strategies are still needed to address disparities in pathologic grading and represent a potential area for further investigation.

No significant financial relationships to disclose.

Three-dimensional ultrasound-based spectroscopic imaging for detection of prostate cancer in men

57

Background: The objective of this translational research was to investigate the use of real-time novel three-dimension, quantitative ultrasound-based spectroscopic imaging of the prostate as a means of cancer detection.

Methods: Ten patients with T2-3 prostate cancer underwent a 6-9 MHz trans-rectal ultrasound scan of the prostate prior to radical prostatectomy. Equally spaced axial ultrasound images (0.5 cm separation) corresponding elasticity and spectroscopy data were collected in each patient. Colour-coded spectroscopic parametric maps of 0-Mhz intercept (0-Mhz), mid-band fit (MBF) and slope of line of best fit (slope) were generated indicating where the disease in the prostate gland is hypothetically located. Quantitative data (% volume of cancer over the prostate gland) were compared to whole-mount radical prostatectomy histopathology maps to determine the sensitivity and accuracy in parametrically delineating prostate cancer.

Results: Representative data indicate spectral changes were associated with the presence of co-incident disease as located on correlative histopathology whole mount sections. Of the 10 patients enrolled, 7 have been analyzed and presented here. The mean % difference between 0-MHz and MBF, with H&E, was 14% (SD 38%) and 21% (SD 24%), respectively. Gross areas of disease were readily visualized in ultrasound parametric maps and corresponded to a maximum 10dB decrease in 0-MHz or MBF. Parametric maps generated from the spectral slope offered no discrimination of disease.

Conclusions: Initial results suggest that there is good correlation between spectroscopic maps with disease on whole-mount specimens. This method may ultimately permit ultrasound-guided targeted biopsies to improve detection rates and non-invasive assessment of disease for radiotherapy planning.

No significant financial relationships to disclose.

A review of radical prostatectomy outcomes in active surveillance patients—The Sunnybrook experience

104

Background: Prostate cancer is the most prevalent non-cutaneous cancer among North American men. Approximately 50% of these are favorable risk cancers; the NCCN guideline recommends active surveillance for these patients. Patients are generally followed by serial PSAs, DREs and/or TRUS-guided biopsies with triggers identified for each test. Consequently, about 30% of these cancers will be reclassified to a higher risk and require definitive treatment. Cases treated with radical prostatectomy (rP) give important insights into the biology of these cancers.

Methods: The ASURE database of active surveillance patients was used to identify cases; a retrospective chart review was completed. The following variables were extracted: primary reason for rP; % biochemical failure; % of patients requiring salvage radiation or hormone therapy; Gleason score (GS), tumor size staging and nodal status in the rP specimen; cause and rate of mortality; proportion of patients treated for PSA-doubling times less then 3 years presenting with a GS greater than 7. Descriptive statistics were used to summarize the results.

Results: Of 566 patients in the ASURE database, the charts of 26 patients having an rP were extracted. The primary cause for an rP was a PSA-doubling times less than 3 years (57% of patients) followed by a biopsy indicating a GS of 4+3 or greater (19%). 7% of patients (2/26) were not reclassified but preferred to be treated with rP. 4 patients had biochemical failure (15%) all 4 had salvage therapy. There was 1 cause-specific death. 85% of rP specimens had GS 7, while the remaining had GS 6. Half of these GS 7 individuals had PSA doubling times of less than 3 years.

Conclusions: Radical prostatectomy appears to be an effective deferred treatment for patients who are reclassified on active surveillance as evidenced by low prostate-cancer mortality, low rates of biochemical failure acceptable use of salvage therapy. Of interest is that the majority patients with PSAdt < 3 y have Gleason 7 disease on specimen.

No significant financial relationships to disclose.

Abstract 4035: MicroRNA-221 levels correlate with aggressive and clinically recurrent prostate cancers

One of the most important challenges in prostate cancer research is to identify biomarkers that are predictive of cancer aggressiveness and future tumor recurrence following radical prostatectomy. Recent studies have shown that altered expression of microRNAs (miRs) is involved in the development of prostate cancer, and among the differentially expressed miRNAs, miR-221 may be critical in metastatic induction/regulation. While the precise role of this miRNA in facilitating malignant progression remains unclear, expression of miR-221 in prostate cancer may correlate with disease state/status and serve as a surrogate biomarker for tumor recurrence and/or aggressiveness. In the present study, we sought to investigate whether miR-221 is differentially regulated in patients with aggressive and non-aggressive tumors relative to control normal prostate cell line RWPE-1 and, more specifically, whether this miRNA can be used as biomarker for disease recurrence. To address this question, we initially chose to assess the relative expression of miR-221 in a series of aggressive (n=69) and non-aggressive (n=45) primary carcinoma tissues derived from clinically resected prostates by quantitative real-time PCR. Aggressive tumors were categorized based on clinicopathological parameters such as Gleason score of 8 or higher, high PSA levels, presence of metastasis, invasion to the seminal vesicles, and recurrence after radical prostatectomy. Relative expression of mature miR-221 in tumors was quantified in comparison to control prostate epithelial cell line, RWPE-1, which was set to be 1x. Levels of miR-221 expression were found to be variable. Among all aggressive and non-aggressive cancer patients, expression of miR-221 transcript levels was differentially expressed relative to control sample. However, when we divided this group of patients on the basis of miR-221 expression levels, 72% of the patients with aggressive tumors had miR-221 less than 5-fold the RWPE-1 levels and only 28% of the patients had miR-221 expression equal to or more than 5-fold RWPE-1 levels. On the other hand, 53% of the patients with non-aggressive tumors had miR-221 less than 5-fold the RWPE-1 levels compared to 47% of the patients with miR-221 equal to or more than 5-fold RWPE-1 levels. Our results show that miR-221 is lower in majority of aggressive prostate cancer and differential expression may have utility as a biomarker for disease recurrence.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4035.