Postoperative Outcomes and Analgesic Requirements of Single-Port vs Multiport Robotic-Assisted Radical Cystectomy.

Objective: To compare outcomes in patients undergoing robotic-assisted radical cystectomy (RARC) with urinary diversion for bladder cancer with either the single-port (SP) or multiport (MP) robotic platform. Methods: All patients who underwent SP and MP RARC at our institution between January 2018 and January 2023 were retrospectively reviewed. Postoperative analgesia was administered by a departmentwide narcotic stewardship protocol, and inpatient and outpatient narcotic use was tracked. The available preoperative clinical, operative, and postoperative outcomes were analyzed using t-test, chi-square, and Fischer exact statistical measures. Kaplan-Meier analysis with log-rank testing was used to determine the freedom from high-grade (Clavien-Dindo grade ≥3) postoperative complications stratified by SP or MP robotic use. Results: Overall, 96 patients underwent RARC with urinary diversion at our institution, with 49 MP and 47 SP procedures performed. Preoperative clinical parameters including age, body mass index, prior abdominal surgery, and use of neoadjuvant chemotherapy were similar between the two groups. Patients undergoing SP RARC had a shorter operative time (386.0 ± 90.9 minutes vs 453.6 ± 94.8 minutes, p < 0.01) and faster return of bowel function (3.4 ± 1.4 days vs 4.5 ± 2.2 days, p < 0.01). However, both cohorts had similar length of hospitalization, postoperative narcotic use, pathologic staging, and rate of positive surgical margin. Within 3 months postoperatively, both cohorts had a similar high-grade complication, hospital readmission, and cancer recurrence rate. Conclusions: The SP robot allows a safe alternative surgical approach for RARC and offers similar postoperative outcomes compared to the MP robot.

Comparison of Magnetic Resonance Imaging-Based Risk Calculators to Predict Prostate Cancer Risk.

Importance: Magnetic resonance imaging (MRI)-based risk calculators can replace or augment traditional prostate cancer (PCa) risk prediction tools. However, few data are available comparing performance of different MRI-based risk calculators in external cohorts across different countries or screening paradigms. Objective: To externally validate and compare MRI-based PCa risk calculators (Prospective Loyola University Multiparametric MRI [PLUM], UCLA [University of California, Los Angeles]-Cornell, Van Leeuwen, and Rotterdam Prostate Cancer Risk Calculator-MRI [RPCRC-MRI]) in cohorts from Europe and North America. Design, Setting, and Participants: This multi-institutional, external validation diagnostic study of 3 unique cohorts was performed from January 1, 2015, to December 31, 2022. Two cohorts from Europe and North America used MRI before biopsy, while a third cohort used an advanced serum biomarker, the Prostate Health Index (PHI), before MRI or biopsy. Participants included adult men without a PCa diagnosis receiving MRI before prostate biopsy. Interventions: Prostate MRI followed by prostate biopsy. Main Outcomes and Measures: The primary outcome was diagnosis of clinically significant PCa (grade group ≥2). Receiver operating characteristics for area under the curve (AUC) estimates, calibration plots, and decision curve analysis were evaluated. Results: A total of 2181 patients across the 3 cohorts were included, with a median age of 65 (IQR, 58-70) years and a median prostate-specific antigen level of 5.92 (IQR, 4.32-8.94) ng/mL. All models had good diagnostic discrimination in the European cohort, with AUCs of 0.90 for the PLUM (95% CI, 0.86-0.93), UCLA-Cornell (95% CI, 0.86-0.93), Van Leeuwen (95% CI, 0.87-0.93), and RPCRC-MRI (95% CI, 0.86-0.93) models. All models had good discrimination in the North American cohort, with an AUC of 0.85 (95% CI, 0.80-0.89) for PLUM and AUCs of 0.83 for the UCLA-Cornell (95% CI, 0.80-0.88), Van Leeuwen (95% CI, 0.79-0.88), and RPCRC-MRI (95% CI, 0.78-0.87) models, with somewhat better calibration for the RPCRC-MRI and PLUM models. In the PHI cohort, all models were prone to underestimate clinically significant PCa risk, with best calibration and discrimination for the UCLA-Cornell (AUC, 0.83 [95% CI, 0.81-0.85]) model, followed by the PLUM model (AUC, 0.82 [95% CI, 0.80-0.84]). The Van Leeuwen model was poorly calibrated in all 3 cohorts. On decision curve analysis, all models provided similar net benefit in the European cohort, with higher benefit for the PLUM and RPCRC-MRI models at a threshold greater than 22% in the North American cohort. The UCLA-Cornell model demonstrated highest net benefit in the PHI cohort. Conclusions and Relevance: In this external validation study of patients receiving MRI and prostate biopsy, the results support the use of the PLUM or RPCRC-MRI models in MRI-based screening pathways regardless of European or North American setting. However, tools specific to screening pathways incorporating advanced biomarkers as reflex tests are needed due to underprediction.

The association of body mass index with tumor aggression among men undergoing radical prostatectomy.

OBJECTIVES: To evaluate the association of preoperative body mass index (BMI) on adverse pathology in peripheral (PZ) and transition zone (TZ) tumors at time of prostatectomy for localized prostate cancer. METHODS: Clinical and pathologic characteristics were obtained from up to 100 consecutive prostatectomy patients from 10 prostate surgeons. BMI groups included normal (18.5-24.9), overweight (25-29.9) and obese (> 29.9). "Aggressive" pathology was defined as the presence of Grade Group (GG) 3 or higher and/or pT3a or higher. Pathologic characteristics were evaluated for association with BMI using univariate analyses. Our primary outcome was the association of BMI with adverse pathology, which was assessed using logistic regression accounting for patient age. We hypothesized that obese BMI would be associated with aggressive TZ tumor. RESULTS: Among 923 patients, 140 (15%) were classified as "normal" BMI, 413 (45%) were "overweight", and 370 (40%) were "obese." 474 patients (51%) had aggressive PZ tumors while 102 (11%) had aggressive TZ tumors. "Obese" BMI was not associated with aggressive TZ tumor compared to normal weight. Increasing BMI group was associated with overall increased risk of aggressive PZ tumor (HR 1.56 [95CI 1.04-2.34]; P = 0.03). Among patients with GG1 or GG2, increasing BMI was associated with presence of pT3a or higher TZ tumor (P = 0.03). CONCLUSIONS: Increased BMI is associated with adverse pathology in PZ tumors. TZ adverse pathology risk may be increased among obese men with GG1 or GG2 disease, which has implications for future studies assessing behavioral change among men whose tumors are actively monitored.

Surgical Management and Considerations for Patients with Localized High-Risk Prostate Cancer.

OPINION STATEMENT: Localized high-risk (HR) prostate cancer (PCa) is a heterogenous disease state with a wide range of presentations and outcomes. Historically, non-surgical management with radiotherapy and androgen deprivation therapy was the treatment option of choice. However, surgical resection with radical prostatectomy (RP) and pelvic lymph node dissection (PLND) is increasingly utilized as a primary treatment modality for patients with HRPCa. Recent studies have demonstrated that surgery is an equivalent treatment option in select patients with the potential to avoid the side effects from androgen deprivation therapy and radiotherapy combined. Advances in imaging techniques and biomarkers have also improved staging and patient selection for surgical resection. Advances in robotic surgical technology grant surgeons various techniques to perform RP, even in patients with HR disease, which can reduce the morbidity of the procedure without sacrificing oncologic outcomes. Clinical trials are not only being performed to assess the safety and oncologic outcomes of these surgical techniques, but to also evaluate the role of surgical resection as a part of a multimodal treatment plan. Further research is needed to determine the ideal role of surgery to potentially provide a more personalized and tailored treatment plan for patients with localized HR PCa.

Are markers of survival associated with perioperative outcomes for tumor thrombectomy patients?

INTRODUCTION: Despite modern advances in surgical and perioperative technologies, management of renal cell carcinoma (RCC) with tumor thrombus (TT) is a morbid procedure that necessitates careful patient selection. It is not known whether established prognostic models for metastatic RCC are suitable prognostic tools for more immediate perioperative outcomes in patients with RCC with TT. We evaluated if established risk models for cytoreductive nephrectomy, as a potential extension of their purpose-built use, are associated with immediate perioperative outcomes in patients undergoing nephrectomy and tumor thrombectomy. METHODS: Perioperative outcomes of patients who underwent radical nephrectomy and tumor thrombectomy for RCC were compared to presences of established predictors of long-term outcomes from prior risk models individually and as stratified by risk grouping (International Metastatic Renal-Cell Carcinoma Database Consortium [IMDC], Memorial Sloan Kettering Cancer Center [MSKCC], M.D. Anderson Cancer Center [MDACC], and Moffitt Cancer Center [MCC]). Wilcoxon rank-sum test or the Kruskal-Wallis test compared continuous variables and the chi-square test or Fisher's exact test compared categorical variables. RESULTS: Fifty-five patients were analyzed with 17 (30.9%) being cytoreductive. Eighteen (32.7%) patients had a level III or higher TT. Individually, preoperative variables were inconsistently associated with perioperative outcomes. Poorer risk patients per the IMDC model had more major postoperative complications (Clavien-Dindo grade≥3, P = 0.008). For the MSKCC model, poorer risk patients had increased intraoperative estimated blood loss (EBL), longer length of stay (LOS), more major postoperative complications, and more likely to discharge to a rehabilitation facility (P < 0.05). Less favorable risk patients per MDACC model had increased LOS (P = 0.038). Poorer risk patients per the MCC model had increased EBL, LOS, major postoperative complications, and 30-day hospital readmissions (P < 0.05). CONCLUSION: Overall, cytoreductive risks models were heterogeneously associated with perioperative outcomes in patients undergoing nephrectomy and tumor thrombectomy. Of available models, the MCC model is associated with more perioperative outcomes including EBL, LOS, major postoperative complications, and readmissions within 30 days when compared to the IMDC, MSKCC, and MDACC models.

Comparison of Perioperative Outcomes Between Single-Port and Multi-Port Robotic Adrenalectomy.

BACKGROUND: Single-port (SP) robotic surgery has been utilized in several surgical procedures. We aim to describe our institution's approach and perioperative experience with SP robotic adrenalectomy and compare it to the traditional multi-port (MP) approach. METHODS: We retrospectively reviewed all patients who underwent robotic adrenalectomy by a single surgeon between March 2019 and March 2020. Patient demographic, perioperative factors, and pathologic outcomes were recorded and analyzed using t-tests, chi-square, or Fisher's exact tests. RESULTS: Thirty-six patients underwent SP (n = 11) and MP (n = 25) robotic adrenalectomy. Age, body mass index, gender, operative time, major Clavien-Dindo complications, and margin status showed no differences. Patients undergoing SP adrenalectomy had a lower estimated blood loss (18.1 ± 13.0 vs 65.6 ± 95.0 cc, P = .02) and smaller lesion size (2.8 ± 1.3 vs 4.1 ± 1.8 cm, P = .04) compared to those undergoing MP. CONCLUSIONS: SP adrenalectomy appears to be a feasible approach in select adrenal masses. Further studies are needed to establish its safety and cost effectiveness.

A prostate biopsy risk calculator based on MRI: development and comparison of the Prospective Loyola University multiparametric MRI (PLUM) and Prostate Biopsy Collaborative Group (PBCG) risk calculators.

OBJECTIVES: To develop and validate a prostate cancer (PCa) risk calculator (RC) incorporating multiparametric magnetic resonance imaging (mpMRI) and to compare its performance with that of the Prostate Biopsy Collaborative Group (PBCG) RC. PATIENTS AND METHODS: Men without a PCa diagnosis receiving mpMRI before biopsy in the Prospective Loyola University mpMRI (PLUM) Prostate Biopsy Cohort (2015-2020) were included. Data from a separate institution were used for external validation. The primary outcome was diagnosis of no cancer, grade group (GG)1 PCa, and clinically significant (cs)PCa (≥GG2). Binary logistic regression was used to explore standard clinical and mpMRI variables (prostate volume, Prostate Imaging-Reporting Data System [PI-RADS] version 2.0 lesions) with the final PLUM RC, based on a multinomial logistic regression model. Receiver-operating characteristic curve, calibration curves, and decision-curve analysis were evaluated in the training and validation cohorts. RESULTS: A total of 1010 patients were included for development (N = 674 training [47.8% PCa, 30.9% csPCa], N = 336 internal validation) and 371 for external validation. The PLUM RC outperformed the PBCG RC in the training (area under the curve [AUC] 85.9% vs 66.0%; P < 0.001), internal validation (AUC 88.2% vs 67.8%; P < 0.001) and external validation (AUC 83.9% vs 69.4%; P < 0.001) cohorts for csPCa detection. The PBCG RC was prone to overprediction while the PLUM RC was well calibrated. At a threshold probability of 15%, the PLUM RC vs the PBCG RC could avoid 13.8 vs 2.7 biopsies per 100 patients without missing any csPCa. At a cost level of missing 7.5% of csPCa, the PLUM RC could have avoided 41.0% (566/1381) of biopsies compared to 19.1% (264/1381) for the PBCG RC. The PLUM RC compared favourably with the Stanford Prostate Cancer Calculator (SPCC; AUC 84.1% vs 81.1%; P = 0.002) and the MRI-European Randomized Study of Screening for Prostate Cancer (ERSPC) RC (AUC 84.5% vs 82.6%; P = 0.05). CONCLUSIONS: The mpMRI-based PLUM RC significantly outperformed the PBCG RC and compared favourably with other mpMRI-based RCs. A large proportion of biopsies could be avoided using the PLUM RC in shared decision making while maintaining optimal detection of csPCa.

Augmenting prostate magnetic resonance imaging reporting to incorporate diagnostic recommendations based upon clinical risk calculators.

Risk calculators have offered a viable tool for clinicians to stratify patients at risk of prostate cancer (PCa) and to mitigate the low sensitivity and specificity of screening prostate specific antigen (PSA). While initially based on clinical and demographic data, incorporation of multiparametric magnetic resonance imaging (MRI) and the validated prostate imaging reporting and data system suspicion scoring system has standardized and improved risk stratification beyond the use of PSA and patient parameters alone. Biopsy-naïve patients with lower risk profiles for harboring clinically significant PCa are often subjected to uncomfortable, invasive, and potentially unnecessary prostate biopsy procedures. Incorporating risk calculator data into prostate MRI reports can broaden the role of radiologists, improve communication with clinicians primarily managing these patients, and help guide clinical care in directing the screening, detection, and risk stratification of PCa.

Multi-institutional analysis of clinical and imaging risk factors for detecting clinically significant prostate cancer in men with PI-RADS 3 lesions.

BACKGROUND: Most Prostate Imaging-Reporting and Data System (PI-RADS) 3 lesions do not contain clinically significant prostate cancer (CSPCa; grade group ≥2). This study was aimed at identifying clinical and magnetic resonance imaging (MRI)-derived risk fac- tors that predict CSPCa in men with PI-RADS 3 lesions. METHODS: This study analyzed the detection of CSPCa in men who underwent MRI-targeted biopsy for PI-RADS 3 lesions. Multivariable logistic regression models with goodness-of-fit testing were used to identify variables associated with CSPCa. Receiver operating curves and decision curve analyses were used to estimate the clinical utility of a predictive model. RESULTS: Of the 1784 men reviewed, 1537 were included in the training cohort, and 247 were included in the validation cohort. The 309 men with CSPCa (17.3%) were older, had a higher prostate-specific antigen (PSA) density, and had a greater likelihood of an anteriorly located lesion than men without CSPCa (p < .01). Multivariable analysis revealed that PSA density (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.05-1.85; p < .01), age (OR, 1.05; 95% CI, 1.02-1.07; p < .01), and a biopsy-naive status (OR, 1.83; 95% CI, 1.38-2.44) were independently associated with CSPCa. A prior negative biopsy was negatively associated (OR, 0.35; 95% CI, 0.24-0.50; p < .01). The application of the model to the validation cohort resulted in an area under the curve of 0.78. A predicted risk threshold of 12% could have prevented 25% of biopsies while detecting almost 95% of CSPCas with a sensitivity of 94% and a specificity of 34%. CONCLUSIONS: For PI-RADS 3 lesions, an elevated PSA density, older age, and a biopsy-naive status were associated with CSPCa, whereas a prior negative biopsy was negatively associated. A predictive model could prevent PI-RADS 3 biopsies while missing few CSPCas. LAY SUMMARY: Among men with an equivocal lesion (Prostate Imaging-Reporting and Data System 3) on multiparametric magnetic resonance imaging (mpMRI), those who are older, those who have a higher prostate-specific antigen density, and those who have never had a biopsy before are at higher risk for having clinically significant prostate cancer (CSPCa) on subsequent biopsy. However, men with at least one negative biopsy have a lower risk of CSPCa. A new predictive model can greatly reduce the need to biopsy equivocal lesions noted on mpMRI while missing only a few cases of CSPCa.

Pathologic findings and clinical outcomes in patients who required neoadjuvant chemotherapy before orchiectomy for testicular germ cell tumors.

Treatment for testicular germ cell tumors (GCTs) includes orchiectomy followed potentially by adjuvant chemotherapy. Rarely, patients with testicular GCT have significant metastatic disease, requiring neoadjuvant chemotherapy before orchiectomy. We investigated the pathologic findings and clinical outcomes in patients who underwent neoadjuvant chemotherapy before orchiectomy for testicular GCT. We identified 45 patients with a mean age of 34 years (range, 15-66 years). Orchiectomy findings included pure teratoma (n = 23), no residual tumor (n = 13), mixed GCT (n = 5), pure seminoma (n = 2), pure yolk sac tumor (YST) (n = 1), and pure germ cell neoplasia in situ (n = 1). Cancer-specific death occurred in 4 of 45 patients (9%). Seventeen of 45 patients (38%) experienced disease progression after initial chemotherapy. Eleven of 45 patients (24%) underwent salvage chemotherapy. Retroperitoneal lymph nodes were the most common site of metastases followed by lung. Overall, the most common type of tumor found in metastases was YST (12/45, 27%) and teratoma (11/45, 24%). Of the 23 patients with residual pure teratoma in the testis, 9 (39%) had disease recurrence and/or progression and 3 (13%) died. In the metastases of these patients, nonteratoma GCT was found in 17 of 23 patients (74%). Nine of 45 patients (20%) had residual testicular nonteratoma GCT. Of the 9 patients, 6 (67%) had disease recurrence and/or progression and 1 (11%) died. Patients with no residual testicular disease (ypT0) had a lower risk of disease recurrence and/or progression (P = .046) and had no deaths. In patients who have undergone neoadjuvant chemotherapy for testicular GCT, the orchiectomy histology often does not correlate with the histology of metastases. No residual testicular disease indicates a better prognosis in these patients.

Integration of magnetic resonance imaging into prostate cancer nomograms.

The decision whether to undergo prostate biopsy must be carefully weighed. Nomograms have widely been utilized as risk calculators to improve the identification of prostate cancer by weighing several clinical factors. The recent inclusion of multiparametric magnetic resonance imaging (mpMRI) findings into nomograms has drastically improved their nomogram's accuracy at identifying clinically significant prostate cancer. Several novel nomograms have incorporated mpMRI to aid in the decision-making process in proceeding with a prostate biopsy in patients who are biopsy-naïve, have a prior negative biopsy, or are on active surveillance. Furthermore, novel nomograms have incorporated mpMRI to aid in treatment planning of definitive therapy. This literature review highlights how the inclusion of mpMRI into prostate cancer nomograms has improved upon their performance, potentially reduce unnecessary procedures, and enhance the individual risk assessment by improving confidence in clinical decision-making by both patients and their care providers.

Intravascular Ultrasound for the Evaluation and Management of Retroperitoneal, Genitourinary Malignancies.

PURPOSE OF REVIEW: Herein we provide a review of intravascular ultrasound (IVUS) and its ability to assist in the evaluation and surgical management of advanced retroperitoneal, genitourinary tumors. RECENT FINDINGS: Advanced retroperitoneal tumors such as advanced renal cell carcinoma, bulky retroperitoneal lymphadenopathy associated with advanced testicular carcinoma, large adrenal tumors, and retroperitoneal sarcomas can invade, compress, or distort vascular anatomy making surgical resection challenging and high risk. Intravascular ultrasonography is commonly used by vascular and cardiothoracic surgery to provide a real time assessment of vascular invasion, compression, and aberrant anatomy to assist with pre-operative and/or intraoperative decision-making. However, the application of this technology to assist with cancer surgery has been limited. The use of intravascular ultrasound prior to radical, extirpative, retroperitoneal surgery involving large vessels can aid in the planning and execution of such challenging operations.

Systematic versus Targeted Magnetic Resonance Imaging/Ultrasound Fusion Prostate Biopsy among Men with Visible Lesions.

PURPOSE: Multiparametric magnetic resonance imaging (mpMRI)-ultrasound (US) fusion-guided biopsy may improve prostate cancer (PCa) detection and reduce grade misclassification. We compared PCa detection rates on systematic, magnetic resonance imaging-targeted, and combined biopsy with evaluation of important subgroups. MATERIALS AND METHODS: Men with clinical suspicion of harboring PCa from 2 institutions with visible Prostate Imaging-Reporting and Data System (PI-RADSTMv2) lesions receiving mpMRI-US fusion-guided prostate biopsy were included (2015-2020). Detection of PCa was categorized by grade group (GG). Clinically-significant PCa (csPCa) was defined as ≥GG2. Patients were stratified by biopsy setting and PI-RADS. RESULTS: Of 1,236 patients (647 biopsy-naïve) included, 626 (50.6%) harbored PCa and 412 (33.3%) had csPCa on combined biopsy. Detection of csPCa was 27.9% vs 23.3% (+4.6%) and GG1 PCa was 11.3% vs 17.8% (-6.5%) for targeted vs systematic cores. Benefit in csPCa detection was higher in the prior negative than biopsy-naïve setting (+7.8% [p <0.0001] vs +1.7% [p=0.3]) while reduction in GG1 PCa detection remained similar (-5.6% [p=0.0002] vs -7.3% [p=0.0001]). Targeted biopsy showed increased csPCa detection for PI-RADS 5, decrease in GG1 for PI-RADS 3, and both for PI-RADS 4 relative to systematic biopsy. Combined biopsy detected more csPCa (+10.0%) and slightly fewer GG1 PCa (-0.5%) compared to systematic alone. Upgrading to ≥GG2 by targeted biopsy occurred in 9.8% with no cancer and 23.6% with GG1 on systematic biopsy. CONCLUSIONS: Combined biopsy doubled the benefit of targeted biopsy alone in detection of csPCa without increasing GG1 PCa diagnoses relative to systematic biopsy. Utility of targeted biopsy was higher in the prior negative biopsy cohort, but advantages of combined biopsy were maintained regardless of biopsy history.

Single- versus multi-port robotic partial nephrectomy: a comparative analysis of perioperative outcomes and analgesic requirements.

Evidence supporting the safe use of the single-port (SP) robot for partial nephrectomy is scarce. The purpose of this study was to compare perioperative outcomes for patients undergoing robotic assisted SP vs multi-port (MP) partial nephrectomy (PN) in a time-matched cohort. All patients with clinically localized renal masses who underwent robotic PN from January 2019 to March 2020 were evaluated. Patients were stratified according to SP vs MP approach. Postoperative analgesia was administered in accordance with department-wide opioid stewardship protocol and outpatient opioid use was tracked. Total of 78 patients underwent robotic PN with 26 patients in the SP cohort. The majority of renal masses had low-complexity (53, 67.9%) R.E.N.A.L. nephrometry scores, without a significant difference between the two cohorts (p = 0.19). A retroperitoneal approach was performed in 16 (20.5%) patients overall, though more commonly via the SP robotic approach (13 vs 3, p < 0.001). Mean operative time for SP cases was 183.9 ± 63.5 min vs 208.6 ± 65.0 min in the MP cohort (p = 0.12). Rate of conversion to radical nephrectomy was 3.8% vs 9.6% for SP vs MP cases, respectively, (p = 0.37). The majority of patients were discharged on postoperative day one (67.9%) irrespective of operative approach (p = 0.60). There were no differences in inpatient milligram morphine equivalents administered (MME, p = 0.08) or outpatient postoperative MME prescribed (p = 0.21) between the two cohorts. In this retrospective single-institution study, SP robotic approach offers similar short-term perioperative outcomes to MP platforms for minimally invasive, nephron-sparing surgery. Using the SP system was not associated with a reduction in postoperative opioid analgesic requirements.

Stereotactic body radiation therapy with simultaneous integrated boost for prostate cancer: does MRI-targeted biopsy alter the boost field?

INTRODUCTION: We aim to investigate if the addition of MRI-US fusion biopsy (FB) can aid in radiation planning and alter the boost field in cases of stereotactic body radiation therapy (SBRT) for prostate cancer with a simultaneous integrated boost (SIB) to a magnetic resonance imaging (MRI)-defined intraprostatic lesion. MATERIALS AND METHODS: Patients undergoing SBRT with SIB for biopsy-proven prostatic adenocarcinoma and a pre-radiation MRI were retrospectively reviewed. 36.25 Gy in 5 fractions was delivered to entire prostate along with SIB of 40 Gy to an MRI-defined intraprostatic lesion. Demographic, radiation planning details, and post-procedural outcomes were compared between patients undergoing systematic transrectal ultrasound (TRUS) biopsy followed by MRI to those undergoing an MRI followed by a FB prior to radiation planning. RESULTS: Forty-three patients underwent systematic TRUS biopsy followed by MRI and 46 patients underwent FB prior to radiation planning. Patients undergoing systematic TRUS biopsy had a smaller prostate volume when compared to the FB cohort (37.58 ± 13.78 versus 50.28 ± 26.76 cc, p = 0.007). No differences in prostate planning target volume (PTVprostate) and boost volume (PTVboost) were noted, but those undergoing TRUS biopsy prior to MRI had a higher integrated boost volume density (IBVD = PTVboost/total prostate volume) (0.16 ± 0.09 versus 0.13 ± 0.06, p = 0.045). No differences were observed in genitourinary or gastrointestinal toxicity rates. CONCLUSIONS: Compared to systematic TRUS biopsy, implementation of prebiopsy prostate MRI and FB allows for safe and feasible SBRT in patients with significantly larger prostate volumes without increasing SIB cancer-directed treatment volumes, oncologic outcomes, quality of life measures, or treatment-related toxicities.