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Purpose: Several definitive treatment options are available for prostate cancer, but geographic access to those options is not uniform. We created maps illustrating provider practice patterns relation to patients and assessed the influence of distance to treatment receipt., Methods and Materials: The patient cohort was created by searching the National Medicare Database for patients diagnosed and treated for prostate cancer from 2011 to 2014. The provider cohort was created by querying the American Medical Association Physician Masterfile to identify physicians who had treated patients with prostatectomy, intensity modulated radiation therapy (IMRT), brachytherapy, stereotactic body radiation therapy (SBRT), or proton therapy. Maps detailing the location of providers were created for each modality. Multivariate multinomial logistic regressions were used to assess the association between patient-provider distance and probability of treatment., Results: Cohorts consisted of 89,902 patients treated by 5518 physicians. Substantial numbers of providers practicing established modalities (IMRT, prostatectomy, and brachytherapy) were noted in major urban centers, whereas provider numbers were reduced in rural areas, most notably for brachytherapy. Ninety percent of prostate cancer patients lived within 35.1, 28.9, and 55.6 miles of a practitioner of prostatectomy, IMRT, and brachytherapy, respectively. Practitioners of emerging modalities (SBRT and proton therapy) were predominantly concentrated in urban locations, with 90% of patients living within 128 miles (SBRT) and 374.5 miles (proton). Greater distance was associated with decreased probability of treatment (IMRT -3.8% per 10 miles; prostatectomy -2.1%; brachytherapy -2%; proton therapy -1.6%; and SBRT -1.1%)., Conclusions: Geographic disparities were noted for analyzed treatment modalities, and these disparities influenced delivery., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Introduction: Radiotherapy is an established treatment option for prostate cancer (PCa), both as primary treatment and secondary treatment after radical prostatectomy (RP). Since 1998, detailed data on radiotherapy delivered to Swedish men with PCa (e.g. treatment modalities, absorbed doses, fractionation) have been collated within PCa data Base Sweden (PCBaSe). This study reports patterns of radical radiotherapy for PCa in Sweden over the past two decades. Materials and methods: All men with non-metastatic PCa (1998-2016) who received external beam radiotherapy (EBRT) or high or low dose-rate brachytherapy (HDR-BT/LDR-BT) were identified in PCBaSe. Analyses included: trends in radiation techniques, fractionation patterns and total doses over time; PCa-specific survival comparing treatment in 2007-2017 with 1998-2006; and regional variation in type of primary radiotherapy. Results: About 20,876 men underwent primary radiotherapy. The main treatment modalities include conventionally fractionated (2.0 Gy/fraction) EBRT (51%), EBRT with HDR-BT boost (27%) and hypofractionated (>2.4 Gy/fraction) EBRT (11%). EBRT with photon or proton boost and HDR-BT and LDR-BT monotherapies were each used minimally. Use of dose-escalated EBRT (>74 Gy) and moderate hypofractionation increased over time, while use of HDR-BT declined. Considerable regional variation in treatment modalities was apparent. Risk of PCa death following primary radiotherapy had declined for intermediate-risk (HR: 0.60; 95%CI 0.47-0.87) and high-risk PCa (HR: 0.72; 95%CI 0.61-0.86). Discussion: Increased use of dose escalation and hypofractionated EBRT has occurred in Sweden over the past two decades, reflecting current evidence and practice guidelines. Disease-specific outcomes have also improved. Data collected in PCBaSe provide an excellent resource for further research into RT use in PCa management.

Objective: To develop prostate cancer-specific physician-hospital networks to define hospital-based units that more accurately group hospitals, providers, and the patients they serve., Methods: Using Surveillance, Epidemiology, and End Results-Medicare, we identified men diagnosed with localized prostate cancer between 2007 and 2011. We created physician-hospital networks by assigning each patient to a physician and each physician to a hospital based on treatment patterns. We assessed content validity by examining characteristics of hospitals anchoring the physician-hospital networks and of the patients associated with these hospitals., Results: We identified 42,963 patients associated with 344 physician-hospital networks. Networks anchored by a teaching hospital (compared to a nonteaching hospital) had higher median numbers of prostate cancer patients (117 [interquartile range {71-189} vs 82 {50-126}]) and treating physicians (7 [4-11] vs 4 [3-6]) (both P <0.001). On average, patients traveled farther to networks anchored by a teaching hospital (49 miles [standard deviation] [207] vs 41 [183]; P <.001). Hospitals known as high-volume centers for robotic prostatectomies, proton-beam therapy, and active surveillance had network rates for these procedures well above the mean. Hospitals known as safety net providers served higher proportions of minorities., Conclusion: We empirically developed prostate-cancer specific physician-hospital networks that exhibit content validity and are relevant from a clinical and policy perspective. They have the potential to become targets for policy interventions focused on improving the delivery of prostate cancer care., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: To help guide individualized treatment, we sought to identify baseline predictive factors that impact long-term erectile function following high-dose image-guided radiotherapy (HD-IGRT)., Methods: Potent men with localized prostate cancer treated with radiotherapy alone were enrolled in an institutional review board-approved prospective cohort study. Men received HD-IGRT as primary treatment of prostate cancer. Patient-reported inventories were used to assess erectile function at baseline, 6 months, 2 years, and 5 years after treatment. Long-term potency rates were compared to validated models, and baseline factors were used to create a novel, internally validated nomogram for predicting long-term function., Results: 1,159 men were treated with HD-IGRT. Among 676 men who were potent at baseline and did not receive hormone therapy, the potency rates at 6 months, 2 years, and 5 years were 81%, 68%, and 61%. Recursive partitioning categorized patients into 3 groups based on two factors: baseline response to EPIC Q57 (ability to have an erection) and pre-existing heart disease. At 5 years, the most favorable group reported "very good" on Q57 and had an 80% potency rate (n = 137; p = 0.83); the intermediate group reported "good" on Q57 and had no baseline cardiac disease with a 62% potency rate (n = 145; p = 0.86); and the remaining poor risk group had a 37% potency rate (n = 117; p = 0.19)., Conclusions: Patient-reported pretreatment sexual function and comorbidities enables stratification and prediction of erectile function. EPIC subset questions with baseline comorbidities may potentially serve as a quick and practical clinical tool for predicting sexual survivorship., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Purpose: To evaluate usage trends and identify factors associated with proton beam therapy (PBT) compared to alternative forms of external beam radiation therapy (RT) (EBRT) for localized prostate cancer., Patients and Methods: The National Cancer Database was queried for men with localized (N0, M0) prostate cancer diagnosed between 2004 and 2013, treated with EBRT, with available data on EBRT modality (photon vs. PBT). Binary multiple logistic regression identified variables associated with EBRT modality., Results: In total, 143,702 patients were evaluated with relatively few men receiving PBT (5,709 [4.0%]). Significant differences in patient and clinical characteristics were identified between those men treated with PBT compared to those treated with photon (odds ratio [OR]; 95% CI). Patients treated with PBT were generally younger (OR = 0.73; CI: 0.67-0.82), National Comprehensive Cancer Network low-risk compared to intermediate (0.71; 0.65-0.78) or high (0.44; 0.38-0.5) risk, white vs. black race (0.66; 0.58-0.77), with less comorbidity (Charlson-Deyo 0 vs. 2+; 0.70; 0.50-0.98), live in higher income counties (1.55; 1.36-1.78), and live in metropolitan areas compared to urban (0.21; 0.18-0.23) or rural (0.14; 0.10-0.19) areas. Most patients treated with PBT travelled more than 100 miles to the treatment facility. Annual PBT utilization significantly increased in both total number and percentage of EBRT over time (2.7%-5.6%; P<0.001). PBT utilization increased mostly in men classified as National Comprehensive Cancer Network low-risk (4%-10.2%)., Conclusion: PBT for men with localized prostate cancer significantly increased in the United States from 2004 to 2013. Significant demographic and prognostic differences between those men treated with photons and protons were identified., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: In the current study, the authors sought to both characterize the national trends in proton therapy use for prostate cancer and determine the factors associated with receipt of this limited resource, using what to the best of their knowledge is the largest nationwide cancer registry., Methods: The National Cancer Data Base was used to identify 187,730 patients diagnosed with nonmetastatic prostate cancer from 2004 through 2012 who received external beam radiotherapy as their initial form of definitive therapy. Multivariable logistic regression analysis adjusted for sociodemographic and clinical factors was used to identify independent determinants of proton therapy use., Results: The rate of proton therapy use increased significantly from 2.3% in 2004 to 5.2% in 2011 and 4.8% in 2012 (P value for trend <.0001). Proton therapy for prostate cancer was much more likely to be delivered at an academic compared with nonacademic center and to patients who were white, younger, healthier, from metropolitan areas, from zip codes with higher median household incomes, and who did not have an advanced stage of or high-grade disease (all P<.0001). Compared with white patients, those who were black and Hispanic were found to be significantly less likely to receive proton therapy even after robust multivariable adjustments (adjusted odds ratio, 0.20 [95% confidence interval, 0.18-0.22; P<.0001] and adjusted odds ratio, 0.57 [95% confidence interval, 0.48-0.66; P<.0001], respectively)., Conclusions: The use of proton therapy to treat patients with prostate cancer more than doubled from 2004 to 2012, with striking racial disparities in its use noted despite robust multivariable adjustments. Long-term follow-up is needed to determine whether the increased use of proton therapy for prostate cancer is justified, and ongoing efforts should be made to ensure equal access to resource-limited oncologic therapies. Cancer 2016;122:1505-12. © 2016 American Cancer Society., (© 2016 American Cancer Society.)

This study explores the potential of cone-beam computed tomography (CBCT) for monitoring relative beam range variations due to daily changes in patient anatomy for prostate treatment by anterior proton beams. CBCT was used to image an anthropomorphic pelvic phantom, in eight sessions on eight different days. In each session, the phantom was scanned twice, first at a standard position as determined by the room lasers, and then after it was shifted by 10 mm translation randomly along one of the X, Y, or Z directions. The filling of the phantom bladder with water was not refreshed from day to day, inducing gradual change of the water-equivalent path length (WEPL) across the bladder. MIMvista (MIM) software was used to perform image registration and re-alignment of all the scans with the scan from the first session. The XiO treatment planning system was used to perform data analysis. It was found that, although the Hounsfield unit numbers in CBCT have substantially larger fluctuations than those in diagnostic CT, CBCT datasets taken for daily patient positioning could potentially be used to monitor changes in patient anatomy. The reproducibility of the WEPL, computed using CBCT along anterior-posterior (AP) paths across and around the phantom prostate, over a volume of 360 cc, is sufficient for detecting daily WEPL variations that are equal to or larger than 3 mm. This result also applies to CBCT scans of the phantom after it is randomly shifted from the treatment position by 10 mm. limiting the interest to WEPL variation over a specific path within the same CBCT slice, one can detect WEPL variation smaller than 1 mm. That is the case when using CBCT for tracking daily change of the WEPL across the phantom bladder that was induced by spontaneous change in the bladder filling due to evaporation. In summary, the phantom study suggests that CBCT can be used for monitoring day to day WEPL variations in a patient. The method can detect WEPL variation equal to or greater than 3 mm. The study calls for further investigation using the CBCT data from real patients. If confirmed with real patients' data, CBCT could become, in addition to patient setup, a standard tool for proton therapy pretreatment beam range check.

Purpose: To evaluate a method for quantifying the effect of setup errors and range uncertainties on dose distribution and dose-volume histogram using statistical parameters; and to assess existing planning practice in selected treatment sites under setup and range uncertainties., Methods and Materials: Twenty passively scattered proton lung cancer plans, 10 prostate, and 1 brain cancer scanning-beam proton plan(s) were analyzed. To account for the dose under uncertainties, we performed a comprehensive simulation in which the dose was recalculated 600 times per given plan under the influence of random and systematic setup errors and proton range errors. On the basis of simulation results, we determined the probability of dose variations and calculated the expected values and standard deviations of dose-volume histograms. The uncertainties in dose were spatially visualized on the planning CT as a probability map of failure to target coverage or overdose of critical structures., Results: The expected value of target coverage under the uncertainties was consistently lower than that of the nominal value determined from the clinical target volume coverage without setup error or range uncertainty, with a mean difference of -1.1% (-0.9% for breath-hold), -0.3%, and -2.2% for lung, prostate, and a brain cases, respectively. The organs with most sensitive dose under uncertainties were esophagus and spinal cord for lung, rectum for prostate, and brain stem for brain cancer., Conclusions: A clinically feasible robustness plan analysis tool based on direct dose calculation and statistical simulation has been developed. Both the expectation value and standard deviation are useful to evaluate the impact of uncertainties. The existing proton beam planning method used in this institution seems to be adequate in terms of target coverage. However, structures that are small in volume or located near the target area showed greater sensitivity to uncertainties., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: Proton therapy (PT) for prostate cancer reduces rectal and bladder dose, but increases dose to the femoral necks. We assessed the risk of hip fracture and pain in men treated with PT for prostate cancer., Material and Methods: From 2006 to 2008, 382 men were treated for prostate cancer and evaluated at six-month intervals after PT for toxicities at University of Florida Proton Therapy Institute (UFPTI). The WHO Fracture Risk Assessment Tool (FRAX) generated annual hip-fracture risk for the cohort. The WHO FRAX tool was utilized to generate the expected number of patients with hip fractures and the observed-to-expected ratio; confidence intervals and p-value were generated with the mid-P exact test. Univariate analysis of hip pain as a function of several prognostic factors was accomplished with Fisher's exact test., Results: Median follow-up was four years (range, 0.1-5.5 years). Per FRAX, 3.02 patients were expected to develop a hip fracture without PT. Three PT patients actually developed fractures for a rate of 0.21 fractures per 100 person-years of follow-up. There was an observed-expected ratio of 0.99 (p-value not significant). Forty-eight patients (13%) reported new pain in the hip during follow-up; three required prescription analgesics., Conclusion: PT for prostate cancer did not increase hip-fractures in the first four years after PT compared to expected rates in untreated men.