A pair of deep learning auto-contouring models for prostate cancer patients injected with a radio-transparent versus radiopaque hydrogel spacer.

BACKGROUND: Absorbable hydrogel spacer injected between prostate and rectum is gaining popularity for rectal sparing. The spacer alters patient anatomy and thus requires new auto-contouring models. PURPOSE: To report the development and comprehensive evaluation of two deep-learning models for patients injected with a radio-transparent (model I) versus radiopaque (model II) spacer. METHODS AND MATERIALS: Model I was trained and cross-validated by 135 cases with transparent spacer and tested on 24 cases. Using refined training methods, model II was trained and cross-validated by the same dataset, but with the Hounsfield Unit distribution in the spacer overridden by that obtained from ten cases with opaque spacer. Model II was tested on 64 cases. The models auto-contour eight regions of interest (ROIs): spacer, prostate, proximal seminal vesicles (SVs), left and right femurs, bladder, rectum, and penile bulb. Qualitatively, each auto contour (AC), as well as the composite set, was assessed against manual contour (MC), by a radiation oncologist using a 1 (accepted directly or after minor editing), 2 (accepted after moderate editing), 3 (accepted after major editing), and 4 (rejected) scoring scale. The efficiency gain was characterized by the mean score as nearly complete [1-1.75], substantial (1.75-2.5], meaningful (2.5-3.25], and no (3.25-4.00]. Quantitatively, the geometric similarity between AC and MC was evaluated by dice similarity coefficient (DSC) and mean distance to agreement (MDA), using tolerance recommended by AAPM TG-132 Report. The results by the two models were compared to examine the outcome of the refined training methods. The large number of testing cases for model II allowed further investigation of inter-observer variability in clinical dataset. The correlation between score and DSC/MDA was studied on the ROIs with 10 or more counts of each acceptable score (1, 2, 3). RESULTS: For model I/model II: the mean score was 3.63/1.30 for transparent/opaque spacer, 2.71/2.16 for prostate, 3.25/2.44 for proximal SVs, 1.13/1.02 for both femurs, 2.25/1.25 for bladder, 3.00/2.06 for rectum, 3.38/2.42 for penile bulb, and 2.79/2.20 for the composite set; the mean DSC was 0.52/0.84 for spacer, 0.84/0.85 for prostate, 0.60/0.62 for proximal SVs, 0.94/0.96 for left femur, 0.95/0.96 for right femur, 0.91/0.95 for bladder, 0.81/0.84 for rectum, and 0.65/0.65 for penile bulb; and the mean MDA was 2.9/0.9 mm for spacer, 1.9/1.7 mm for prostate, 2.4/2.3 mm for proximal SVs, 0.8/0.5 mm for left femur, 0.7/0.5 mm for right femur, 1.5/0.9 mm for bladder, 2.3/1.9 mm for rectum, and 2.2/2.2 mm for penile bulb. Model II showed significantly improved scores for all ROIs, and metrics for spacer, femurs, bladder, and rectum. Significant inter-observer variability was only found for prostate. Highly linear correlation between the score and DSC was found for the two qualified ROIs (prostate and rectum). CONCLUSIONS: The overall efficiency gain was meaningful for model I and substantial for model II. The ROIs meeting the clinical deployment criteria (mean score below 3.25, DSC above 0.8, and MDA below 2.5 mm) included prostate, both femurs, bladder and rectum for both models, and spacer for model II.

Effect of Radiation Treatment at a High-Volume Center on Outcomes in Intermediate-Risk Prostate Cancer: An Analysis of the National Cancer Database.

OBJECTIVE: To investigate the effect of radiation treatment at a high-volume center on overall survival in men with intermediate-risk prostate cancer. METHODS: From 2004 to 2015, 430,347 patients with intermediate-risk prostate cancer were identified in the National Cancer Database. Radiation case volume (RCV) of each hospital was calculated based on number of patients treated. After excluding certain patients including those with metastatic disease, our final analysis population included 116,091 intermediate-risk prostate cancer patients receiving radiation therapy or radiation with androgen deprivation therapy. Characteristics analyzed include age, race, distance to treatment facility, Charlson-Deyo Score, and socioeconomic factors. Primary outcome was overall survival (OS). Five-year survival rates were estimated using the Kaplan-Meier method. Adjusted hazard ratios with 95% confidence intervals were computed using multivariate analysis. Cox regression and propensity score-matched analysis was performed. RESULTS: Median follow up was 63.5 months and estimated 5-year OS was 90.1% at high RCV centers and 88.2% at low RCV centers (P <.0001). Treatment at high RCV facility was associated with significantly lower mortality compared to treatment at a low RCV facility on multivariate analysis and propensity score matching analysis. The survival benefit of treatment at a high RCV facility remained when high RCV facilities were defined as those above the 80th, 90th, and 95th percentile in patient volume (P <.05). CONCLUSION: Treatment at a high radiation case volume facility is associated with improved OS in patients with radiation-treated intermediate-risk prostate cancer. This survival benefit is important to consider when choosing a treatment center for radiation therapy.

Outcomes for Young Men With Localized Intermediate-Risk Prostate Cancer: An Analysis of the NCDB.

BACKGROUND: Primary management of localized, intermediate-risk prostate cancer consists of radical prostatectomy (RP), radiotherapy (RT) with short-course androgen deprivation therapy (ADT), or RT alone. The purpose of this study was to determine if these treatment strategies have equivalent overall survival (OS) in patients < 55 years old with intermediate-risk prostate cancer. PATIENTS AND METHODS: We identified 35,134 patients in the National Cancer Data Base with localized intermediate-risk prostate cancer treated with RP, RT + ADT, or RT from 2004 to 2013. Ten-year OS rates were estimated by the Kaplan-Meier method. Adjusted hazard ratios (HR) with 95% confidence intervals (CI) were computed by multivariate Cox regression. RESULTS: A total of 29,920 patients (85.2%) underwent RP, 1393 (4.0%) RT + ADT, and 3821 (10.9%) RT. Median patient age was 51 years old, and median follow-up was 59.9 months. Ten-year OS was estimated to be 94.2% for RP, 80.7% for RT + ADT, and 85.2% for RT (P < .0001). On multivariate analysis, treatment with RT + ADT or RT was associated with significantly worse OS compared to treatment with RP (RT + ADT HR = 2.06, 95% CI 1.67-2.54, P < .0001; RT HR = 2.0, 95% CI 1.71-2.33, P < .0001). Patients who met all 3 of the intermediate-risk criteria showed worse OS compared to patients who met only one criterion (HR = 1.80; 95% CI, 1.32-2.44; P = .0002). CONCLUSION: RP is significantly more likely than RT + ADT or RT to be used as a primary treatment for young men with localized intermediate prostate cancer. RP was also associated with improved OS compared to RT + ADT and RT.

The Radiation Oncology Mentorship Initiative: Analysis of a Formal Mentoring Initiative for Medical Students Interested in Radiation Oncology.

The importance of mentorship in medicine and its impact on academic and professional development has been widely studied. However, mentorship for medical students in the field of radiation oncology is limited. Our radiation oncology department developed a formal medical student mentorship program in 2004. This program included both clinical and research mentoring pathways. Our study aims to gain feedback and perspective from former medical student participants who subsequently entered into a radiation oncology residency program. An anonymous survey was sent to 22 former students in the mentorship program from 2005 to 2016 who entered a radiation oncology residency program. The survey included Likert scales (1-5), multiple choice, strength category rankings, and free responses. Data was compiled and analyzed with Qualtrics data software. The survey response rate was 100%. Seventeen (77.3%) participants reported that the mentorship program strongly affected their career choice and a majority reported that their research experience strongly (45.5%) or moderately affected (31.8%) their career choice. Fourteen (63.6%) respondents reported that the mentorship program was very effective and 8 (36.4%) reported it as being effective. Eighteen (81.8%) respondents reported that mentorship was extremely important to their career. Students participating in the research pathway also reported improvement in valuable skills such as presentations, abstract writing, manuscript writing, statistical analysis, and coordination with colleagues. A total of 66.7% of attending radiation oncologists who previously participated in this program now practice in an academic setting. Our institution successfully developed a formalized mentorship program for medical students interested in radiation oncology. Participants in this program reported high levels of satisfaction and emphasized the importance of mentorship in the development of valuable research competencies and on their overall career path. This program can serve as a model for future mentorship initiative in medical school.

Right heart catheterization using antecubital venous access: feasibility, safety and adoption rate in a tertiary center.

OBJECTIVES: To determine feasibility, safety, and adoption rates of right heart catheterization (RHC) using antecubital venous access (AVA) as compared to using the traditional approach of proximal venous access (PVA). BACKGROUND: RHC via PVA (i.e., internal jugular, femoral or subclavian) is generally a low risk procedure; however, complications may occur and are usually access site related. RHC via an antecubital approach has regained attention given the increase in transradial left heart catheterizations. METHODS: Patients undergoing RHC for any indication at a single large academic medical center were identified over a 5-year period (January 2008 to December 2012) from a database. Medical records were retrospectively analyzed for demographic, procedural and outcomes data. RESULTS: Two hundred seventy-two RHC procedures were included (106 AVA, 166 PVA). The adoption rate of AVA for RHC increased rapidly since its introduction in our laboratory in 2010 (100% PVA in 2008 and 2009, 85% AVA in 2012). All procedures were successful; however, 6% of procedures required additional, alternate access to the original site. Initial success rates were similar in the two groups (91 vs. 96% for AVA and PVA respectively, P = 0.12). Fluoroscopy time was shorter in the group of patients who underwent the procedure via AVA. The complication rate was 0% in the AVA group compared with 3% in the PVA group (P = 0.16). CONCLUSION: RHC via the AVA is a feasible and safe alternative to PVA. Our experience and rapid adoption support the use AVA as the access site of choice for RHC in uncomplicated patients.

The body, its emotions, the self, and consciousness.

This article proposes a means for better understanding the self and consciousness. Data indicate that the basic "emotional brain" continually computes potential survival risk against reward to rank consequent "emotion scores" for all sensory inputs. These scores compete to yield winner-takes-all outcomes that determine the choice of attention or action. This mechanism prevails regardless of whether the competing options gain their emotion scores through a rational or an intuitive pathway. There is no need to postulate any homunculus or inner self in control of such choice; indeed, our belief in a first-person self in overall control is wrong. The self is a passive construct arising from each individual's social development, where language acquisition vastly heightens communication and awareness not only outwardly, but also inwardly, as if to a controlling "inner I." However, when society comes to hold the maturing being accountable for his or her actions, the brain must respond, and it does so in the only way it can, by deeming that this passive, inner self-construct act as if it were the active self in charge. Consciousness emerges when the language-based output of the higher brain is referred for ownership to this artificial self-construct.