Improvements in beam's eye view fiducial tracking using a novel multilayer imager.

Purpose.Electronic portal image devices (EPIDs) have been investigated previously for beams-eye view (BEV) applications such as tumor tracking but are limited by low contrast-to-noise ratio and detective quantum efficiency. A novel multilayer imager (MLI), consisting of four stacked flat-panels was used to measure improvements in fiducial tracking during liver stereotactic body radiation therapy (SBRT) procedures compared to a single layer EPID.Methods.The prototype MLI was installed on a clinical TrueBeam linac in place of the conventional DMI single-layer EPID. The panel was extended during volumetric modulated arc therapy SBRT treatments in order to passively acquire data during therapy. Images were acquired for six patients receiving SBRT to liver metastases over two fractions each, one with the MLI using all 4 layers and one with the MLI using the top layer only, representing a standard EPID. The acquired frames were processed by a previously published tracking algorithm modified to identify implanted radiopaque fiducials. Truth data was determined using respiratory traces combined with partial manual tracking. Results for 4- and 1-layer mode were compared against truth data for tracking accuracy and efficiency. Tracking and noise improvements as a function of gantry angle were determined.Results. Tracking efficiency with 4-layers improved to 82.8% versus 58.4% for the 1-layer mode, a relative improvement of 41.7%. Fiducial tracking with 1-layer returned a root mean square error (RMSE) of 2.1 mm compared to 4-layer RMSE of 1.5 mm, a statistically significant (p < 0.001) improvement of 0.6 mm. The reduction in noise correlated with an increase in successfully tracked frames (r = 0.913) and with increased tracking accuracy (0.927).Conclusion. Increases in MV photon detection efficiency by utilization of a MLI results in improved fiducial tracking for liver SBRT treatments. Future clinical applications utilizing BEV imaging may be enhanced by including similar noise reduction strategies.

A retrospective comparison of neoadjuvant chemoradiotherapy regimens for locally advanced esophageal cancer.

Preoperative chemoradiotherapy (CRT) with carboplatin/paclitaxel has been shown to increase survival in patients with esophageal cancer, including gastroesophageal junction (GE) junction cancer, over surgery alone; however, there have been no studies comparing the different neoadjuvant CRT regimens. We retrospectively evaluated the long-term results of trimodality therapy for patients with locally advanced esophageal cancer treated on several chemotherapy regimens. Between 1999 and 2014, 215 patients with locally advanced esophageal cancer underwent neoadjuvant CRT followed by surgical resection. The median age was 62 years (range 21-84), 80.5% were men and 86% had adenocarcinoma. The following chemotherapy regimens were administered: cisplatin/5FU (14.9%), cisplatin/irinotecan (35.8%), carboplatin/paclitaxel (35.8%), and other (9.7%). The majority of patients (92.1%) received a radiation dose of 50.4 Gy. Predictors of toxicities and surgical complications were assessed using logistic regression. Overall survival (OS) and recurrence-free survival (RFS) were estimated using the Kaplan-Meier method and proportional hazards regression was used to model time-to-event outcomes. The median follow-up among surviving patients was 4.1 years (range 0.4,13). The median OS was 3.0 years from time of diagnosis and OS was 36.8% at 5 years. RFS was 34.9% at 5 years. After neoadjuvant CRT, 34.7% of patients achieved a pathologic complete response including 60.7% of squamous cell carcinoma patients and 18.4% of adenocarcinoma patients (P < 0.001) and 66% were downstaged. Of the variables examined, pathologic stage, preoperative baseline cardiac comorbidity, postoperative cardiac or pulmonary complications, and chemotherapy regimen were associated with OS. Using cisplatin and 5FU as the reference regimen, patients treated with carboplatin/paclitaxel had significantly improved OS (HR = 0.47, P = 0.017 after adjusting for surgery type, radiation modality, baseline cardiac comorbidity, and preoperative stage) with 5-year OS rate of 66%. The most common surgical complications were cardiac in 61 patients (28.5%) and pulmonary in 52 patients (24.3%). Cardiac complications were associated with age (OR 1.05, P = 0.007) and cardiac comorbidity (OR 2.6, P = 0.02) and pulmonary complications with female gender (OR 3.98, P < 0.001). Forty-four patients (20.5%) required readmission within 30 days of discharge, and readmission was associated with cardiac comorbidity (OR 2.7, P = 0.017). Three patients died within 30 days of surgery. We observed an association between neoadjuvant carboplatin/paclitaxel and improved overall survival that requires confirmation in a prospective randomized trial.

Racial disparities in prostate cancer outcome among prostate-specific antigen screening eligible populations in the United States.

Background: In 2012, the United States Preventive Services Task Force (USPSTF) recommended against prostate-specific antigen (PSA) screening, despite evidence that Black men are at a higher risk of prostate cancer-specific mortality (PCSM). We evaluated whether Black men of potentially screening-eligible age (55-69 years) are at a disproportionally high risk of poor outcomes. Patients and methods: The SEER database was used to study 390 259 men diagnosed with prostate cancer in the United States between 2004 and 2011. Multivariable logistic regression modeled the association between Black race and stage of presentation, while Fine-Gray competing risks regression modeled the association between Black race and PCSM, both as a function of screening eligibility (age 55-69 years versus not). Results: Black men were more likely to present with metastatic disease (adjusted odds ratio [AOR] 1.65; 1.58-1.72; P < 0.001) and were at a higher risk of PCSM (adjusted hazard ratio [AHR] 1.36; 1.27-1.46; P < 0.001) compared to non-Black men. There were significant interactions between race and PSA-screening eligibility such that Black patients experienced more disproportionate rates of metastatic disease (AOR 1.76; 1.65-1.87 versus 1.55; 1.47-1.65; Pinteraction < 0.001) and PCSM (AHR 1.53; 1.37-1.70 versus 1.25; 1.14-1.37; Pinteraction = 0.01) in the potentially PSA-screening eligible group than in the group not eligible for screening. Conclusions: Racial disparities in prostate cancer outcome among Black men are significantly worse in PSA-screening eligible populations. These results raise the possibility that Black men could be disproportionately impacted by recommendations to end PSA screening in the United States and suggest that Black race should be included in the updated USPSTF PSA screening guidelines.

Utilization of biopsy-based genomic classifier to predict distant metastasis after definitive radiation and short-course ADT for intermediate and high-risk prostate cancer.

BACKGROUND: We examined the ability of a biopsy-based 22-marker genomic classifier (GC) to predict for distant metastases after radiation and a median of 6 months of androgen deprivation therapy (ADT). METHODS: We studied 100 patients with intermediate-risk (55%) and high-risk (45%) prostate cancer who received definitive radiation plus a median of 6 months of ADT (range 3-39 months) from 2001-2013 at a single center and had available biopsy tissue. Six to ten 4 micron sections of the needle biopsy core with the highest Gleason score and percentage of tumor involvement were macrodissected for RNA extraction. GC scores (range, 0.04-0.92) were determined. The primary end point of the study was time to distant metastasis. Median follow-up was 5.1 years. There were 18 metastases during the study period. RESULTS: On univariable analysis (UVA), each 0.1 unit increase in GC score was significantly associated with time to distant metastasis (hazard ratio: 1.40 (1.10-1.84), P=0.006) and remained significant after adjusting for clinical variables on multivariable analysis (MVA) (adjusted hazard ratio: 1.36 (1.04-1.83), P=0.024). The c-index for 5-year distant metastasis was 0.45 (95% confidence interval: 0.27-0.64) for Cancer of the Prostate Risk Assessment score, 0.63 (0.40-0.78) for National Comprehensive Cancer Network (NCCN) risk groups, and 0.76 (0.57-0.89) for the GC score. Using pre-specified GC risk categories, the cumulative incidence of metastasis for GC>0.6 reached 20% at 5 years after radiation (P=0.02). CONCLUSIONS: We believe this is the first demonstration of the ability of the biopsy-based GC score to predict for distant metastases after definitive radiation and ADT for intermediate- and high-risk prostate cancer. Patients with the highest GC risk (GC>0.6) had high rates of metastasis despite multi-modal therapy suggesting that they could potentially be candidates for treatment intensification and/or enrollment in clinical trials of novel therapy.

Incidence and determinants of 1-month mortality after cancer-directed surgery.

BACKGROUND: Death within 1 month of surgery is considered treatment related and serves as an important health care quality metric. We sought to identify the incidence of and factors associated with 1-month mortality after cancer-directed surgery. PATIENTS AND METHODS: We used the Surveillance, Epidemiology and End Results Program to study a cohort of 1 110 236 patients diagnosed from 2004 to 2011 with cancers that are among the 10 most common or most fatal who received cancer-directed surgery. Multivariable logistic regression analyses were used to identify factors associated with 1-month mortality after cancer-directed surgery. RESULTS: A total of 53 498 patients (4.8%) died within 1 month of cancer-directed surgery. Patients who were married, insured, or who had a top 50th percentile income or educational status had lower odds of 1-month mortality from cancer-directed surgery {[adjusted odds ratio (AOR) 0.80; 95% confidence interval (CI) 0.79-0.82; P < 0.001], (AOR 0.88; 95% CI 0.82-0.94; P < 0.001), (AOR 0.95; 95% CI 0.93-0.97; P < 0.001), and (AOR 0.98; 95% CI 0.96-0.99; P = 0.043), respectively}. Patients who were non-white minority, male, or older (per year increase), or who had advanced tumor stage 4 disease all had a higher risk of 1-month mortality after cancer-directed surgery, with AORs of 1.13 (95% CI 1.11-1.15), P < 0.001; 1.11 (95% CI 1.08-1.13), P < 0.001; 1.02 (95% 1.02-1.03), P < 0.001; and 1.89 (95% CI 1.82-1.95), P < 0.001 respectively. CONCLUSIONS: Unmarried, uninsured, non-white, male, older, less educated, and poorer patients were all at a significantly higher risk for death within 1 month of cancer-directed surgery. Efforts to reduce 1-month surgical mortality and eliminate sociodemographic disparities in this adverse outcome could significantly improve survival among patients with cancer.

The association between insurance status and prostate cancer outcomes: implications for the Affordable Care Act.

BACKGROUND: The Affordable Care Act (ACA) aims to expand health insurance coverage to over 30 million previously uninsured Americans. To help evaluate the potential impact of the ACA on prostate cancer care, we examined the associations between insurance coverage and prostate cancer outcomes among men <65 years old who are not yet eligible for Medicare. METHODS: The Surveillance, Epidemiology and End Results Program was used to identify 85 203 men aged <65 years diagnosed with prostate cancer from 2007 to 2010. Multivariable logistic regression modeled the association between insurance status and stage at presentation. Among men with high-risk disease, the associations between insurance status and receipt of definitive therapy, prostate cancer-specific mortality (PCSM) and all-cause mortality were determined using multivariable logistic, Fine and Gray competing-risks and Cox regression models, respectively. RESULTS: Uninsured patients were more likely to be non-white and come from regions of rural residence, lower median household income and lower education level (P<0.001 for all cases). Insured men were less likely to present with metastatic disease (adjusted odds ratio (AOR) 0.23; 95% confidence interval (CI) 0.20-0.27; P<0.001). Among men with high-risk disease, insured men were more likely to receive definitive treatment (AOR 2.29; 95% CI 1.81-2.89; P<0.001), and had decreased PCSM (adjusted hazard ratio 0.56; 95% CI 0.31-0.98; P=0.04) and all-cause mortality (adjusted hazard ratio 0.60; 0.39-0.91; P=0.01). CONCLUSIONS: Insured men with prostate cancer are less likely to present with metastatic disease, more likely to be treated if they develop high-risk disease and are more likely to survive their cancer, suggesting that expanding health coverage under the ACA may significantly improve outcomes for men with prostate cancer who are not yet eligible for Medicare.

Mirabegron for the treatment of overactive bladder: a prespecified pooled efficacy analysis and pooled safety analysis of three randomised, double-blind, placebo-controlled, phase III studies.

INTRODUCTION: To examine pooled efficacy data from three, large phase III studies comparing mirabegron (50 and 100 mg) with placebo, and pooled safety data including additional mirabegron 25 mg and tolterodine extended release (ER) 4 mg results. METHODS: This prespecified pooled analysis of three randomised, double-blind, placebo-controlled, 12-week studies, evaluated efficacy and safety of once-daily mirabegron 25 mg (safety analysis), 50 or 100 mg (efficacy and safety analyses) and tolterodine ER 4 mg (safety analysis) for the treatment of symptoms of overactive bladder (OAB). Co-primary efficacy measures were change from baseline to Final Visit in the mean number of incontinence episodes/24 h and mean number of micturitions/24 h. Key secondary efficacy end-points included mean number of urgency episodes/24 h and mean volume voided/micturitions, while other end-points included patient-reported outcomes according to the Treatment Satisfaction-Visual Analogue Scale (TS-VAS) and responder analyses [dry rate (posttreatment), ≥ 50% reduction in incontinence episodes/24 h, ≤ 8 micturitions/24 h (post hoc analysis)]. The safety analysis included adverse event (AE) reporting, laboratory assessments, ECG, postvoid residual volume and vital signs (blood pressure, pulse rate). RESULTS: Mirabegron (50 and 100 mg once daily) demonstrated statistically significant improvements compared with placebo for the co-primary end-points, key secondary efficacy variables, TS-VAS and responder analyses (all comparisons p < 0.05). Mirabegron is well tolerated and demonstrates a good safety profile. The most common AEs (≥ 3%) included hypertension, nasopharyngitis and urinary tract infection (UTI); the incidence of hypertensive events and UTIs decreased with increasing dose. For mirabegron, the incidence of the bothersome antimuscarinic AE, dry mouth, was at placebo level and of a lesser magnitude than tolterodine. CONCLUSION: The efficacy and safety of mirabegron are demonstrated in this large pooled clinical trial dataset in patients with OAB.

Pegylation: a novel process for modifying pharmacokinetics.

The use of liposomal carriers and the modification of therapeutic molecules through the attachment of poly(ethylene glycol) [PEG] moieties ('pegylation') are the most common approaches for enhancing the delivery of parenteral agents. Although 'classical' liposomes (i.e. phospholipid bilayer vehicles) have been effective in decreasing the clearance of encapsulated agents and in passively targeting specific tissues, they are associated with considerable limitations. Pegylation may be an effective method of delivering therapeutic proteins and modifying their pharmacokinetic properties, in turn modifying pharmacodynamics, via a mechanism dependent on altered binding properties of the native protein. Pegylation reduces renal clearance and, for some products, results in a more sustained absorption after subcutaneous administration as well as restricted distribution. These pharmacokinetic changes may result in more constant and sustained plasma concentrations, which can lead to increases in clinical effectiveness when the desired effects are concentration-dependent. Maintaining drug concentrations at or near a target concentration for an extended period of time is often clinically advantageous, and is particularly useful in antiviral therapy, since constant antiviral pressure should prevent replication and may thereby suppress the emergence of resistant variants. Additionally, PEG modification may decrease adverse effects caused by the large variations in peak-to-trough plasma drug concentrations associated with frequent administration and by the immunogenicity of unmodified proteins. Pegylated proteins may have reduced immunogenicity because PEG-induced steric hindrance can prevent immune recognition. Two PEG-modified proteins are currently approved by the US Food and Drug Administration; several others, including cytokines such as interferon-alpha (IFNalpha), growth factors and free radical scavengers, are under development. Careful assessment of various pegylated IFNalpha products suggests that pegylated molecules can be differentiated on the basis of their pharmacokinetic properties and related changes in pharmacodynamics. Because the size, geometry and attachment site of the PEG moiety play a crucial role in determining these properties, therapeutically optimised agents must be designed on a protein-by-protein basis.

Oxidant stress responses in premature infants during exposure to hyperoxia.

To assess oxidant stress responses in newborn infants treated with elevated concentrations of oxygen, we measured plasma concentrations of glutathione (GSH) and glutathione disulfide (GSSG) in newborn infants ranging from 23 to 42 wk gestational age. All infants recruited into the study were mechanically ventilated and had catheters placed in their umbilical arteries as part of their normal clinical management. Blood samples were obtained on d 1, 3, and 5 and weekly thereafter or until the catheters were removed. We observed plasma concentrations of GSSG in these infants that were frequently an order of magnitude higher than the 0.1 to 0.3 microM we find in adults. Interestingly, plasma GSSG concentrations were inversely correlated to the inspired oxygen tensions. This effect appeared to arise from the patient selection criteria whereby, of the infants studied, those breathing the lowest partial pressures of oxygen were the smallest and gestationally youngest. A second observation was that plasma concentrations of GSH in the premature infants were substantially, indeed often dramatically, lower than we have observed in adult humans (6 to 10 microM). Finally, we found that in patients with both umbilical arterial and umbilical venous catheters arterial GSSG concentrations were consistently higher than venous concentrations; conversely, arterial GSH concentrations were lower than venous concentrations. The elevated GSSG concentrations we observed in these infants indicate marked oxidant stress responses in prematurely born infants, even in those infants exposed only to room air. The positive arteriovenous gradients of GSSG concentrations across the lungs of these infants suggest that at least some of the increased plasma GSSG originates in the lung.(ABSTRACT TRUNCATED AT 250 WORDS)