Use of a tissue biomarker panel to predict which men with a rising PSA post-definitive prostate cancer therapy will have systemic progression

5017

Background: The majority of men with prostate cancer are diagnosed with cancers with low mortality. Such men are treated with radical prostatectomy, external beam radiotherapy, or brachytherapy and followed by serum PSA evaluations. Some men with a rising PSA therapy will have local recurrence or metastasis, but many will have no other evidence of recurrent disease other than a rising PSA. The PSA doubling time has been used to determine which of these men deserve adjuvant hormonal ablation, radiation therapy, or observation. We hypothesize that additional biomarkers will predict which men with a rising PSA post-definitive therapy would benefit from additional therapy. Methods: We designed a custom array containing 526 RNA targets whose expression has been reported to be altered in association with prostate cancer progression. We included targets from Mayo Clinic prostate cancer research. Together with a second commercial array, 530 genes implicated in prostate cancer progression and 420 other cancer-related genes were evaluated. A case-control design was used to test the association of the expression results with outcome. Cases were men post-radical prostatectomy who developed systemic progression within 5 years after PSA recurrence (N=213). Controls were matched men post-radical prostatectomy with PSA recurrence but no evidence of clinical progression within 5 years (N=213). Results: Of 426 eligible patients, paraffin blocks were available on 418 (98.1%). RNA was prepared from all 418 blocks, and both arrays were both successful on 405 (96.9%) RNAs. Upon univariate analysis, 40 genes were highly significantly over- or under-expressed in the cases versus controls (1x10-22 < p < 1x10-7). Recursive partitioning (RP) selected 4 genes (TPX2, FAM13C1, TOPO2A and TSP2) that distinguished cases from controls. Random Forest analysis selected 24 genes (including 3 of the RP 4). A multivariable ROC analysis using these 24 genes generated an AUC of 0.80 (95% CI: 0.75–0.84). Conclusions: A specific gene expression pattern was significantly associated with systemic progression after PSA recurrence. The measurement of gene expression pattern may be useful for determining which men may benefit from additional therapy after PSA recurrence.

No significant financial relationships to disclose.

An analysis quantifies prostate brachytherapy swelling using peripheral seeds as fiducial reference points

15639

Background: Permanent prostate brachytherapy (PPB) assesses implant quality but may suffer significant variability due to: 1) Prostate edema may occur during the procedure which usually subsides within several months, and 2) interobserver variability of CT- derived prostate volumes. An analysis is described, which uses the seeds as prostate fiducials to produce an implant reference volume (IRV). The ratio of the IRV volumes at day 0 and day 33 provides a unique way to quantify prostate edema; thus reducing this factor as a source of variability. Methods: Thirteen low risk prostate cancer patients, (Stage ≤ T2, PSA<13.9, Gleason Score ≤7) were implanted with 125Iodine seeds (77% stranded; prescription dose of 145 Gy). PPB was completed for each patient on day 0 and 33 ±3 days following the implant. The IRV was defined as the volume obtained by contouring the outer most peripheral seeds, circumferentially, on each axial image, resulting in a 3D volume. Contouring was performed by three separate investigators (KJM, DCG, EKM), who were blinded with respect to patient identification. The IRV's were compared both by investigator and by time of PPB (day 0 vs. day 33). The radiation dose encompassing 90% (D90) of the IRV and Prostate (PST) was calculated and compared . Results: The IRVs contoured were reproducible between the investigators with a maximum mean difference of .56 (SD .33) cc. There was no statistical difference between any of the investigators contoured volume (minimum Spearman correlation was 0.978). The average IRV was significantly larger on day 0 (Avg. 52.7;SD 19.7 cc) compared to day 33 (Avg. 44.6; SD 19.1 cc) (p<0.001). The day 0 IRV was an average of 1.18 times larger than the Day 33 PRV. There was no difference between either the day 0 D90PST (Avg.149.1; SD18.7 cGy) vs the day 0 D90IRV (Avg.149.8, SD 27.5 cGy) (p=.442) nor between the day 33 D90PST (Avg.163.7; SD22.7 cGy) vs the day 33 D90IRV (Avg.166.6, SD 30.3 cGy) (p=.257). Both the D90IRV and D90PST were significantly different at day 0 vs 33 (p=.0003, p=<.0001 respectively). Conclusions: The IRV analysis demonstrates no significant interobserver variability, provides accurate quantification of prostate swelling after PPB, and is an accurate objective surrogate analysis for PSI quality.

No significant financial relationships to disclose.

Damköhler number design method to avoid clogging of subsurface flow constructed wetlands by heterotrophic biofilms

Clogging of subsurface flow (SSF) treatment wetlands from excess biofilm growth is a design problem for which only empirical guidelines exist. A method is proposed to systematically analyse this type of clogging as a design tool. In recognition of the physical reality that most SSF treatment wetland processes are a function of biofilm surface area, a Damköhler number (Da) definition based on aggregate specific surface area is used to investigate a method of predicting clogging induced by heterotrophic biofilms growing on treatment media.

Effects of feeding strategy and age on live animal performance, carcass characteristics, and economics of short-term feeding programs for culled beef cows

To evaluate production and economic effects of feeding management strategy and age on intensively managed culled beef cows, a study was conducted using 125 cows of British breeding blocked by age (Young = 3 and 4 yr olds; LowMid = 5 and 6 yr olds; HighMid = 7 and 8 yr olds; and Aged = 9 yr and older) and assigned to one of three steam-flaked corn based feeding strategies. Treatments were as follows: Conservative (CSV), 30% roughage throughout; Standard (STD), decrease roughage from 30 to 10% over 20 d; and Aggressive (AGR), decrease roughage from 30 to 10% over 10 d. There were four pens per treatment in a randomized complete block design. Cows were fed for a total of 54 d, and BW was measured on d 0, 14, 28, 42, and 54. Half the cows from each pen were randomly selected and slaughtered at a commercial abattoir, and carcass data were collected. Average daily gain, daily DMI, and G:F during each weigh period and across the entire feeding period were calculated. Over the 54-d feeding period, strategies that employed more energy-dense diets numerically increased ADG (1.28, 1.63, and 1.55 +/- 0.14 kg/d for CSV, STD, and AGR; P = 0.26) and decreased DMI (11.91, 10.74, and 10.89 +/- 0.27 kg/d for CSV, STD, and AGR; P = 0.05), such that G:F was lower for CSV than for STD or AGR (0.105, 0.150, and 0.141 +/- 0.010; P = 0.05). Carcass weight was least for the CSV strategy (298 kg) and greatest for STD (328 kg); AGR resulted in intermediate carcass weight (317 +/- 6 kg; P = 0.04). Total cost of gain was over 30% greater for CSV strategy than for STD or AGR strategies (P < 0.01). In many cases, block effects (age) had a greater effect on responses than treatments. Average daily gain, DMI, and G:F decreased linearly with age (P < 0.01). Hot carcass weight, dressing percent, and fat thickness decreased linearly with age (P < 0.03); yield grade decreased and carcass maturity attributes increased linearly with age (P < 0.02). Performance and intake differences resulted in linear increases in total cost of gain (P < 0.01) and breakeven price (P = 0.03) with increasing age. These data indicate advantages to more aggressive feeding management strategies for culled beef cows, although maximal intake may be achieved with higher-roughage diets. Despite management effects, an increase in market price above purchase price may be required for intensive feeding of culled beef cows to be a profitable enterprise.

Utility of bortezomib retreatment among patients with refractory multiple myeloma

17549

Background: Bortezomib (VELCADE; Vc) has emerged as the standard of care for patients with relapsed or refractory multiple myeloma (MM). However, following initial Vc therapy, its utility in recurrent disease is unclear. This retrospective case series provides preliminary evidence of the safety and efficacy of Vc in the retreatment of patients with recurrent MM. Methods: An observational case series was developed based on a medical records review of all patients (N = 10) who completed Vc retreatment following completion of initial Vc therapy. Best response was measured as the greatest mean % reduction in the treatment response measure: serum/urine M-protein or plasma cells. Differences between initial treatment and retreatment efficacy and Vc-related hospitalizations were assessed using descriptive statistics. Results: During initial treatment 44% of patients responded to Vc (≥50% M-protein (3/9) or plasme cell reduction (1/9, 1 pt NA). At retreatment 50% of patients responded (5/10). Following initial Vc therapy, the median treatment-free interval was just over 13 months (56.6 weeks). One patient experienced a dose reduction due to peripheral neuropathy (grade 2) during retreatment, compared to two patients with neuropathy (grade 3) during initial treatment. Termination of therapy due to any unmanageable toxicity was much lower during retreatment (14.3% vs 62.5%). Finally, none of the patients were hospitalized for Vc-related events during retreatment, compared with two patients during initial treatment. Conclusions: Vc retreatment appears to be as effective as initial treatment in terms of response, and may actually yield less toxicity and hospitalizations. Even though this small sample size precluded statistical testing, the observed patterns are instructive and additional prospective trials are currently ongoing. However, based on these preliminary data, prolonged disease control may be achieved with repeated use.

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Thiobarbituric Acid Reactive Substances and Volatile Compounds in Chicken Breast Meat Infused with Plant Extracts and Subjected to Electron Beam Irradiation

The effect of irradiation on thiobarbituric acid reactive substances (TBARS) and volatile compounds in raw and cooked nonirradiated and irradiated chicken breast meat infused with green tea and grape seed extracts was investigated. Chicken breast meat was vacuum infused with green tea extract (3,000 ppm), grape seed extract (3,000 ppm), or their combination (at a total of 6,000 ppm), irradiated with an electron beam, and stored at 5 degrees C for 12 d. The targeted irradiation dosage was 3.0 kGy and the average absorbed dosage was 3.12 kGy. Values of TBARS and volatile compound contents of raw and cooked chicken meat were determined during the 12-d storage period. Thiobarbituric acid reactive substances values ranged from 15.5 to 71.4 mg of malondialdehyde/kg for nonirradiated raw chicken and 17.3 to 80.1 mg of malondialdehyde/kg for irradiated raw chicken. Values for cooked chicken ranged from 31.4 to 386.2 and 38.4 to 504.1 mg of malondialdehyde/kg for nonirradiated and irradiated chicken, respectively. Irradiation increased TBARS and hexanal values of controls and meat infused with plant extracts. Hexanal had the highest intensity of volatiles followed by pentanal and other volatiles. Cooking the samples significantly (P < 0.05) increased the amounts of TBARS and volatiles. Addition of plant extracts decreased the amount of TBARS as well as hexanal and pentanal values. Although irradiation increases lipid oxidation, infusion of chicken meat with plant extracts could reduce lipid oxidation caused by irradiation.

Evaluation of an automated deformable image matching method for quantifying lung motion in respiration-correlated CT images

We have evaluated an automated registration procedure for predicting tumor and lung deformation based on CT images of the thorax obtained at different respiration phases. The method uses a viscous fluid model of tissue deformation to map voxels from one CT dataset to another. To validate the deformable matching algorithm we used a respiration-correlated CT protocol to acquire images at different phases of the respiratory cycle for six patients with nonsmall cell lung carcinoma. The position and shape of the deformable gross tumor volumes (GTV) at the end-inhale (EI) phase predicted by the algorithm was compared to those drawn by four observers. To minimize interobserver differences, all observers used the contours drawn by a single observer at end-exhale (EE) phase as a guideline to outline GTV contours at EI. The differences between model-predicted and observer-drawn GTV surfaces at EI, as well as differences between structures delineated by observers at EI (interobserver variations) were evaluated using a contour comparison algorithm written for this purpose, which determined the distance between the two surfaces along different directions. The mean and 90% confidence interval for model-predicted versus observer-drawn GTV surface differences over all patients and all directions were 2.6 and 5.1 mm, respectively, whereas the mean and 90% confidence interval for interobserver differences were 2.1 and 3.7 mm. We have also evaluated the algorithm's ability to predict normal tissue deformations by examining the three-dimensional (3-D) vector displacement of 41 landmarks placed by each observer at bronchial and vascular branch points in the lung between the EE and EI image sets (mean and 90% confidence interval displacements of 11.7 and 25.1 mm, respectively). The mean and 90% confidence interval discrepancy between model-predicted and observer-determined landmark displacements over all patients were 2.9 and 7.3 mm, whereas interobserver discrepancies were 2.8 and 6.0 mm. Paired t tests indicate no significant statistical differences between model predicted and observer drawn structures. We conclude that the accuracy of the algorithm to map lung anatomy in CT images at different respiratory phases is comparable to the variability in manual delineation. This method has therefore the potential for predicting and quantifying respiration-induced tumor motion in the lung.

Ethnic differences in the relationships between obesity and glucose-metabolic abnormalities: a cross-sectional population-based study

OBJECTIVES

To evaluate whether body mass index (BMI) and other anthropometric indices of visceral obesity vary by ethnic group in their distribution and their relationship to metabolic abnormalities.

DESIGN

Cross-sectional study.

PARTICIPANTS

Canadian men and women, aged 35-75 years, of South Asian (n=342), Chinese (n=317), European (n=326) and Aboriginal (n=301) descent were recruited using stratified random sampling.

PRIMARY MEASURES

Anthropometric indices (BMI, waist to hip ratio (WHR) and waist circumference (WC)), metabolic markers (fasting glucose, HbA1c, the ratio of total cholesterol/HDL) and clinical markers (systolic blood pressure) were assessed.

RESULTS

In subjects with BMI<30 kg/m2, the mean marker levels in people with elevated WC (>88 cm in women, >102 cm in men) vs people with normal WC were 6.16 vs 5.34 mmol/l for fasting glucose, 6.05 vs 5.66% for HbA1c and 5.46 vs 4.68 for the ratio of total cholesterol to HDL (P<0.001 in each case). At nearly every given level of BMI, non-European ethnic groups displayed significantly higher marker levels than Europeans. For example, for a given BMI, age and sex, the difference between European and non-European groups in HbA1c levels was 0.53% (95% confidence interval (CI): 0.37-0.69) for South Asians, 0.37% (95% CI: 0.2-0.54) for Chinese and 0.95% (95% CI: 0.78-1.12) for Aboriginal People.

CONCLUSIONS

Uniform cut-points for the classification of obesity using BMI, WHR or WC result in marked variation in the levels of glucose-metabolic abnormalities between ethnic groups. Existing action thresholds for these anthropometric indices do not apply to non-European ethnic groups and warrant revision.