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- Mattsson, Niklas, 1979, et al.
(författare)
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CSF biomarker variability in the Alzheimer's Association quality control program
- 2013
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Ingår i: Alzheimers & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 9:3, s. 251-261
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Tidskriftsartikel (refereegranskat)abstract
- Background The cerebrospinal fluid (CSF) biomarkers amyloid beta 1–42, total tau, and phosphorylated tau are used increasingly for Alzheimer's disease (AD) research and patient management. However, there are large variations in biomarker measurements among and within laboratories. Methods Data from the first nine rounds of the Alzheimer's Association quality control program was used to define the extent and sources of analytical variability. In each round, three CSF samples prepared at the Clinical Neurochemistry Laboratory (Mölndal, Sweden) were analyzed by single-analyte enzyme-linked immunosorbent assay (ELISA), a multiplexing xMAP assay, or an immunoassay with electrochemoluminescence detection. Results A total of 84 laboratories participated. Coefficients of variation (CVs) between laboratories were around 20% to 30%; within-run CVs, less than 5% to 10%; and longitudinal within-laboratory CVs, 5% to 19%. Interestingly, longitudinal within-laboratory CV differed between biomarkers at individual laboratories, suggesting that a component of it was assay dependent. Variability between kit lots and between laboratories both had a major influence on amyloid beta 1–42 measurements, but for total tau and phosphorylated tau, between-kit lot effects were much less than between-laboratory effects. Despite the measurement variability, the between-laboratory consistency in classification of samples (using prehoc-derived cutoffs for AD) was high (>90% in 15 of 18 samples for ELISA and in 12 of 18 samples for xMAP). Conclusions The overall variability remains too high to allow assignment of universal biomarker cutoff values for a specific intended use. Each laboratory must ensure longitudinal stability in its measurements and use internally qualified cutoff levels. Further standardization of laboratory procedures and improvement of kit performance will likely increase the usefulness of CSF AD biomarkers for researchers and clinicians.
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| 4. |
- Bul, Meelan, et al.
(författare)
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Active Surveillance for Low-Risk Prostate Cancer Worldwide: The PRIAS Study
- 2013
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Ingår i: European Urology. - : Elsevier BV. - 1873-7560 .- 0302-2838. ; 63:4, s. 597-603
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Tidskriftsartikel (refereegranskat)abstract
- Background: Overdiagnosis and subsequent overtreatment are important side effects of screening for, and early detection of, prostate cancer (PCa). Active surveillance (AS) is of growing interest as an alternative to radical treatment of low-risk PCa. Objective: To update our experience in the largest worldwide prospective AS cohort. Design, setting, and participants: Eligible patients had clinical stage T1/T2 PCa, prostate-specific antigen (PSA) <= 10 ng/ml, PSA density <0.2 ng/ml per milliliter, one or two positive biopsy cores, and Gleason score <= 6. PSA was measured every 3-6 mo, and volume-based repeat biopsies were scheduled after 1, 4, and 7 yr. Reclassification was defined as more than two positive cores or Gleason >6 at repeat biopsy. Recommendation for treatment was triggered in case of PSA doubling time <3 yr or reclassification. Outcome measurements and statistical analysis: Multivariate regression analysis was used to evaluate predictors for reclassification at repeat biopsy. Active therapy-free survival (ATFS) was assessed with a Kaplan-Meier analysis, and Cox regression was used to evaluate the association of clinical characteristics with active therapy over time. Results and limitations: In total, 2494 patients were included and followed for a median of 1.6 yr. One or more repeat biopsies were performed in 1480 men, of whom 415 men (28%) showed reclassification. Compliance with the first repeat biopsy was estimated to be 81%. During follow-up, 527 patients (21.1%) underwent active therapy. ATFS at 2 yr was 77.3%. The strongest predictors for reclassification and switching to deferred treatment were the number of positive cores (two cores compared with one core) and PSA density. The disease-specific survival rate was 100%. Follow-up was too short to draw definitive conclusions about the safety of AS. Conclusions: Our short-term data support AS as a feasible strategy to reduce overtreatment. Clinical characteristics and PSA kinetics during follow-up can be used for risk stratification. Strict monitoring is even more essential in men with high-risk features to enable timely recognition of potentially aggressive disease and offer curative intervention. Limitations of using surrogate end points and markers in AS should be recognized.
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| 6. |
- Carlsson, Sigrid V., et al.
(författare)
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Can one blood draw replace transrectal ultrasonography-estimated prostate volume to predict prostate cancer risk?
- 2013
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Ingår i: BJU International. - 1464-4096 .- 1464-410X. ; 112:5, s. 602-609
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Tidskriftsartikel (refereegranskat)abstract
- Objective To explore whether a panel of kallikrein markers in blood: total, free and intact prostate-specific antigen (PSA) and kallikrein-related peptidase 2, could be used as a non-invasive alternative for predicting prostate cancer on biopsy in a screening setting. Subjects and Methods The study cohort comprised previously unscreened men who underwent sextant biopsy owing to elevated PSA (3 ng/mL) in two different centres of the European Randomized Study of Screening for Prostate Cancer, Rotterdam (n = 2914) and Gteborg (n = 740). A statistical model, based on kallikrein markers, was compared with one based on established clinical factors for the prediction of biopsy outcome. Results The clinical tests were found to be no better than blood markers, with an area under the curve in favour of the blood measurements of 0.766 vs. 0.763 in Rotterdam and 0.809 vs. 0.774 in Gteborg. Adding digital rectal examination (DRE) or DRE plus transrectal ultrasonography (TRUS) volume to the markers improved discrimination, although the increases were small. Results were similar for predicting high-grade cancer. There was a strong correlation between the blood measurements and TRUS-estimated prostate volume (Spearman's correlation 0.60 in Rotterdam and 0.57 in Gteborg). Conclusions In previously unscreened men, each with indication for biopsy, a statistical model based on kallikrein levels was similar to a clinical model in predicting prostate cancer in a screening setting, outside the day-to-day clinical practice. Whether a clinical approach can be replaced by laboratory analyses or used in combination with decision models (nomograms) is a clinical judgment that may vary from clinician to clinician depending on how they weigh the different advantages and disadvantages (harms, costs, time, invasiveness) of both approaches.
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| 7. |
- Gupta, A., et al.
(författare)
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A four-kallikrein panel for the prediction of repeat prostate biopsy: data from the European Randomized Study of Prostate Cancer Screening in Rotterdam, Netherlands
- 2010
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Ingår i: British Journal of Cancer. - : Springer Science and Business Media LLC. - 1532-1827 .- 0007-0920. ; 103:5, s. 708-714
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Most men with elevated levels of prostate-specific antigen (PSA) do not have prostate cancer, leading to a large number of unnecessary biopsies. A statistical model based on a panel of four kallikreins has been shown to predict the outcome of a first prostate biopsy. In this study, we apply the model to an independent data set of men with previous negative biopsy but persistently elevated PSA. METHODS: The study cohort consisted of 925 men with a previous negative prostate biopsy and elevated PSA (>= 3 ngml(-1)), with 110 prostate cancers detected (12%). A previously published statistical model was applied, with recalibration to reflect the lower positive biopsy rates on rebiopsy. RESULTS: The full-kallikrein panel had higher discriminative accuracy than PSA and DRE alone, with area under the curve (AUC) improving from 0.58 (95% confidence interval (CI): 0.52, 0.64) to 0.68 (95% CI: 0.62, 0.74), P<0.001, and high-grade cancer (Gleason >= 7) at biopsy with AUC improving from 0.76 (95% CI: 0.64, 0.89) to 0.87 (95% CI: 0.81, 0.94), P 0.003). Application of the panel to 1000 men with persistently elevated PSA after initial negative biopsy, at a 15% risk threshold would reduce the number of biopsies by 712; would miss (or delay) the diagnosis of 53 cancers, of which only 3 would be Gleason 7 and the rest Gleason 6 or less. CONCLUSIONS: Our data constitute an external validation of a previously published model. The four-kallikrein panel predicts the result of repeat prostate biopsy in men with elevated PSA while dramatically decreasing unnecessary biopsies. British Journal of Cancer (2010) 103, 708-714. doi:10.1038/sj.bjc.6605815 www.bjcancer.com Published online 27 July 2010 (C) 2010 Cancer Research UK
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- Johannsdottir, Inga M. R., et al.
(författare)
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Increased prevalence of chronic fatigue among survivors of childhood cancers: A population-based study
- 2012
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Ingår i: Pediatric Blood & Cancer. - : Wiley. - 1545-5017 .- 1545-5009. ; 58:3, s. 415-420
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Tidskriftsartikel (refereegranskat)abstract
- Background Fatigue is prevalent in adult cancer survivors but less studied in childhood cancer survivors. Aims were to assess fatigue levels, prevalence of chronic fatigue (CF) and the association of CF with health-related quality of life (HRQoL) in survivors of acute myeloid leukemia (AML), infratentorial astrocytoma (IA), and Wilms tumor (WT) in childhood.
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| 10. |
- Johannsdottir, Inga M. R., et al.
(författare)
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Social outcomes in young adult survivors of low incidence childhood cancers
- 2010
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Ingår i: Journal of Cancer Survivorship. - : Springer Science and Business Media LLC. - 1932-2267 .- 1932-2259. ; 4:2, s. 110-118
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Tidskriftsartikel (refereegranskat)abstract
- Introduction The intensity and duration of childhood cancer treatment may disrupt psychosocial development and thereby cause difficulties in transition into adulthood. The study objective was to assess social outcomes in early adulthood after successful treatment for childhood acute myeloid leukemia (AML), Wilms tumor (WT) and infratentorial astrocytoma (IA). Methods Nordic patients treated for AML, WT and IA from 1985 to 2001 identified from a database administered by NOPHO (Nordic Society of Paediatric Haematology and Oncology) were invited to participate in a postal survey. All cancer-free survivors treated at age > 1 year who were > 19 years at time of study were eligible. Seventy-four percent; 247/335 responded. An age-equivalent group (N= 1,814) from a Norwegian Census Study served as controls. Results Mean age of survivors was 23 years (range 1934), 55% females. The proportion with academic education (>= 4 years) was similar in survivors and controls (28 vs. 32%). Fifty-nine percent of survivors were employed compared to 77% among controls (p <. 01). More survivors were recipients of social benefits (6.7 vs. 3.1%, p <. 01). There were no differences in marital status but parenthood was more common among controls (37 vs. 27%, p=. 01). Controls lived longer in their parental homes (p=. 01). Cancer type or treatment intensity had no statistically significant impact on results, except for parenthood. Conclusions and Implications for Cancer Survivors The study revealed important differences in social outcomes between survivors and controls early in adult life. Specific difficulties pertain to studying social status in early adulthood because of the natural transition characteristics for this age group. Therefore, longer follow-up is warranted.
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