1,721,009 research outputs found
Re: Mark K. Buyyounouski. Radiobiological modeling and the study of hypofractionated radiotherapy for prostate cancer. Eur Urol 2014;66:1031-2
No full textPostoperative radiotherapy in prostate cancer: acquired certainties and still open issues. A review of recent literature
No full textIt is recognized that radiation therapy can eradicate microscopic tumor disease, even in postoperative prostate cancer patients, when extracapsular extension, positive surgical margins or increased prostate-specific antigen is found in surgical specimens. This review of recent literature analyzes and discusses acquired certainties and still open questions regarding type, timing, doses, techniques, toxicities, and associated hormonal therapies of radiotherapy prescribed after radical prostatectomy
Reply to Berardino de Bari, Filippo Alongi, Stefano Arcangeli's Letter to the Editor re: Cesare Cozzarini, Claudio Fiorino, Chiara Deantoni, et al. Higher-than-expected Severe (Grade 3-4) late urinary toxicity after postprostatectomy hypofractionated radiotherapy: A single-institution analysis of 1176 patients. Eur Urol 2014;66:1024-30
No full textModelling the impact of fractionation on late urinary toxicity after postprostatectomy radiation therapy
No full textPurpose To fit urinary toxicity data of patients treated with postprostatectomy radiation therapy with the linear quadratic (LQ) model with/without introducing a time factor.Methods and Materials Between 1993 and 2010, 1176 patients were treated with conventional fractionation (1.8 Gy per fraction, median 70.2 Gy, n=929) or hypofractionation (2.35-2.90 Gy per fraction, n=247). Data referred to 2004-2010 (when all schemes were in use, n=563; conventional fractionation: 316; hypofractionation: 247) were fitted as a logit function of biological equivalent dose (BED), according to the LQ model with/without including a time factor Î3 (fixing α/Î2 = 5 Gy). The 3-year risks of severe urethral stenosis, incontinence, and hematuria were considered as endpoints. Best-fit parameters were derived, and the resulting BEDs were taken in multivariable backward logistic models, including relevant clinical variables, considering the whole population.Results The 3-year incidences of severe stenosis, incontinence, and hematuria were, respectively, 6.6%, 4.8%, and 3.3% in the group treated in 2004-2010. The best-fitted α/Î2 values were 0.81 Gy and 0.74 Gy for incontinence and hematuria, respectively, with the classic LQ formula. When fixing α/Î2 = 5 Gy, best-fit values for Î3 were, respectively, 0.66 Gy/d and 0.85 Gy/d. Sensitivity analyses showed reasonable values for Î3 (0.6-1.0 Gy/d), with comparable goodness of fit for α/Î2 values between 3.5 and 6.5 Gy. Likelihood ratio tests showed that the fits with/without including Î3 were equivalent. The resulting multivariable backward logistic models in the whole population included BED, pT4, and use of antihypertensives (area under the curve [AUC] = 0.72) for incontinence and BED, pT4, and year of surgery (AUC = 0.80) for hematuria. Stenosis data could not be fitted: a 4-variable model including only clinical factors (acute urinary toxicity, pT4, year of surgery, and use of antihypertensives) was suggested (AUC = 0.73).Conclusions The unexpected impact of moderate hypofractionation on severe incontinence and hematuria after postprostatectomy radiation therapy may be explained by a bladder α/Î2 value <1 Gy or, radiobiologically more plausible, by introducing a time factor likely to represent a previously hypothesized consequential component of late effect
Dose escalation in salvage radiation therapy and urinary toxicity: A small price to pay for a significant prospective benefit
No full text
Salvage Radiation Therapy for Increasing Prostate-Specific Antigen After Radical Prostatectomy: Who, When, and How?
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
