62 research outputs found

    Parenchymal preserving anatomic resections result in less pulmonary function loss in patients with Stage I non-small cell lung cancer

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    Background: A suggested benefit of sublobar resection for stage I non-small cell lung cancer (NSCLC) compared to lobectomy is a relative preservation of pulmonary function. Very little objective data exist, however, supporting this supposition. We sought to evaluate the relative impact of both anatomic segmental and lobar resection on pulmonary function in patients with resected clinical stage I NSCLC. Methods: The records of 159 disease-free patients who underwent anatomic segmentectomy (n = 89) and lobectomy (n = 70) for the treatment of stage I NSCLC with pre- and postoperative pulmonary function tests performed between 6 to 36 months after resection were retrospectively reviewed. Changes in forced expiratory volume in one second (FEV1) and diffusion capacity of carbon monoxide (DLCO) were analyzed based upon the number of anatomic pulmonary segments removed: 1-2 segments (n = 77) or 3-5 segments (n = 82). Results: Preoperative pulmonary function was worse in the lesser resection cohort (1-2 segments) compared to the greater resection group (3-5 segments) (FEV1(%predicted): 79% vs. 85%, p = 0.038; DLCO(%predicted): 63% vs. 73%, p = 0.010). A greater decline in FEV1 was noted in patients undergoing resection of 3-5 segments (FEV1 (observed): 0.1 L vs. 0.3 L, p = 0.003; and FEV1 (% predicted): 4.3% vs. 8.2%, p = 0.055). Changes in DLCO followed this same trend (DLCO(observed): 1.3 vs. 2.4 mL/min/mmHg, p = 0.015; and DLCO(% predicted): 3.6% vs. 5.9%, p = 0.280). Conclusions: Parenchymal-sparing resections resulted in better preservation of pulmonary function at a median of one year, suggesting a long-term functional benefit with small anatomic segmental resections (1-2 segments). Prospective studies to evaluate measurable functional changes, as well as quality of life, between segmentectomy and lobectomy with a larger patient cohort appear justified

    Pretreatment SUV<inf>max</inf> predicts progression-free survival in early-stage non-small cell lung cancer treated with stereotactic body radiation therapy

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    Background: This retrospective study aims to assess the usefulness of SUVmax from FDG-PET imaging as a prognosticator for primary biopsy-proven stage I NSCLC treated with SBRT.Methods: This study includes 95 patients of median age 77 years, with primary, biopsy-confirmed peripheral stage IA/IB NSCLC. All patients were treated with 60Gy in 3 fractions with a median treatment time of six days. Local, regional, and distant failures were evaluated independently according to the terms of RTOG1021. Local, regional, and distant control, overall- and progression-free survival were estimated by the Kaplan-Meier method. Cox proportional hazards regression was performed to determine whether SUVmax, age, KPS, gender, tumor size/T stage, or smoking history influenced outcomes. SUVmax was evaluated as both a continuous and as a dichotomous variable using a cutoff of <5 and ≥5.Results: Median follow-up for the cohort was 16 months. Median OS and PFS were 25.3 and 40.3 months, respectively. SUV with a cutoff value of 5 predicted for OS and PFS (p = .024 for each) but did not achieve significance for LC (p = .256). On Cox univariate regression analysis, SUV as a dichotomous variable predicted for both OS and PFS (p = .027 and p = .030, respectively). Defined as a continuous variable, SUVmax continued to predict for OS and PFS (p = .032 and p = .003), but also predicted LC (p = .045) and trended toward significance for DC (p = .059).SUVmax did not predict for OS as a dichotomous or continuous variable. It did, however, predict for PFS as a continuous variable (p = .008), neared significance for local control (p = .057) and trended towards, significance for distant control (p = .092).Conclusions: SUVmax appears to be a statistically and clinically significant independent prognostic marker for progression-free survival in patients with stage I NSCLC treated with SBRT. Prospective studies to more accurately define the role of tumor FDG uptake in the prognosis of NSCLC are warranted. © 2014 Horne et al.; licensee BioMed Central Ltd

    Using the net benefit regression framework to construct cost-effectiveness acceptability curves: an example using data from a trial of external loop recorders versus Holter monitoring for ambulatory monitoring of "community acquired" syncope

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    BACKGROUND: Cost-effectiveness acceptability curves (CEACs) describe the probability that a new treatment or intervention is cost-effective. The net benefit regression framework (NBRF) allows cost-effectiveness analysis to be done in a simple regression framework. The objective of the paper is to illustrate how net benefit regression can be used to construct a CEAC. METHODS: One hundred patients referred for ambulatory monitoring with syncope or presyncope were randomized to a one-month external loop recorder (n = 49) or 48-hour Holter monitor (n = 51). The primary endpoint was symptom-rhythm correlation during monitoring. Direct costs were calculated based on the 2003 Ontario Health Insurance Plan (OHIP) fee schedule combined with hospital case costing of labour, materials, service and overhead costs for diagnostic testing and related equipment. RESULTS: In the loop recorder group, 63.27% of patients (31/49) had symptom recurrence and successful activation, compared to 23.53% in the Holter group (12/51). The cost in US dollars for loop recording was 648.50and648.50 and 212.92 for Holter monitoring. The incremental cost-effectiveness ratio (ICER) of the loop recorder was $1,096 per extra successful diagnosis. The probability that the loop recorder was cost-effective compared to the Holter monitor was estimated using net benefit regression and plotted on a CEAC. In a sensitivity analysis, bootstrapping was used to examine the effect of distributional assumptions. CONCLUSION: The NBRF is straightforward to use and interpret. The resulting uncertainty surrounding the regression coefficient relates to the CEAC. When the link from the regression's p-value to the probability of cost-effectiveness is tentative, bootstrapping may be used

    Meiotic Recombination Hotspots of Fission Yeast Are Directed to Loci that Express Non-Coding RNA

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    Polyadenylated, mRNA-like transcripts with no coding potential are abundant in eukaryotes, but the functions of these long non-coding RNAs (ncRNAs) are enigmatic. In meiosis, Rec12 (Spo11) catalyzes the formation of dsDNA breaks (DSBs) that initiate homologous recombination. Most meiotic recombination is positioned at hotspots, but knowledge of the mechanisms is nebulous. In the fission yeast genome DSBs are located within 194 prominent peaks separated on average by 65-kbp intervals of DNA that are largely free of DSBs.). Furthermore, we tested and rejected the hypothesis that the ncRNA loci and DSB peaks localize preferentially, but independently, to a third entity on the chromosomes.Meiotic DSB hotspots are directed to loci that express polyadenylated ncRNAs. This reveals an unexpected, possibly unitary mechanism for what directs meiotic recombination to hotspots. It also reveals a likely biological function for enigmatic ncRNAs. We propose specific mechanisms by which ncRNA molecules, or some aspect of RNA metabolism associated with ncRNA loci, help to position recombination protein complexes at DSB hotspots within chromosomes
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