Estimating Treatment-Switching Bias in a Randomized Clinical Trial of Ovarian Cancer Treatment: Combining Causal Inference with Decision-Analytic Modeling.

BACKGROUND: Bevacizumab is efficacious in delaying ovarian cancer progression and controlling ascites. The ICON7 trial showed a significant benefit in overall survival for bevacizumab, whereas the GOG-218 trial did not. GOG-218 allowed control group patients to switch to bevacizumab upon progression, which may have biased the results. Lack of data on switching behavior prevented the application of g-methods to adjust for switching. The objective of this study was to apply decision-analytic modeling to estimate the impact of switching bias on causal treatment-effect estimates. METHODS: We developed a causal decision-analytic Markov model (CDAMM) to emulate the GOG-218 trial and estimate overall survival. CDAMM input parameters were based on data from randomized clinical trials and the published literature. Overall switching proportion was based on GOG-218 trial information, whereas the proportion switching with and without ascites was estimated using calibration. We estimated the counterfactual treatment effect that would have been observed had no switching occurred by denying switching in the CDAMM. RESULTS: The survival curves generated by the CDAMM matched well with the ones reported in the GOG-218 trial. The survival curve correcting for switching showed an estimated bias such that 79% of the true treatment effect could not be observed in the GOG-218 trial. Results were most sensitive to changes in the proportion progressing with severe ascites and mortality. LIMITATIONS: We used a simplified model structure and based model parameters on published data and assumptions. Robustness of the CDAMM was tested and model assumptions transparently reported. CONCLUSIONS: Medical-decision science methods may be merged with empirical methods of causal inference to integrate data from other sources where empirical data are not sufficient. We recommend collecting sufficient information on switching behavior when switching cannot be avoided.

Standard chemotherapy with or without bevacizumab in advanced ovarian cancer: quality-of-life outcomes from the International Collaboration on Ovarian Neoplasms (ICON7) phase 3 randomised trial.

BACKGROUND: In the Gynecologic Cancer Intergroup International Collaboration on Ovarian Neoplasms 7 (ICON7) trial, bevacizumab improved progression-free survival in patients with ovarian cancer when used in combination with first-line chemotherapy and as a single-drug continuation treatment for 18 cycles. In a preliminary analysis of a high-risk subset of patients, there was also an improvement in overall survival. This study aims to describe the health-related quality-of-life (QoL) outcomes from ICON7. METHODS: ICON7 is a randomised, multicentre, open-label phase 3 trial. Between Dec 18, 2006, and Feb 16, 2009, after a surgical procedure aiming to debulk the disease, women with International Federation of Gynecology and Obstetrics (FIGO) high-risk stage I-IV epithelial ovarian cancer were randomly allocated (1:1) by computer program and block randomisation to receive either six cycles of standard chemotherapy (total 18 weeks) with carboplatin (area under the curve 5 or 6) and paclitaxel (175 mg/m(2)) alone or with bevacizumab (7·5 mg/kg) given intravenously with chemotherapy and continued as a single drug thereafter (total 54 weeks). The primary QoL endpoint was global QoL from the European Organisation for Research and Treatment of Cancer quality-of-life questionnaire-core 30 at week 54, analysed by ANOVA and adjusted for baseline score. Analyses were by intention to treat. The ICON7 trial has completed recruitment and remains in follow-up. This study is registered, number ISRCTN91273375. FINDINGS: 764 women were randomly assigned to the standard chemotherapy group and 764 to the bevacizumab group. At baseline, 684 (90%) of women in the standard chemotherapy group and 691 (90%) of those in the bevacizumab group had completed QoL questionnaires. At week 54, 502 (66%) women in the bevacizumab group and 388 (51%) women in the standard chemotherapy group provided QoL data. Overall, the mean global QoL score improved during chemotherapy by 7·2 points (SD 24·4) when analysed for all women with data at baseline and week 18. The mean global QoL score at 54 weeks was higher in the standard chemotherapy group than in the bevacizumab group (76·1 [SD 18·2] vs 69·7 [19·1] points; difference 6·4 points, 95% CI 3·7-9·0, p<0·0001). INTERPRETATION: Bevacizumab continuation treatment seems to be associated with a small but clinically significant decrement in QoL compared with standard treatment for women with ovarian cancer. The trade-off between the prolongation of progression-free survival and the quality of that period of time needs to be considered in clinical practice when making treatment decisions. FUNDING: Roche and the National Institute for Health Research through the UK National Cancer Research Network.

Adherence to heroin dependence therapies and human immunodeficiency virus/acquired immunodeficiency syndrome infection rates among drug abusers.

Adherence is a primary determinant of treatment effectiveness; thus, poor adherence attenuates optimum clinical benefit. A bibliographic review was conducted to evaluate the impact of adherence to heroin dependence treatment on human immunodeficiency virus (HIV) transmission and to identify interventions proven to be effective in improving adherence. The best adherence rates were achieved by methadone and diacetylmorphine, both of which are comparable in promoting significant reduction in heroin use. Methadone adjusted-dose studies with daily doses ranging from 100 to 200 mg and multiple support interventions achieved the highest adherence rates. Studies of methadone maintenance that examined changes in HIV prevalence of infection have found that higher treatment adherence is correlated with a reduction in HIV transmission. These data suggest that patients who adhere continuously to methadone treatment are less likely to continue injecting illicit drugs and sharing contaminated injection equipment than are those who interrupt treatment, thus preventing the spread of HIV via drug injection.

Pseudo-aneurismas traumáticos / Traumatic pseudoaneurism

Realizamos una revisión retrospectiva de 18 casos de pacientes que acudieron a la emergencia de Cirugía del Hospital Miguel Perez Carreño durante el quinquenio 85-90 y que presentaron traumatismo en las extremidades, con lesión subclínica de trayectos vasculares, recibiendo sólo tratamiento médico, presentando posteriormente la formación de pseudoaneurismas. El agente vulnerante más usado fue el arma de fuego. La región anatómica más lesionada fue el muslo, siendo el vaso más frecuentemente afectado la Arteria Femoral superficial. El diagnóstico se hizo en la mayoría de los casos por la clínica. Es de considerar que aun cuando no hay evidencia clínica de lesión debe realizarse una exploración quirúrgica en un primer tiempo ya que en caso de encontrarse lesión arterial la misma sera reparada, evitando la formación de un pseudoaneurisma