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Risk-stratified imputation in survival analysis
Kennedy, Richard , Adragni, Kofi P. , Tiwari, Hemant K., Voeks, Jenifer H. , Brott, Thomas G. , Howard, George , Kennedy, Richard E , Howard, George

Clinical Trials | July 2, 2013 | Volume: 10 | Issue: 4 | Pages: 530-539

10.1177/1740774513493150 | PMID 23818434 Get It

Background Censoring that is dependent on covariates associated with survival can arise in randomized trials due to changes in recruitment and eligibility criteria to minimize withdrawals, potentially leading to biased treatment effect estimates. Imputation approaches have been proposed to address censoring in survival analysis; while these approaches may provide unbiased estimates of treatment effects, imputation of a large number of outcomes may over- or underestimate the associated variance based on the imputation pool selected. Purpose We propose an improved method, risk-stratified imputation, as an alternative to address withdrawal related to the risk of events in the context of time-to-event analyses. Methods Our algorithm performs imputation from a pool of replacement subjects with similar values of both treatment and covariate(s) of interest, that is, from a risk-stratified sample. This stratification prior to imputation addresses the requirement of time-to-event analysis that censored observations are representative of all other observations in the risk group with similar exposure variables. We compared our risk-stratified imputation to case deletion and bootstrap imputation in a simulated dataset in which the covariate of interest (study withdrawal) was related to treatment. A motivating example from a recent clinical trial is also presented to demonstrate the utility of our method. Results In our simulations, risk-stratified imputation gives estimates of treatment effect comparable to bootstrap and auxiliary variable imputation while avoiding inaccuracies of the latter two in estimating the associated variance. Similar results were obtained in analysis of clinical trial data. Limitations Risk-stratified imputation has little advantage over other imputation methods when covariates of interest are not related to treatment. Risk-stratified imputation is intended for categorical covariates and may be sensitive to the width of the matching window if continuous covariates are used. Conclusions The use of the risk-stratified imputation should facilitate the analysis of many clinical trials, in which one group has a higher withdrawal rate that is related to treatment.
Longitudinal Changes in Left Ventricular Stiffness
Redfield, Margaret M. , Melenovský, Vojtěch , Kane, Garvan C. , Karon, Barry L., Jacobsen, Steven J. , Rodeheffer, Richard J. , Borlaug, Barry A. , Melenovský, Vojtěch

Circulation: Heart Failure | June 29, 2013 | Volume: 6 | Issue: 5 | Pages: 944-952

10.1161/circheartfailure.113.000383 | PMID 23811963 Get It

Background— Cross-sectional studies suggest that left ventricular (LV) and arterial elastance (stiffness) increase with age, but data examining longitudinal changes within human subjects are lacking. In addition, it remains unknown whether age-related LV stiffening is merely a reaction to arterial stiffening or caused by other processes. Methods and Results— Comprehensive echo-Doppler cardiography was performed in 1402 subjects participating in a randomly selected community-based study at 2 examinations separated by 4 years. From this population, 788 subjects had adequate paired data to determine LV end-systolic elastance (Ees), end-diastolic elastance (Eed), and effective arterial elastance. Throughout 4 years, blood pressure, arterial elastance, and LV mass decreased, coupled with significantly greater use of antihypertensive medications. However, despite reductions in arterial load, Ees increased by 14% (2.10±0.67–2.26±0.70 mm Hg/mL; P <0.0001) and Eed increased by 8% (0.13±0.03–0.14±0.04 mm Hg/mL; P <0.0001). Increases in Eed were greater in women than men, whereas Ees changes were similar. Age-related increases in Ees and Eed were correlated with changes in body weight, but were similar in subjects with or without cardiovascular disease. Changes in Ees were correlated with Eed ( r =0.5; P <0.0001), but not with other measures of contractility, indicating that the increase in Ees was reflective of passive stiffening rather than enhanced systolic function. Conclusions— Despite reductions in arterial load with medical therapy, LV systolic and diastolic stiffness increase over time in humans, particularly in women. In addition to blood pressure control, therapies targeting load-independent ventricular stiffening may be effective to treat and prevent age-associated cardiovascular diseases, such as heart failure.
Nitrofurantoin-Induced Granulomatous Interstitial Pneumonia
Sakata, Kenneth K. , Larsen, Brandon T. , Boland, Jennifer M. , Palen, Brian N., Muhm, John R., Helmers, Richard A. , Tazelaar, Henry D. , Palen, Brian, Tazelaar, Henry D.

International Journal of Surgical Pathology | June 28, 2013 | Volume: 22 | Issue: 4 | Pages: 352-357

10.1177/1066896913492849 | PMID 23812013 Get It

Nitrofurantoin-induced lung toxicity is relatively common, but rare histologic patterns sometimes occur that may make diagnosis difficult. We present the case of a 69-year-old woman taking prophylactic nitrofurantoin for urinary tract infections, who developed granulomatous interstitial pneumonia. She improved with cessation of nitrofurantoin, without other therapy. To our knowledge, this is the fourth reported case of granulomatous interstitial pneumonia associated with nitrofurantoin, and the first to show complete resolution with cessation of the drug alone, without steroids. It is important to recognize that idiosyncratic reactions to nitrofurantoin can produce a wide spectrum of histologic patterns. Of these patterns, granulomatous interstitial pneumonia is a rarely evidenced manifestation (possibly because few cases undergo a confirmatory lung biopsy). Recognition of granulomatous interstitial pneumonia as a manifestation of nitrofurantoin toxicity can aid in early identification of the reaction and prompt withdrawal of the drug, both of which are essential to prevent long-term complications.
MR elastography derived shear stiffness-a new imaging biomarker for the assessment of early tumor response to chemotherapy
Pepin, Kay , Glaser, Kevin J. , Mariappan, Yogesh K. , Reuland, Brian, Ziesmer, Steven C., Carter, Rickey E. , Ansell, Stephen M. , McGee, Kiaran P. , Chen, Jun , Ehman, Richard L. , Carter, Rickey E , Mariappan, Yogesh Kannan

Magnetic Resonance in Medicine | June 25, 2013 | Volume: 71 | Issue: 5 | Pages: 1834-1840

10.1002/mrm.24825 | PMID 23801372 Get It

Consensus statement on the multidisciplinary management of patients with recurrent and primary rectal cancer beyond total mesorectal excision planes
Collaborative, The Beyond TME, Antoniou, Anthony , Beynon, John, Bhangu, Aneel , Bose, Pradeep, Boyle, Kirsten, Branagan, Graham , Burling, David , Chang, George J. , Clark, Susan K. , Colquhoun, Patrick, Crane, Christopher H. , Darzi, Ara , Das, Prajnan , Delaney, Conor P. , Desai, Anant, Davies, Mark, Dozois, Eric J. , Fitzgerald, J.E.F. , Frizelle, Frank , George, Bruce , George, Mark, Georgiou, Panagiotis , Gupta, Arun , Harris, Dean , Hawkins, M. , Holm, Torbjörn, Hompes, Roel , Jeys, Lee , Jenkins, John T. , Kiran, Ravi P. , Koh, Cherry , Laurberg, Søren , Law, Wai Lun, Liberman, A. Sender , McArthur, D. Ray, Mirnezami, Alex H. , Moran, Brendan , Mortenson, Neil, Myers, Eddie, Nicholls, R. John, O’Connell, P. R. , O’Dwyer, Sarah , Oliver, Alex, Pallan, Arvind, Patel, Prashant , Patel, Uday , Radley, Simon, Ramsey, Kelvin , Rasmussen, P., Richard, Carole, Rutten, H.J.T. , Sagar, P. M. , Sebag‐Montefiore, David , Stocchi, Luca , Swallow, Carol J. , Tait, Diana , Tan, Emile , Tekkis, Paris, As, Nicholas van , Vuong, T. , Wiggers, Theo , Wilson, Malcolm , Winter, Desmond C. , Woodhouse, Christopher, Collaborative, The Beyond TME, Ali, Simak , Brown, Gina , Wilt, Johannes H.W. de , Desai, Anant , Dietz, David , Duff, Michael J. B. , Dziki, Adam Janusz , Glynne‐Jones, Rob , Goldin, Robert , Harji, Deena Pravin , Heriot, Alexander G. , Marshall, Michelle Berger , Radley, Simon, Solomon, Michael J. , Jeys, Lee M

British Journal of Surgery | June 21, 2013 | Volume: 100 | Issue: 8 | Pages: E1-E33

10.1002/bjs.9192_1 | PMID 23901427 Get It

Consensus abstract Background The management of primary rectal cancer beyond total mesorectal excision planes (PRC-bTME) and recurrent rectal cancer (RRC) is challenging. There is global variation in standards and no guidelines exist. To achieve cure most patients require extended, multivisceral, exenterative surgery, beyond conventional total mesorectal excision planes. The aim of the Beyond TME Group was to achieve consensus on the definitions and principles of management, and to identify areas of research priority. Methods Delphi methodology was used to achieve consensus. The Group consisted of invited experts from surgery, radiology, oncology and pathology. The process included two international dedicated discussion conferences, formal feedback, three rounds of editing and two rounds of anonymized web-based voting. Consensus was achieved with more than 80 per cent agreement; less than 80 per cent agreement indicated low consensus. During conferences held in September 2011 and March 2012, open discussion took place on areas in which there is a low level of consensus. Results The final consensus document included 51 voted statements, making recommendations on ten key areas of PRC-bTME and RRC. Consensus agreement was achieved on the recommendations of 49 statements, with 34 achieving consensus in over 95 per cent. The lowest level of consensus obtained was 76 per cent. There was clear identification of the need for referral to a specialist multidisciplinary team for diagnosis, assessment and further management. Conclusion The consensus process has provided guidance for the management of patients with PRC-bTME or RRC, taking into account global variations in surgical techniques and technology. It has further identified areas of research priority.
Hybrid submental flaps for reconstruction in the head and neck: Part pedicled, part free
Hayden, Richard E. , Nagel, Thomas H. , Donald, Carrlene B.

The Laryngoscope | June 17, 2013 | Volume: 124 | Issue: 3 | Pages: 637-641

10.1002/lary.24266 | PMID 23775702 Get It

Objectives/Hypothesis Evaluate feasibility and success of elongating only the venous pedicle of the submental flap to increase the superior arc of rotation for the “hybrid” flap allowing coverage of more distal defects. Study Design Retrospective evaluation of all submental flaps undergoing pedicle‐lengthening procedure at a single institution. Methods Medical records were reviewed for all patients undergoing reconstruction with submental flaps between 2002 and 2012. Information regarding demographics, etiology, location, size, and extent of defects, type of submental flap harvested, operative time, and outcomes were recorded. Special note was made of vascular pedicle length and any pedicle vessel manipulation to increase the superior arc of rotation. Results Nine patients (67% male) with a mean age of 61 years (range, 25–83 years) underwent hybrid submental flap procedures. Eight surgical defects resulted from cancer ablation and one from trauma. Five flaps were musculocutaneous, and four were osseomusculocutaneous. The divided pedicle vein was anastomosed to the external jugular vein (n = 6), retromandibular vein (n = 1), common facial vein (n = 1), and internal jugular vein (n = 1). Pedicle vessel elongation averaged 5 cm. Skin paddle size averaged 71 cm 2 (range, 48–99 cm 2 ). All donor sites were closed primarily with no further surgery required. One flap experienced venous thrombosis and was successfully salvaged. Overall flap survival was 100%. No local or regional cancer recurrence was detected in the cancer patients with a mean follow‐up of 20 months (range, 3–87 months). Conclusions The hybrid submental flap safely extends the arc of rotation 5 cm, allowing coverage of defects in the forehead, temporal‐parietal, and occipital regions. Level of Evidence 4. Laryngoscope , 124:637–641, 2014
Selective Estrogen Receptor Modulators and Pharmacogenomic Variation in ZNF423 Regulation of BRCA1 Expression: Individualized Breast Cancer Prevention
Liu, Mohan , Wickerham, D. Lawrence, Schaid, Daniel J. , Wang, Liewei , Kubo, Michiaki , Costantino, Joseph P., Vogel, Victor G. , Paik, Soonmyung , Ames, Matthew M. , Jenkins, Gregory D. , Batzler, Anthony , Flockhart, David A., Nakamura, Yusuke , Weinshilboum, Richard M. , Ingle, James N. , Mushiroda, Taisei , Goetz, Matthew P. , Carlson, Erin E. , Wolmark, Norman , Weinshilboum, Richard M.

Cancer Discovery | June 14, 2013 | Volume: 3 | Issue: 7 | Pages: 812-825

10.1158/2159-8290.cd-13-0038 | PMID 23764426 Get It

Abstract The selective estrogen receptor modulators (SERM) tamoxifen and raloxifene can reduce the occurrence of breast cancer in high-risk women by 50%, but this U.S. Food and Drug Administration-approved prevention therapy is not often used. We attempted to identify genetic factors that contribute to variation in SERM breast cancer prevention, using DNA from the NSABP P-1 and P-2 breast cancer prevention trials. An initial discovery genome-wide association study identified common single-nucleotide polymorphisms (SNP) in or near the ZNF423 and CTSO genes that were associated with breast cancer risk during SERM therapy. We then showed that both ZNF423 and CTSO participated in the estrogen-dependent induction of BRCA1 expression, in both cases with SNP-dependent variation in induction. ZNF423 appeared to be an estrogen-inducible BRCA1 transcription factor. The OR for differences in breast cancer risk during SERM therapy for subjects homozygous for both protective or both risk alleles for ZNF423 and CTSO was 5.71. Significance: This study identified novel, functionally polymorphic genes involved in the estrogen-dependent regulation of BRCA1 expression, as well as a novel mechanism for genetic variation in SERM therapeutic effect. These observations, and definition of their underlying mechanisms, represent steps toward pharmacogenomically individualized SERM breast cancer prevention. Cancer Discov; 3(7); 812–25. ©2013 AACR. See related commentary by Machiela and Chanock, p. 728 This article is highlighted in the In This Issue feature, p. 705
Consensus statement on the multidisciplinary management of patients with recurrent and primary rectal cancer beyond total mesorectal excision planes
Collaborative, The Beyond TME, Antoniou, Anthony , Beynon, John, Bose, Pradeep, Boyle, Kirsten, Branagan, Graham , Brown, Gina , Burling, David , Chang, George J. , Clark, Susan K. , Colquhoun, Patrick, Crane, Christopher H. , Darzi, Ara , Das, Prajnan , Wilt, Johannes H. W. de, Delaney, Conor P. , Desai, Anant, Davies, Mark, Dozois, Eric J. , Fitzgerald, J.E.F. , Frizelle, Frank , George, Bruce , George, Mark, Georgiou, Panagiotis , Glynne‐Jones, R., Goldin, Robert , Gupta, Arun , Harris, Dean , Hawkins, M. , Holm, Torbjörn, Jenkins, John T. , Kiran, Ravi P. , Laurberg, Søren , Law, Wai Lun, Liberman, A. Sender , McArthur, D. Ray, Mirnezami, Alex H. , Moran, Brendan , Mortenson, Neil, Myers, Eddie, Nicholls, R. John, O’Connell, P. R. , O’Dwyer, Sarah , Oliver, Alex, Pallan, Arvind, Patel, Prashant , Radley, Simon, Ramsey, Kelvin , Rasmussen, P., Richard, Carole, Rutten, H.J.T. , Sagar, P. M. , Sebag‐Montefiore, David , Solomon, Michael J. , Stocchi, Luca , Swallow, Carol J. , Tait, Diana , Tekkis, Paris, As, Nicholas van , Vuong, T. , Wiggers, Theo , Wilson, Malcolm , Winter, Desmond C. , Woodhouse, Christopher, Coombes, R. Charles , Collaborative, The Beyond TME, Ali, Simak , Bhangu, Aneel , Desai, Anant , Dietz, David , Duff, Michael J. B. , Dziki, Adam Janusz , Harji, Deena Pravin , Heriot, Alexander G. , Hompes, Roel , Jeys, Lee , Koh, Cherry , Marshall, Michelle Berger , Patel, Uday , Radley, Simon, Tan, Emile , Solomon, Michael J

British Journal of Surgery | June 10, 2013 | Volume: 100 | Issue: 8 | Pages: 1009-1014

10.1002/bjs.9192 | PMID 23754654 Get It

Consensus abstract Background The management of primary rectal cancer beyond total mesorectal excision planes (PRC-bTME) and recurrent rectal cancer (RRC) is challenging. There is global variation in standards and no guidelines exist. To achieve cure most patients require extended, multivisceral, exenterative surgery, beyond conventional total mesorectal excision planes. The aim of the Beyond TME Group was to achieve consensus on the definitions and principles of management, and to identify areas of research priority. Methods Delphi methodology was used to achieve consensus. The Group consisted of invited experts from surgery, radiology, oncology and pathology. The process included two international dedicated discussion conferences, formal feedback, three rounds of editing and two rounds of anonymized web-based voting. Consensus was achieved with more than 80 per cent agreement; less than 80 per cent agreement indicated low consensus. During conferences held in September 2011 and March 2012, open discussion took place on areas in which there is a low level of consensus. Results The final consensus document included 51 voted statements, making recommendations on ten key areas of PRC-bTME and RRC. Consensus agreement was achieved on the recommendations of 49 statements, with 34 achieving consensus in over 95 per cent. The lowest level of consensus obtained was 76 per cent. There was clear identification of the need for referral to a specialist multidisciplinary team for diagnosis, assessment and further management. Conclusion The consensus process has provided guidance for the management of patients with PRC-bTME or RRC, taking into account global variations in surgical techniques and technology. It has further identified areas of research priority.
Inflammatory hypertrophic cauda equina following intrathecal neural stem cell injection
Hurst, Richard W., Bosch, E. Peter, Dyck, P. James B. , Reeves, Ronald K. , Morris, Jonathan M.

Muscle & Nerve | June 6, 2013 | Volume: 48 | Issue: 5 | Pages: 831-835

10.1002/mus.23920 | PMID 23740462 Get It