Johnie Rose

American Cancer Society Colorectal Cancer Survivorship Care Guidelines.

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Public health impact and cost effectiveness of mass vaccination with live attenuated human rotavirus vaccine (RIX4414) in India: model based analysis.

Objectives To examine the public health impact of mass vaccination with live attenuated human rotavirus vaccine (RIX4414) in a birth cohort in India, and to estimate the cost effectiveness and affordability of such a programme. Design Decision analytical Markov model encompassing all direct medical costs. Infection risk and severity depended on age, number of previous infections, and vaccination history; probabilities of use of inpatient and outpatient health services depended on symptom severity. Data sources Published clinical, epidemiological, and economic data. When possible, parameter estimates were based on data specific for India. Population Simulated Indian birth cohort followed for five years. Main outcome measures Decrease in rotavirus gastroenteritis episodes (non-severe and severe), deaths, outpatient visits, and admission to hospital; incremental cost effectiveness ratio of vaccination expressed as net cost in 2007 rupees per life year saved. Results In the base case, vaccination prevented 28 943 (29.7%) symptomatic episodes, 6981 (38.2%) severe episodes, 164 deaths (41.0%), 7178 (33.3%) outpatient visits, and 812 (34.3%) admissions to hospital per 100 000 children. Vaccination cost 8023 rupees (about £100, €113,

Metastatic spread pattern after curative colorectal cancer surgery. A retrospective, longitudinal analysis.

165) per life year saved, less than India’s per capita gross domestic product, a common criterion for cost effectiveness. The net programme cost would be equivalent to 11.6% of the 2006-7 budget of the Indian Department of Health and Family Welfare. Model results were most sensitive to variations in access to outpatient care for those with severe symptoms. If this parameter was increased to its upper limit, the incremental cost effectiveness ratio for vaccination still fell between one and three times the per capita gross domestic product, meeting the World Health Organization’s criterion for “cost effective” interventions. Uncertainty analysis indicated a 94.7% probability that vaccination would be cost effective according to a criterion of one times per capita gross domestic product per life year saved, and a 97.8% probability that it would be cost effective according to a criterion of three times per capita gross domestic product. Conclusions Across a wide range of assumptions, mass RIX4414 vaccination in India would probably prevent substantial morbidity and mortality at a cost per life year saved below typical thresholds of cost effectiveness. The opportunity costs of such a programme in this or similar settings, however, should be weighed up carefully.

Colorectal cancer surveillance:What’s new and what’s next?

OBJECTIVE The most common sites of colorectal cancer (CRC) recurrence are the local tissues, liver or lungs. The objective was to identify risk factors associated with the primary CRC tumor and cancer recurrence in these anatomical sites. METHODS Retrospective, longitudinal analyses of data on CRC survivors. Multivariable Cox regression analysis was performed to examine the association between possible cofounders with recurrence to various anatomical sites. RESULTS Data for 10,398CRC survivors (tumor location right colon=3870, left colon=2898, high rectum=2569, low rectum=1061) were analyzed; follow up time was up to five years. Mean age at curative surgery was 71.5 (SD 11.8) years, 20.2% received radio-chemotherapy, stage T3 (64.4%) and N0 (65.1%) were most common. Overall 1632 (15.7%) had cancer recurrence (Isolated liver n=412, 3,8%;  isolated lung n=252, 2,4%; isolated local n=223, 2.1%). Risk factors associated with recurrent CRC were identified, i.e. isolated liver metastases (male: Adjusted Hazard Ratio (AHR) 1,45; colon left: AHR 1,63; N2 disease: AHR 3,35; T2 disease: AHR 2,82), isolated lung metastases (colon left: AHR 1,53; rectum high: AHR 2,48; rectum low: AHR 2,65; N2 disease 3,76), and local recurrence (glands examined<12: AHR 1,51; CRM <3mm: AHR 1,60; rectum high: AHR 2,15; N2 disease: AHR 2,58) (all p values <0001). CONCLUSION Our study finds that the site of the primary CRC tumor is associated with location of subsequent metastasis. Left sided colon cancers have increased risk of metastatic spread to the liver, whereas rectal cancers have increased risk of local recurrence and metastatic spread to the lungs. These results, in combination with other risk factors for CRC recurrence, should be taken into consideration when designing risk adapted post-treatment CRC surveillance programs.

A Participatory Model of the Paradox of Primary Care

The accumulated evidence from two decades of randomized controlled trials has not yet resolved the question of how best to monitor colorectal cancer (CRC) survivors for early detection of recurrent and metachronous disease or even whether doing so has its intended effect. A new wave of trial data in the coming years and an evolving knowledge of relevant biomarkers may bring us closer to understanding what surveillance strategies are most effective for a given subset of patients. To best apply these insights, a number of important research questions need to be addressed, and new decision making tools must be developed. In this review, we summarize available randomized controlled trial evidence comparing alternative surveillance testing strategies, describe ongoing trials in the area, and compare professional society recommendations for surveillance. In addition, we discuss innovations relevant to CRC surveillance and outline a research agenda which will inform a more risk-stratified and personalized approach to follow-up.

Projecting Vaccine Efficacy: Accounting for Geographic Strain Variations

PURPOSE The paradox of primary care is the observation that primary care is associated with apparently low levels of evidence-based care for individual diseases, but systems based on primary care have healthier populations, use fewer resources, and have less health inequality. The purpose of this article is to explore, from a complex systems perspective, mechanisms that might account for the effects of primary care beyond disease-specific care. METHODS In an 8-session, participatory group model-building process, patient, caregiver, and primary care clinician community stakeholders worked with academic investigators to develop and refine an agent-based computer simulation model to test hypotheses about mechanisms by which features of primary care could affect health and health equity. RESULTS In the resulting model, patients are at risk for acute illness, acute life-changing illness, chronic illness, and mental illness. Patients have changeable health behaviors and care-seeking tendencies that relate to their living in advantaged or disadvantaged neighborhoods. There are 2 types of care available to patients: primary and specialty. Primary care in the model is less effective than specialty care in treating single diseases, but it has the ability to treat multiple diseases at once. Primary care also can provide disease prevention visits, help patients improve their health behaviors, refer to specialty care, and develop relationships with patients that cause them to lower their threshold for seeking care. In a model run with primary care features turned off, primary care patients have poorer health. In a model run with all primary care features turned on, their conjoint effect leads to better population health for patients who seek primary care, with the primary care effect being particularly pronounced for patients who are disadvantaged and patients with multiple chronic conditions. Primary care leads to more total health care visits that are due to more disease prevention visits, but there are reduced illness visits among people in disadvantaged neighborhoods. Supplemental appendices provide a working version of the model and worksheets that allow readers to run their own experiments that vary model parameters. CONCLUSION This simulation model provides insights into possible mechanisms for the paradox of primary care and shows how participatory group model building can be used to evaluate hypotheses about the behavior of such complex systems as primary health care and population health.

Do the benefits outweigh the side effects of colorectal cancer surveillance? A systematic review

Researchers must often make assumptions about the efficacy of an intervention in a target population without the benefit of trial data specific to that population. Such assumptions may be particularly tenuous with models of vaccination strategies, since the distribution of pathogen strains in target populations may differ substantially from the strain distributions in trial sites. We describe a technique for projecting expected vaccine efficacy in settings where applying unadjusted trial-based efficacy data may overestimate the benefits of immunization. This simple method uses data describing setting-specific strain distributions of pathogens and strain-specific vaccine efficacies to generate a weighted overall efficacy. An example of estimating the expected efficacy of a new rotavirus vaccine in India is used to illustrate the technique. The method is shown to perform very well in a validation population for whom actual efficacy had been observed and can therefore aid those in the international health community in determining the optimal uses of scarce resources.

A simulation model of colorectal cancer surveillance and recurrence

Most patients treated with curative intent for colorectal cancer (CRC) are included in a follow-up program involving periodic evaluations. The survival benefits of a follow-up program are well delineated, and previous meta-analyses have suggested an overall survival improvement of 5%-10% by intensive follow-up. However, in a recent randomized trial, there was no survival benefit when a minimal vs an intensive follow-up program was compared. Less is known about the potential side effects of follow-up. Well-known side effects of preventive programs are those of somatic complications caused by testing, negative psychological consequences of follow-up itself, and the downstream impact of false positive or false negative tests. Accordingly, the potential survival benefits of CRC follow-up must be weighed against these potential negatives. The present review compares the benefits and side effects of CRC follow-up, and we propose future areas for research.

Modeling the Paradox of Primary Care

BackgroundApproximately one-third of those treated curatively for colorectal cancer (CRC) will experience recurrence. No evidence-based consensus exists on how best to follow patients after initial treatment to detect asymptomatic recurrence. Here, a new approach for simulating surveillance and recurrence among CRC survivors is outlined, and development and calibration of a simple model applying this approach is described. The model’s ability to predict outcomes for a group of patients under a specified surveillance strategy is validated.MethodsWe developed an individual-based simulation model consisting of two interacting submodels: a continuous-time disease-progression submodel overlain by a discrete-time Markov submodel of surveillance and re-treatment. In the former, some patients develops recurrent disease which probabilistically progresses from detectability to unresectability, and which may produce early symptoms leading to detection independent of surveillance testing. In the latter submodel, patients undergo user-specified surveillance testing regimens. Parameters describing disease progression were preliminarily estimated through calibration to match five-year disease-free survival, overall survival at years 1–5, and proportion of recurring patients undergoing curative salvage surgery from one arm of a published randomized trial. The calibrated model was validated by examining its ability to predict these same outcomes for patients in a different arm of the same trial undergoing less aggressive surveillance.ResultsCalibrated parameter values were consistent with generally observed recurrence patterns. Sensitivity analysis suggested probability of curative salvage surgery was most influenced by sensitivity of carcinoembryonic antigen assay and of clinical interview/examination (i.e. scheduled provider visits). In validation, the model accurately predicted overall survival (59% predicted, 58% observed) and five-year disease-free survival (55% predicted, 53% observed), but was less accurate in predicting curative salvage surgery (10% predicted; 6% observed).ConclusionsInitial validation suggests the feasibility of this approach to modeling alternative surveillance regimens among CRC survivors. Further calibration to individual-level patient data could yield a model useful for predicting outcomes of specific surveillance strategies for risk-based subgroups or for individuals. This approach could be applied toward developing novel, tailored strategies for further clinical study. It has the potential to produce insights which will promote more effective surveillance—leading to higher cure rates for recurrent CRC.

Boundary Objects for Participatory Group Model Building of Agent-Based Models

A paradox exists in the outcomes of primary care: despite delivering apparently poorer quality disease care compared to that delivered by specialists, primary care is associated with better population health, lower inequality, and lower cost. Understanding the dynamics that give rise to this paradox could lead to better-informed interventions to promote more patient-centered, holistic, equitable, and cost-effective models of care. In this chapter, we articulate the paradox and how complexity science principles can make sense of its contradictions. We suggest a novel approach to advancing understanding through a participatory group modeling process to build and conduct experiments with an agent-based computational model.