terça-feira, 30 de setembro de 2014
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Increase Brainpower by Walking
Mehmet C. Oz, MD, and Michael F. Roizen, MD
Forgetting things? Can't remember where you put that dang whatchamacallit? Listen up. We have something for you that can do what no drug on the market can: improve your memory and even ward off Alzheimer's. It won't cost you a dime. Ready?
Walk out the door. (Wait! Finish reading this first.)
Yep, it's that simple. Put one foot in front of the other for 30 minutes a day and you'll cut your risk of memory loss and Alzheimer's disease, the ultimate memory thief, by 50%, according to a study. Even if you already have early signs of cognitive decline or Alzheimer's, walking 5 miles a week could put the skids on that.
So how does a walk around the block turn aging brain cells into whiz kids?
Strolling makes your brain bigger. And with this organ, size does matter. Increased blood flow to your neurons from even mild aerobic activity prevents the brain shrinkage that occurs with age and accelerates with Alzheimer's. Walking sends fresh oxygen and blood straight to the parts of the brain that keep you witty and clever enough to actually remember a punch line.
Boosting brainpower isn't the only benefit. Walking perks up your mood, adds energy, cuts your chances of diabetes, and sparks your sex life (keeping blood flowing to that other organ where size may or may not matter). Even slow walkers have fewer heart attacks and strokes than couch potatoes do.
Need inspiration? Take a walk down memory lane.
Age Benefits
Walking at least 20 minutes a day can make your RealAge as much as 1.9 years younger if you're a woman and 1.2 years younger if you're a man.
February, 2011
segunda-feira, 29 de setembro de 2014
O tamanho do pré-sal
Cristovam Buarque
20 de Setembro de 2014 às 09:10
Não usar a riqueza do pré-sal seria uma estupidez, usá-la para iludir a nação é uma indecência
Não usar a riqueza do pré-sal seria uma estupidez, usá-la para iludir a nação é uma indecência. As estimativas para as reservas do pré-sal podem não ser exatas, mas não são mitos, são resultados de pesquisas geológicas; a exploração na sua profundidade não é um mito, a engenharia dispõe de ferramentas; a crença de que pode ser feita sem riscos para a ecologia não é um mito, embora haja exemplos de vazamentos em campos similares; a expectativa de que a demanda e os preços continuarão altos não é um mito, apesar das novas fontes.
Mito, contudo, é a afirmação de que o pré-sal mudará a realidade brasileira.
Se tudo der certo, em 2036 a receita líquida prevista do setor petrolífero corresponderá a R$ 100 bilhões, aproximadamente R$ 448 por brasileiro, quando a renda per capita será de R$ 27.800, estimando crescimento de 2% ao ano para o PIB. Apesar da dimensão da sua riqueza, o pré-sal não terá o impacto que o governo tenta passar. Explorá-lo é correto, concentrar sua receita na educação é ainda mais correto, mas é indecente usar o pré-sal como uma ilusão para enganar a nação e como mecanismo para justificar o adiamento de investimentos em educação.
O Brasil não cabe dentro de um poço de petróleo, nem deve esperar por ele.
Mito também é a afirmação de que a educação brasileira será universalizada e dará um salto de qualidade graças ao pré-sal. Em 2030, uma educação de qualidade universal custará cerca de R$ 511 bilhões, para o custo/aluno/ano de R$ 9.500. Se tudo der certo, a totalidade dos recursos do setor petrolífero destinada à educação corresponderá a R$ 37 bilhões, apenas 7,2% do necessário.
Também é um mito dizer que o atual governo teve a iniciativa da proposta de investir 75% dos royalties do petróleo em educação. A partir do momento da descoberta do pré-sal, 44 projetos de lei foram apresentados na Câmara e no Senado.
Mas foi com a aprovação do substitutivo PLC 41/2013 ao PL 323/2007, do deputado Brizola Neto, em 14/8/2013, após parecer favorável do deputado André Figueiredo (PDT-CE), que se determinou o destino de 100% dos royalties para a educação e a saúde. As atas mostram que os líderes da base de apoio ao governo tentaram impedir a aprovação, mas foram derrotados no voto.
Além de não serem destinados à educação os R$ 15 bilhões dos Bônus de Assinatura do Leilão do Campo de Libra, os recursos dos royalties não estão sendo aplicados. Até 28 de agosto, um ano depois da sanção da lei, apenas R$ 912 milhões foram efetivamente transferidos para o Ministério da Educação, ou seja, somente 13,5% do valor de R$ 4,2 bilhões previsto pela Lei de Diretrizes Orçamentárias para 2014.
Enquanto o mundo vive uma revolução no conhecimento, estamos ficando para trás, eufóricos com a promessa de mudar nossa triste realidade educacional no futuro distante, com base em um recurso ainda na profundidade de sete mil metros e que não será suficiente. E o pouco prometido não está sendo cumprido.
World needs ‘paradigm shift’ towards sustainable agriculture, UN agency urges
Photo: World Bank/Maria Fleischmann
29 September 2014 – In order to move towards more sustainable agriculture, a broader approach is needed to overhaul the world’s food system, the head of the United Nations Food and Agriculture Organization (FAO) said today, as he pressed for a global reduction in the quantity of chemicals and water in contemporary agriculture.
Speaking at the opening of the 24th session of the Committee on Agriculture (COAG) in Rome, Director-General José Graziano da Silva called for a “paradigm shift” in global attitudes on agriculture, adding that only by decreasing the amounts of “inputs,” such as water and chemicals, could the sector move towards a more sustainable and productive long-term path.
“We cannot rely on an input-intensive model to increase production,” Mr. Graziano da Silva declared. “The solutions of the past have shown their limits.”
Pointing to options such as agro-ecology, climate-smart agriculture, biotechnology and the use of genetically modified organisms, the Director-General emphasized that global food production would need to grow by 60 per cent by 2050 in order to meet the expected demand from an anticipated world population of nine billion.
“We need to explore these alternatives using an inclusive approach based on science and evidence, not on ideologies,” he continued.
Established in 1971 and with over 100 members within its ranks, the COAG’s biennial meeting is currently addressing a wide range of issues, including family farming, sustainable agriculture, food safety, water governance, soil management and agricultural heritage systems.
Addressing the Committee in his keynote speech, the President of the Dominican Republic, Danilo Medina, underscored his Government’s support of the principle that food be considered a universal right and noted that his country was on the verge of passing a law establishing said right.
News Tracker: past stories on this issue
World hunger falls, but number of undernourished remains ‘unacceptably high’ – joint UN report
In-flight sensor tests a step toward structural health monitoring for safer flights
"The flight test program is underway," said Dennis Roach, a senior scientist in Sandia National Laboratories' Transportation, Safeguards & Surety Program who has worked in aviation safety for 25 years. "We have moved past laboratory research and are looking for certification for actual on-board usage. Our activities are proving that the sensors work on particular applications and that it is safe and reliable to use these sensor systems for routine aircraft maintenance."
Delta Air Lines Inc. and a foreign aircraft manufacturer have partnered with Sandia researchers in two separate programs to install about 100 sensors on their commercial aircraft. These teams worked together to provide the installation procedures for technicians and now oversee monitoring of the in-flight tests.
The flight tests complement laboratory performance testing at Sandia to provide the critical step in a decade-long journey to enhance airline safety through a more comprehensive program of Structural Health Monitoring. SHM uses nondestructive inspection principles -- technologies that examine materials for damage without affecting their usefulness -- and built-in sensors that automatically and remotely assess an aircraft's structural condition in real time and signal the need for maintenance.
Roach said the goal of monitoring the sensors installed on the aircraft is to accumulate successful flight history to show that the sensors can sustain the operating environment, while providing the proper signals for flaw detection.
SHM eventually could help airlines save money by basing maintenance on the actual condition of the aircraft, rather than fixed schedules and inspection routines that might not be necessary, and thereby reduce airplanes' downtimes, Roach said.
The team said so far, sensors installed on the aircraft are working as expected.
Next year, Sandia intends to present the flight and laboratory test results to the FAA for approval and certification. Should the FAA approve the sensors, they would be available for specific applications across the entire airline industry and the process for certifying future applications should be more efficient because of the research being conducted now.
Two SHM systems reach maturity for use on regular flights
Sandia began its work in aviation safety in 1991 when the FAA, in response to a number of aviation incidents, increased its research efforts to improve inspection, maintenance and repair of commercial aircraft. Among the projects to improve aviation safety, the FAA created the AANC, operated by Sandia, to conduct research into nondestructive inspection (NDI), advanced materials, engines, structural integrity and a wide range of other airworthiness assurance areas.
The center provides a way to develop, evaluate and bring new aircraft technologies to the airline industry, Roach said. "We work to make the technology viable and often focus on that last phase of technology validation and certification."
The current SHM program is testing two sensors: Comparative Vacuum Monitoring (CVM) sensors manufactured by Structural Monitoring Systems and piezoelectric sensor arrays produced by Sunnyvale, Calif.-based Acellent Technologies Inc.
- CVM sensors improve crack detection by monitoring "galleries," or 0.025-inch channels etched by laser into the Teflon sensor. CVM sensors are then mounted in areas of the aircraft known to experience fatigue. The sensors are bonded to the surface of the structure with an adhesive surface preparation that seals out the atmosphere, creating a vacuum inside the gallery. When a tiny crack intersects the gallery, the pressure changes, much like the pressure in a vacuum cleaner changes when the hose has a leak. The sensor records the pressure change and alerts inspectors well before the crack becomes a safety issue.
- Piezoelectric sensors (PZT) are strategically distributed in polyimide films -- called Acellent's SMART Layers -- that adhere to an airplane's surface to monitor specific regions for damage. The array of PZT sensors communicate with one another by transmitting and receiving ultrasonic surface waves called Lamb waves. This creates a mini-communications network. Damage to the aircraft disrupts or changes the signal patterns from the baseline communication signals. Acellent's software measures and analyzes any changes, called the "damage index," and sends an alert to the inspector. Work is ongoing on the best spacing and placement for these sensors on aircraft, Sandia mechanical engineer Stephen Neidigk said.
Both of these on-board sensors must meet the same performance and reliability standards as those required for current maintenance inspections, Roach said. "The SHM systems also help eliminate some of the concerns about human factors associated with manually-deployed NDI," he said. "You have the sensor in place, you know it works and it's giving you a proper signal, whereas an inspector must manually orient the inspection probe properly each time and there are always concerns about human vigilance when inspections become time-consuming or tedious."
The sensors are custom built to fit an aircraft's parts, they are verified to be working before they are sealed inside the aircraft and the readouts provide inspectors with a "pass" or "fail" decision so the results can't be misinterpreted, the researchers said.
Sandia also is researching wide-area monitoring using piezoelectric and fiber optic strain sensors for composite materials used in today's aircraft. Impacts don't always show dents in composite materials, so SHM techniques are needed to find structural damage within what appears to be a smooth, undamaged surface, Neidigk said.
Field tests bridge gap from lab to routine use in aircraft
The field tests have helped fine tune the sensors, so they can withstand the harsh environments aircraft fly in and the environment aircraft mechanics work in, neither of which is as pristine as the laboratories where the sensors were initially tested.
For example, field testing showed that mechanics working in the cramped bowels of an aircraft couldn't see well enough to connect the sensors' tubes together by hand, Neidigk said. So the team designed snap-clip type connectors for the CVM sensors, like those used to plug a telephone landline into a wall outlet.
"With the snap-click connectors, they are able to feel them click together, which is easier than the previous method of connecting tiny tubes individually by hand," Neidigk said.
Growing realistic cracks part of Sandia performance tests
Complementing the in-flight tests, Sandia is looking at the sensors' ability to detect cracks and how well they perform in extreme environmental conditions.
In the laboratory, Sandia engineer Tom Rice breaks things for a living, but that's not as easy as it sounds. The cracks he "grows" have to represent cracks found on an airplane. So, for example, he places a pale green wing box fitting on a load frame that mimics the stress conditions the part would experience on an aircraft. After about four hours of accelerated fatigue cycles, a crack begins to show.
"We literally have to grow the crack enough to where it stays open (without the load on it), so our sensors can detect the crack when the aircraft is in an unloaded state in the maintenance hangar," Rice explained.
Once the sensors detect an array of cracks, Sandia assembles various test scenarios and collects the data to calculate the statistical probability of detection for cracks of various lengths, typically fractions of inches.
In hundreds of laboratory tests, the sensors have never issued a false call, Rice said.
Future of SHM can reduce costs, enhance safety for airline industry
If flight tests verify that the sensors can be used to help monitor airliners' structural health, the Sandia researchers hope to see a more comprehensive SHM program follow.
In addition to safety enhancement, SHM would save the airline industry time and money, particularly if sensors are mounted in hard-to-reach areas and used widely throughout an aircraft, Roach said.
With today's routine maintenance, inspectors often need to remove a cabin's interior seats or galleys to conduct inspections. But with the on-board sensors mounted in place, the mechanics can plug in from a convenient location to acquire the sensor data without the time and cost of removing items, Roach said. Such part removal also introduces the possibility of damaging the structure during disassembly.
Researchers hope SHM eventually will permit the real-time condition of the aircraft to dictate maintenance. "The ultimate goal is to monitor it in-flight and have it tell you 'I need some attention, I've got a problem here.' So you do condition-based maintenance rather than time-based maintenance," Roach said. "That's downstream a ways, but these are all building blocks working toward that."
Rice adds that with SHM, abnormal problems that show up prior to scheduled maintenance would be detected with real-time sensors. "With condition-based maintenance, you could find damage earlier than normal," he said. "It's rare that it happens, but it could."
Such early damage detection and repairs provided by SHM also are cost-effective because they reduce the need for subsequent major repairs, Roach said.
Talk therapy_not medication _ best for social anxiety disorder, large study finds
While antidepressants are the most commonly used treatment for social anxiety disorder, new research suggests that cognitive behavioral therapy (CBT) is more effective and, unlike medication, can have lasting effects long after treatment has stopped.
Social anxiety disorder is a psychiatric condition characterized by intense fear and avoidance of social situations and affects up to 13 percent of Americans and Europeans. Most people never receive treatment for the disorder. For those who do, medication is the more accessible treatment because there is a shortage of trained psychotherapists.
The findings of the study, a network meta-analysis that collected and analyzed data from 101 clinical trials comparing multiple types of medication and talk therapy, are published online Sept. 26 in The Lancet Psychiatry.
"Social anxiety is more than just shyness," says study leader Evan Mayo-Wilson, DPhil, a research scientist in the Department of Epidemiology at the Johns Hopkins Bloomberg School of Public Health. "People with this disorder can experience severe impairment, from shunning friendships to turning down promotions at work that would require increased social interaction. The good news from our study is that social anxiety is treatable. Now that we know what works best, we need to improve access to psychotherapy for those who are suffering."
The research was a collaboration between the Johns Hopkins Bloomberg School of Public Health, Oxford University and University College in London, where Mayo-Wilson formerly worked.
For the study, Mayo-Wilson and his colleagues analyzed data from 13,164 participants in 101 clinical trials. The participants all had severe and longstanding social anxiety. Approximately 9,000 received medication or a placebo pill, and more than 4,000 received a psychological intervention. Few of the trials looked at combining medication with talk therapy, and there was no evidence that combined therapy was better than talk therapy alone.
The data compared several different types of talk therapy and found individual CBT was the most effective. CBT is a form of treatment that focuses on relationships between thoughts, feelings and behaviors. It helps people challenge irrational fears and overcome their avoidance of social situations, Mayo-Wilson says.
For people who don't want talk therapy, or who lack access to CBT, the most commonly used antidepressants -- selective serotonin reuptake inhibitors (SSRIs) -- are effective, the researchers found. But they caution that medication can be associated with serious adverse events, that it doesn't work at all for many people, and that improvements in symptoms do not last after people stop taking the pills.
The researchers acknowledge that medication remains important but say it should be used as a second-line therapy for people who do not respond to or do not want psychological therapy. The group's analysis has already led to new treatment guidelines guidance in the U.K. and, Mayo-Wilson says, it could have a significant impact on policymaking and the organization of care in the U.S.
Social anxiety disorder typically begins in adolescence or early adulthood, and it can severely impair a person's daily functioning by impeding the formation of relationships, by negatively affecting performance at work or school, and by reducing overall quality of life. Because it strikes people at critical times in their social and educational development, social anxiety disorder can have important and lasting consequences.
"Greater investment in psychological therapies would improve quality of life, increase workplace productivity, and reduce healthcare costs," Mayo-Wilson says. "The healthcare system does not treat mental health equitably, but meeting demand isn't simply a matter of getting insurers to pay for psychological services. We need to improve infrastructure to treat mental health problems as the evidence shows they should be treated. We need more programs to train clinicians, more experienced supervisors who can work with new practitioners, more offices, and more support staff."
Story Source:
The above story is based on materials provided by Johns Hopkins Bloomberg School of Public Health. Note: Materials may be edited for content and length.
Journal Reference:
- Evan Mayo-Wilson et al. Psychological and pharmacological interventions for social anxiety disorder in adults: a systematic review and network meta-analysis. The Lancet Psychiatry, September 2014 DOI: 10.1016/S2215-0366(14)70329-3
Chemotherapy: Rolapitant reduces nausea and vomiting in phase III trial
Rolapitant reduces nausea and vomiting in patients receiving cisplatin-based chemotherapy, according to the results of a phase III trial presented for the first time today at the ESMO 2014 Congress in Madrid, Spain.
Dr Martin Chasen, lead author and medical director, Palliative Care, Ottawa Hospital Cancer Centre, Canada, said: "This agent makes a significant difference in the way people tolerate their chemotherapy. Patients experienced no loss in quality of life and, in fact, many saw meaningful improvements. One of the patients in the rolapitant cohort reported that he had just finished 18 holes of golf one week after receiving chemotherapy. This is in sharp contrast to many patients on current standard anti-emetics that are too ill to get out of bed within a week after each cycle of cisplatin."
"We must treat nausea and vomiting, not just the cancer," added Chasen, emphasising that some patients are extremely sensitive to cisplatin effects and recalling that he had one or two patients with curable cancers who refused treatment after one round of cisplatin. "They preferred to die," he said.
The phase III trial investigated rolapitant, a novel antagonist of the NK-1 receptor, for the prevention of severe nausea and vomiting often experienced by patients receiving cisplatin-based chemotherapy, which may cause dose reductions and treatment discontinuation. The multicentre trial randomised 532 patients 1:1 to receive rolapitant plus granisetron/dexamethasone or placebo plus granisetron/dexamethasone prior to cisplatin-based chemotherapy.
The primary endpoint was complete response (defined as the patient having no emesis and not requiring any rescue medication) in the delayed phase (>24-120 hours) post-chemotherapy. Key secondary endpoints included complete response during the acute (0-24 hours) and overall (0-120 hours) phases.
The trial met its primary endpoint, with 72.7% of patients receiving rolapitant achieving complete response in the delayed phase compared to 58.4% of those receiving placebo (p<0.001). Rolapitant also improved the complete response rate compared to placebo in the acute (83.7% vs 73.7%, p=0.005) and overall (70.1% vs 56.5%, p=0.001) phases. Patients receiving rolapitant tended to report that chemotherapy had less of an impact on their daily quality of life (72.8% vs 67.8%, p=0.231).
Chasen said: "Rolapitant demonstrated a significant effect in both the acute and delayed phases. Our primary endpoint was achieved in the delayed phase, an incredible result. We know that the NK-1 receptor in the brain must be blocked to control nausea and vomiting --there are other agents that block this for a short time; rolapitant is an exceptionally long term receptor blocker that binds to the receptor and remains in place for up to 120 hours, therefore not allowing the chemotherapy to induce nausea and vomiting."
The investigators tested the agent in patients receiving cisplatin, possibly the strongest inducer of emesis. "Without a doubt this drug can be evaluated in other less emetogenic cancer treatments," said Chasen.
He pointed out that rolapitant may also save costs. For example, in Ottawa patients can have a visit from a nurse following their chemotherapy who administers intravascular hydration and nutrients. Chasen said: "Patients receiving rolapitant may not require this service. They are able to eat and drink as they should." -END-
Story Source:
The above story is based on materials provided by European Society for Medical Oncology (ESMO). Note: Materials may be edited for content and length.
French studies measure benefits of colorectal cancer screening
Dr Vanessa Cottet from INSERM Unité 866 in Dijon, France, and colleagues studied the region of Côte-d'Or, where a registry has been collecting data on adenomas since 1976. They wanted to evaluate the rate of diagnosis of adenomas before and after the initiation of a screening program using fecal occult blood testing that began in 2003.
The study included all residents aged between 50 and 74 years of age who had a first adenoma identified between January 1997 and December 2008. The researchers showed that 38.7% of these people had high-risk adenomas --meaning they were larger than 1 centimetre in diameter, involved the finger-like projections called villi in the intestinal lining, or exhibited a high grade of dysplasia.
For such high-risk adenomas, age-standardized diagnosis rates were 136 per 100,000 people before screening program and 257 per 100,000 after, which correlates to a percentage increase of 89%. The corresponding rates for non-advanced adenomas were 235 and 392 diagnoses per 100,000, with a percentage increase of 68%.
These results reinforce the value of extending organised mass screening programs for colorectal cancer, the authors say. "It is very important that public follows recommendations and participates in colorectal cancer screening campaigns," Cottet says. "Participation rate is a major issue for the success of such programs."
The authors also found that the rate of detection did not continue increasing between the 2005 and 2007 rounds of screening. However, they suggest that shifting the methodology used in the screening programs from the more common guaiac test to immunochemical testing will improve results in the future.
"Immunochemical fecal occult blood tests outperform guaiac tests for the detection of colorectal cancer and advanced adenoma," Cottet says. "They have doubled the detection rate of invasive colorectal cancer, mostly at early stages, and led to a fourfold increase in the detection rate of non-invasive colorectal cancer and advanced adenomas."
"Given the superior performance of immunochemical tests, it is reasonable to assume that an organized screening program using such tests would led to a greater reduction of colorectal cancer death and probably to a reduction in colorectal cancer incidence."
Caption: Dr Vanessa Cottet and colleagues report that biennial colorectal cancer screening in France's Cote-D'Or region increased detection of high-risk polyps, but that the improvement recently plateaued
Commenting on the study, Professor Hans-Joachim Schmoll, former Head of the Division of Hematology and Oncology and Director of the Center for Cell and Gene Therapy, Martin Luther University, Halle, Germany and Professor of Medicine at Martin Luther University, Germany, said that many retrospective and prospective studies have clearly demonstrated the value of screening for adenoma, polyps and manifest colorectal cancer with respect to early diagnosis and treatment of precursor lesions and manifest tumours, and with regard to improving survival.
"However, the question is which method is most appropriate with respect to accessing the target population, maximising participation in these programs, and efficacy, as well as costs," Schmoll said.
"The French trial reproduces the positive outcome from other studies by looking on the sequential period before and after 2003 when screening programs started in the Côte-d'Or region. They have shown that the stool test for occult blood (guaiac test) was effective by doubling the rate and therefore these data further support the value of screening programs in the general population with a given standard risk, as in this group of people aged 50-75 years."
"It can definitively be expected that the new FOBT-test could have produced even better results," Schmoll said. "Further strong improvement can be expected by the recent new combined test of FOBT together with a molecular test for specific mutations. These third-generation tests are going to be implemented in US and other countries."
However, the optimal method for increasing the detection rate is colonoscopy, or at least sigmoidoscopy, which is implemented as standard in Germany and in the US, at least for a high risk population, Schmoll said. These approaches can be called the 'gold standard', despite several drawbacks including risks from the procedure itself and potential false positive or negative results, he said.
Colonoscopy evaluated in patients at high risk of colorectal cancer For people who have been identified as being at higher risk of developing colorectal cancer, a screening program that uses colonoscopy appears to be less efficient than using fecal occult blood tests, French researchers report.
Dr Sylvain Manfredi from CHU Pontchaillou in Rennes, France, and colleagues conducted their study in a region of the country where fecal occult blood test (FOBT) screening for people with average risk of colorectal cancer has been implemented for long time.
As part of the screening program, a pre-screening procedure is undertaken by a general practitioner or gastroenterologist to identify patients who are at higher than average risk of colorectal cancer based on their family history. Those patients were invited to undergo colonoscopy rather than FOBT.
The aim of the study was to estimate the positive predictive value of colorectal neoplasia in this high-risk group. Positive predictive value is a statistical measure that is defined as the ratio of true positive results to the number of times the test shows a positive result (which can include true positive results and 'false positives' where the test indicates a positive result but the patient does not actually have colorectal cancer).
Of 1179 patients studied, 889 underwent colonoscopy, the researchers report. Overall, 253 colorectal neoplasias were diagnosed including 35 cancers, and adenomas (polyps) in 219 patients. A total of 209 advanced adenomas were diagnosed.
The authors calculated that the positive predictive value of colonoscopy was 3.9% for cancer, 12.9% for advanced adenoma and 25% for adenoma overall.
This compared poorly to the positive predictive value in the average risk population selected by a positive FOBT, they say. In this population, the positive predictive value of the coloscopy done after positive test in their administrative area ranges from 7.5% to 10% for cancer, from 15% to 27% for advanced adenoma and between 32% and 37% for adenoma.
"The take-home message is that the positive predictive value for colorectal neoplasia in high risk patients screened by colonoscopy is lower than it is for average risk patients screened by FOBT."
"As a result, we believe this population may benefit from fecal occult blood or immunochemical blood testing to select the best candidates for colonoscopy." Further studies are required to understand how best this could be achieved, Manfredi said.
"In the study from Manfredi, it was shown that a prediction for screening colonoscopy using high risk features --based on family history-- revealed a less positive predictive value than pre-screening by FOBT with follow-up of those who have a positive result," Schmoll said.
"These data favour the widely used standard approach of routine use of FOBT followed by colonoscopy only when the FOBT test is positive, rather than colonoscopy first. Those patients with prior FOBT are at higher risk for having cancer or precursor lesion compared to those who are only identified by family history," Schmoll said.
"However, if colonoscopy is restricted only to those patients who have positive FOBT, there is a high chance that adenoma or even cancer can be not identified. FOBT can be negative in a number of patients despite the presence of adenoma, precursor lesions or even in early cancer. Therefore the optimal method remains the colonoscopy in all patients," Schmoll said.
"The data support the use of both options as part of a large national screening program which is adapted to several different groups, to optimize the outcome and increase the rate of cure," Schmoll noted.
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