New screening approaches for lung cancer show promise
By Linda Gundersen
Update in pulmonary medicine
When: Saturday, 2:15 a.m. - 3:45 p.m.
Where: Ballroom 20 A
At this year's pulmonary update, moderators Richard A. Helmers, MD, and Michael W. Peterson, FACP, will discuss groundbreaking data on lung cancer screening, as well as the latest studies on asthma, adult respiratory distress syndrome (ARDS), and chronic lung disease.
Lung cancer screening
New imaging techniques using chest CT screening in patients at risk for lung cancer identified a significant proportion of patients-85%-with stage I lung cancer. The patients were identified either at initial or follow-up screening. Subsequent cure rates were significantly improved. The study, published in the New England Journal of Medicine, (355:1763, 2006), is the first to suggest that new screening approaches might benefit patients who are at risk to develop lung cancer.
While screening and outcomes for cancer have generally improved over the years, the mortality rate for lung cancer has seen little change over the last few decades. Standard screening using chest X-ray and sputum psychology has had little impact on cure rates, with lung cancer remaining the leading cause of cancer death in men and women. Typically, patients have been screened after presenting with symptoms, and by that time, they had usually progressed to a higher stage of cancer-with a correlating poor prognosis. "This is one of the first times that we've been able to demonstrate that we can benefit patients with lung cancer using a screening approach," Dr. Peterson said.
Large screening trials to refine parameters for screening high-risk patients are currently underway. According to Dr. Peterson, diagnostic models might ultimately combine screening approaches with genetic factors because there is increasing evidence of the role of genetics in lung cancer.
Dr. Peterson, who is UCSF Fresno chief of medicine and UCSF vice-chair at the department of internal medicine, cautioned that it's too soon to endorse routine screening in every patient over age 45 who smokes. He added, "Certainly, it is something that may be coming in the future." Dr. Peterson and Dr. Helmers, who works in pulmonary disease and critical care medicine at the Mayo Clinic in Arizona, will discuss the impact of this important study at the update.
A study that looked at blocking tumor necrosis factor alpha (TNFa) in patients with refractory asthma showed promising results. As physicians know, some patients' asthma is not well managed with the available arsenal of anti-inflammatory drugs. While refractory asthma has been linked with increased TNFa, the association has not been well examined. This study, published in the New England Journal of Medicine by Berry and colleagues (2006; 354:697-708), showed improved outcomes in patients with refractory asthma who were given etanercept, a TNFa blocker.
Dr. Peterson said the main importance of this study is not that it will change treatment guidelines, but that it will help to change the way the medical community views asthma and its treatment. He explained that asthma has been looked at as a single disease with limited parameters, but clearly, that perception is changing. "There are subgroups of patients, like the one in this study, that are going to need very different approaches," Dr. Peterson said.
A recent study in the New England Journal of Medicine (2006; 354:2213-2224) may be laying to rest an age-old controversy about fluid management in patients with ARDS and acute lung injury. While there was no difference in mortality, patients who had restricted fluids spent less time in the ICU and less time on the mechanical ventilator than those who had standard fluid management.
Physicians have always faced a challenge in managing hemodynamics in these patients, because they develop pulmonary edema. For that reason, some experts have advocated fluid restriction, while others argued that such restriction could result in organ damage, especially of the kidneys. The study showed no significant increase in organ damage in the group with the restricted fluid management. "In fact," Dr. Peterson said, "some organs seem to benefit from the fluid restriction, specifically, the brain."
"This is one of the first times that we've been able to demonstrate that we can benefit patients with lung cancer using a screening approach."
—Michael W. Peterson, FACP
A related study in NEJM (2006; 354:2564-2575) concluded that central venous pressure monitoring was as good as pulmonary artery catheter monitoring and had fewer complications. Monitoring this patient population has proven to be another difficulty for physicians, as controversy has surrounded the use of pulmonary artery catheters in patients in the ICU. According to Dr. Peterson, this is the first time physicians have had evidence supporting less invasive monitoring of these patients.
Chronic lung disease
A study in the American Journal of Respiratory and Critical Care Medicine (2006; 173:744-750) by Leuchte and associates found that elevated brain natriuretic peptide (BNP) can be a useful prognostic indicator for pulmonary hypertension (PH) in patients with chronic lung disease. It is understood that BNP levels become elevated when ventricles are stretched, and that such stretching often occurs with elevated blood pressures in the lungs.
"Physicians can now use elevations of BNP as a prognostic indicator to determine when patients have significant disease and are at much higher risk for death," Dr. Peterson said. The test is a boon to prognosticians, who traditionally rely on echocardiography or heart catheterizations, which are both costly and invasive.
Recent studies have pointed out the benefits of aggressive insulin therapy in surgical ICU patients, but would that approach improve outcomes in medical ICU patients as well? A study by Van den Berghe in the New England Journal of Medicine (2006; 354:449-461) showed that patients in the ICU longer than three days benefited from the aggressive insulin therapy, while patients who were in the ICU less than three days showed no benefit.
Dr. Peterson pointed out, "Unfortunately, we have no good way of predicting who's going to be in the ICU for three days." He advocated a balanced approach. "We're walking a very fine line here. We should try to manage blood sugars a little more aggressively than we have in the past, but not as aggressively as we've done with the surgical ICU population."
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