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December 7, 2006


Delaying colonoscopy to remove mid-sized polyps may be unwise, study suggests

According to a Pitt-led study published in the December issue of Gastroenterology, medium-sized polyps found in the colon with flexible sigmoidoscopy and subsequently evaluated by full colonoscopy are associated with a significant number of advanced adenomas (high-risk pre-cancerous polyps) and cancers. (Flexible sigmoidoscopy examines only a portion of the colon, whereas colonoscopy examines the entire colon.)

The findings raise questions about taking a “wait and watch” approach to medium-sized polyps and delaying referral to colonoscopy, a strategy that could become more popular with newer observational screening tests such as virtual colonoscopy that do not remove polyps.

The study included 10,850 men and women enrolled in the Prostate, Lung, Colorectal and Ovarian Cancer (PLCO) Screening Trial. Participants had an abnormal flexible sigmoidoscopy with at least one detectable polyp and subsequently underwent a diagnostic colonoscopy within one year.

“An emerging issue in colorectal cancer screening is the management of medium-sized polyps, since many new technologies under development can only observe the lining of the colon, and do not offer the ability to remove polyps,” said Robert Schoen, lead author of the study and professor of medicine and epidemiology.

“With these new methods, colonoscopy and polyp removal are required as second procedures, but because of issues of expense and risk, determining a specific threshold for subsequent procedures becomes an important issue. One area of uncertainty concerns medium-sized polyps. In our study, individuals with medium-sized polyps 0.6-0.9 cm were found to have a significant yield of advanced adenomas and even cancer, making an observational strategy in this setting potentially risky.”

In the study, colonoscopies found 14.5 percent of women and 15.9 percent of men were diagnosed with advanced adenomas and 0.6 percent of the women and 0.7 percent of the men were diagnosed with cancer.

“The implication of our study is that where we draw the line when assessing and evaluating polyp size and referral to colonoscopy has to be carefully considered,” said Schoen. “These results offer a cautionary note to waiting and watching.”

Joel L. Weissfeld, assistant professor of epidemiology, was among the co-authors of the study.


Oxygen treatment trial for lung disease funded

The largest National Institutes of Health (NIH)-funded clinical trial of the safety and effectiveness of long-term, home oxygen supplementation for people with moderate severity of chronic obstructive pulmonary disease (COPD) will include investigators from Pitt’s Division of Pulmonary, Allergy and Critical Care Medicine as well as scientists and clinicians from 13 other major medical institutions nationwide. The six-year, $28 million Long-Term Oxygen Treatment Trial is being funded through the National Heart, Lung and Blood Institute, a component of NIH, in partnership with the Centers for Medicare & Medicaid Services.

Oxygen therapy is currently proven to reduce disabling symptoms and prolong survival only in patients with very low oxygen levels while resting.

Frank Sciurba, principal investigator of the Pittsburgh team and associate professor of medicine at the School of Medicine, said, “As appealing as the idea is that home oxygen therapy could benefit greater numbers of patients, deeper study is necessary to determine the risks and benefits first. By using supplemental oxygen earlier in the disease process, we may be able to improve function, exercise tolerance and maybe even survival for people with this disease.”

COPD, a lung disease commonly related to smoking, diminishes breathing capacity over time and includes conditions such as chronic bronchitis and emphysema. Symptoms include a recurring cough, wheezing, shortness of breath, overproduction of sputum and inability to breathe deeply.

Charles W. Atwood Jr., associate professor of medicine at the School of Medicine and a co-investigator for the Pittsburgh team, added, “COPD damages the lung tissue, expanding and breaking down the walls of air sacs, which hinders air flow into the lungs and transfer of oxygen into the blood. This study will help patients and their health providers decide whether use of home oxygen treatment is beneficial for them.”

Sciurba said, “With our aging population, we expect to see increasing numbers of patients with COPD, especially in the Pittsburgh area since our smoking rates — some 25 percent — are higher than elsewhere in the United States. Already, COPD is responsible for 120,000 deaths a year. We are working every day to increase awareness of the disease and find new ways to help our patients.”


Study to look into causes of prematurity

A recent study from the U.S. Centers for Disease Control and Prevention found that pre-term birth contributed to more than one-third of infant deaths — twice as many as previously thought, making it the leading cause of infant deaths. Still, the underlying causes of premature birth are not well understood. A new investigation by researchers at Magee-Womens Research Institute (MWRI) is the first to address the interactions of genetic and environmental factors such as nutrition and inflammation that may figure in the racial disparity in preterm birth, or birth prior to 37 weeks gestation.

More than a half-million babies are born too soon each year, and the preterm birth rate has increased more than 30 percent since 1981. Babies who do survive may face risks of lifelong challenges related to cerebral palsy, mental retardation, chronic lung disease, or vision and hearing loss, as well as other developmental problems.

“Preterm birth is a complex condition, and this in-depth study of nutritional status and genetics is unique,” said Hyagriv Simhan, assistant professor of obstetrics, gynecology and reproductive sciences at the School of Medicine and principal investigator for the study.

The five-year, $2.8 million study funded by the National Institute of Child Health and Human Development will enroll 1,200 participants early in pregnancy to discern the interrelationship of dietary factors, genetics and infection-related inflammatory changes in the lower genital tract that are known to predispose women to preterm birth.

The study aims to determine whether poor nutrition before conception and during pregnancy is associated with an increased risk for preterm birth, how nutritional status affects the risk of genital tract inflammation and the roles of genetic mutations and race, which may predispose women to infection.

“We know, for instance, that African-American women are much more likely than white women to have genetic mutations that are associated with infection-related preterm birth,” said Simhan, who also is an assistant investigator at MWRI and director of the Prematurity Center at Magee-Womens Hospital.

Study participants will be asked to provide investigators with information about their diet, body-mass indices and weight gains during pregnancy. In addition, blood and nail samples will be analyzed for an objective reflection of nutritional status.

Simhan speculates white women may have a more nutrient-rich diet. Compared with white women during pregnancy, African-American women report higher intakes of calories, fat and vitamin C, while white women consume increased amounts of protein, folate and fiber. African-American women are more likely than white women to have third-trimester anemia (42 percent compared to 24 percent) and iron deficiency (15 percent versus 10 percent).

During their childbearing years, some 42 percent of African-American women suffer vitamin D deficiency, compared with 4 percent of white women. They also are more likely than whites to gain inadequate weight during pregnancy, Simhan said.

“Understanding the influence of environment and gene-environment interactions on inflammation is critical to understanding the racial disparity in preterm birth,” said Simhan.

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