Diabetes, Heart Disease Can Herald Early GI Cancers

May 2006: Heart disease and diabetes are among the most common conditions plaguing Americans today, and they are related to a host of other diseases. Research presented today at Digestive Disease Week 2006 (DDW) now also demonstrates that these conditions can be warning signs for some types of digestive cancers, and may lead to early screening and interventions that may help prevent the onset of cancer or lead to earlier detection and treatment. Furthermore, certain treatments for these diseases may actually reduce digestive cancer risk. DDW is the largest international gathering of physicians and researchers in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery.

"The presence of diabetes or heart disease can be a signal for clinicians to evaluate patients' risk for digestive cancers," said Randall W. Burt, M.D., professor of medicine, University of Utah School of Medicine and Interim Executive Director, Huntsman Cancer Institute at the University of Utah. "The associations between these two diseases and cancer, as shown in these studies, provide a critical tool to diagnose cancer early when patients might benefit most from treatment. These studies also suggest that certain treatments for heart disease, in particular ACE inhibitors, may reduce the risk of colon, pancreatic and esophageal cancers."

Resectability of Pre-Symptomatic Pancreatic Cancer and its Relationship to Onset of Diabetes: A Retrospective Review of CT Scans and Fasting Glucose Values Prior to Diagnosis [Abstract 952]

Pancreatic cancer is one of the deadliest forms of cancer, claiming the lives of nearly 32,000 people in the United States each year. With few visible symptoms, pancreatic cancer is often difficult to catch early and many patients are not diagnosed until the cancer is too advanced for surgery.

Up to 80 percent of pancreatic cancer patients are diabetic and research now suggests that a recent diagnosis of diabetes may be a marker of early pancreatic cancer. This study looked at CT scans of pancreatic cancer patients who were also diabetic to determine if a new diabetes diagnosis indeed signals early pancreatic cancer, hoping that it would help with asymptomatic detection and a better chance of successful treatment with surgery.

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Mario Pelaez-Luna, M.D., and study partners at the Mayo Clinic in Rochester, Minn. examined the CT scans of 20 patients who had at least one abdominal scan prior to being diagnosed with pancreatic cancer. These initial scans were reviewed to determine the condition of the patient's pancreas no changes, some pancreatic duct narrowing or blockage, early, small tumors, or advanced tumors.

The 20 patients had undergone a total of 23 CT scans six or more months prior to their diagnosis of pancreatic cancer. All scans done more than six months prior to diagnosis showed no definite evidence of cancer. At the time of cancer diagnosis, 80 percent of the cancers were too advanced to be treated with surgery. With regard to the relationship to diabetes, all scans prior to the onset of diabetes were found normal. When patients first showed high blood sugar levels suggestive of diabetes, 85 percent still had a normal-appearing pancreas or showed early cancer; only 15 percent of cancers were advanced. The cancer was diagnosed, on average, five months after the diabetes first developed.

The research suggests that the number of pancreatic cancers amenable to surgical treatment can be greatly increased if the diagnosis is made even six months earlier. Diabetes associated with pancreatic cancer occurs at a time when the tumor is still treatable by surgery. Thus, a new diabetes diagnosis can be a warning sign that pancreatic cancer may be present, leading to an early cancer diagnosis with potentially better outcomes.

"Pancreatic cancer is difficult to treat. By the time patients develop symptoms, the cancer is already at an advanced stage" said Mario Pelaez-Luna, M.D., lead author of the study. "However, discovering new links between pancreatic cancer and other conditions such as diabetes is helping us identify clues to early diagnosis. The only hope of offering surgical treatment to more patients with pancreatic cancer is diagnosing the disease before symptoms develop."

Type 2 Diabetes Mellitus: The Impact on Colorectal Adenoma Risk in Women [Abstract S1245]

Having Type 2 Diabetes Mellitus raises a person's risk for developing colorectal cancer, and while there have been several studies linking insulin resistance to colorectal cancer risk, there is little data on whether women with diabetes are more at risk for colorectal adenomas, or polyps, which can become cancerous.

In this study, researchers from Washington University in St. Louis, MO., selected 600 women undergoing screening colonoscopies 100 had Type 2 (adult onset) diabetes and 500 were non-diabetic. Both groups were similar in terms of age, race, having a first-degree relative with colorectal cancer and body mass index.

Results showed that diabetics had increased rates of adenoma than non-diabetics (37 percent versus 24 percent) and advanced adenoma, larger adenomas and/or with more abnormal cells (14 percent versus 6 percent). Researchers compared 245 obese women with 321 non-obese women and found that the obese women had a higher rate of adenoma (32 percent versus 22 percent). Obese diabetics compared with non-obese, non-diabetics had increased rates of any adenoma (42 percent versus 23 percent) and advanced adenoma (19 percent versus 7 percent). A multivariate analysis that took into account age, race, diabetes, hypertension, cholesterol levels, body mass index, and NSAID use showed that diabetes was a risk factor for both adenomas and advanced adenomas and increased age was a risk factor for adenomas.

"This study took a careful look at women with diabetes to determine how gender might impact the diabetes-colorectal cancer connection, and results show colon cancer is indeed a concern for diabetic women," said Jill E. Elwing, M.D., of Washington University and lead study author. "Colorectal cancer screening is critical for this population, as their diabetic condition raises their risk of colorectal cancer."

Patients With Coronary Artery Disease Are At High Risk For Developing Colorectal Cancer and Adenoma: An Interim Analysis of a Prospective Study [Abstract 208]

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Colorectal cancer is one of the most common but curable cancers, when caught early. This underscores the importance of identifying high risk patients and screening them to ensure early detection and treatment. Investigators from the University of Hong Kong conducted a prospective study to evaluate potential risk factors for colorectal cancer and found that patients with coronary artery disease (CAD) were also prone to colorectal cancer and adenoma, most likely as a result of common risk factors for both diseases. Both conditions share risk factors including male sex, old age, diabetes, smoking, high fat diet, sedentary life style and high body mass index (BMI).

Researchers administered coronary exams in 307 patients, diagnosing coronary artery disease (CAD) in those who had at least 50 percent blockage in one of the main heart arteries. The group of patients with CAD (46.3 percent) showed a higher incidence of adenomas and cancer than the patients who did not have CAD (30.3 percent versus 19.4 percent), including having larger adenomas with abnormal cells (16.9 percent versus 6.7 percent). Five cases of colorectal cancers were detected in the CAD group (3.5 percent) and none were detected in the group that did not have CAD. Analysis of the data showed a strong association between colorectal cancer and adenomas and CAD, with male smokers most at risk to have both diseases.

"Patients with CAD are at high risk of developing colorectal adenomas," said Annie On On Chan, M.D., University of Hong Kong and lead study author. "The two diseases share risk factors, and screening by colonoscopy of these patients should be mandatory to help prevent the disease and, if necessary, encourage early treatment."

Source: American Gastroenterological Association