Extra CT Colonography Findings
Extracolonic findings during CT colonography are common, but identify a substantial number of clinically important abnormalities in men, regardless of their risk for colorectal cancer, reported Judy Yee, M.D., of the University of California at San Francisco, and her colleagues.
CT colonography identified 596 extracolonic abnormalities in 315 of 500 male patients screened for colorectal cancer. Of 45 patients with abnormalities deemed clinically important, 35 had not been previously identified; they included renal and adrenal masses, pulmonary nodules, and abdominal aortic and iliac artery aneurysms (Radiology 2005;236:519–26).
The percentage of patients with clinically important extracolonic findings did not differ significantly between the 194 patients who were at average risk for colorectal cancer and the 306 who were at high risk (6.2% vs. 10.8%, respectively). Follow-up imaging studies were performed in 25 of the 35 patients with previously undiagnosed lesions; 13 of the patients required surgery or further monitoring. The cost of additional imaging performed because of extracolonic findings averaged $28 per patient.
Hemochromatosis Screening
Nearly all individuals who are identified as having hemochromatosis through genetic screening of cheek-brush samples for HFE mutations are willing to undergo management and treatment, according to a prospective study.
Martin B. Delatycki, M.B., of the University of Melbourne, and his associates detected homozygous Cys282Tyr mutations in HFE in 51 of 11,307 individuals who attended workplace screening sessions; 4 patients were already aware of their condition. Almost all of the newly identified homozygous individuals (46 of 47) agreed to enter into an appropriate program of medical management. In homozygous patients, elevated fasting transferrin saturation levels were found in 19 of 23 men and 11 of 23 women. All patients with high levels of serum transferrin underwent regular phlebotomy to reduce ferritin levels to within the normal range. Liver biopsies performed in four of the six men who met criteria for a biopsy showed either advanced precirrhotic liver fibrosis or moderate hemosiderosis with mild portal fibrosis (Lancet 2005;366:314–6).
New-Onset Diabetes as Marker New onset of diabetes in patients older than 50 years has the potential to be a marker for early pancreatic cancer, reported Suresh T. Chari, M.D., and colleagues at the Mayo Clinic, Rochester, Minn.
In a review of 2,122 Rochester residents who were 50 years or older and developed diabetes at some point during 1950 through 1994, 18 (0.85%) went on to have pancreatic cancer. The cancer was identified an average of about 6 months after diabetes criteria were met. In 10 of those patients, the cancer was diagnosed less than 6 months after first meeting criteria for diabetes. The crude 3-year incidence of pancreatic cancer in patients with diabetes 50 years of age or older was 310 per 100,000 patient-years. Diabetic patients with pancreatic cancer were about 4.5 times more likely to have first met criteria for diabetes on or after age 70 years than were diabetic patients without pancreatic cancer (Gastroenterology 2005;129:504–11).
“For hyperglycemia to be a clinically useful marker of early cancer one will have to screen asymptomatic individuals for hyperglycemia,” and the success of the strategy “will depend largely on our ability to differentiate pancreatic cancer-induced diabetes from type 2 diabetes using a serologic marker,” the investigators wrote. “Because our population was neither screened for diabetes nor [screened] for pancreatic cancer, the benefit of screening for pancreatic cancer using diabetes or hyperglycemia as a marker cannot be answered by the present study and deserves a prospective analysis.”
Hereditary Colorectal Ca
The median age of onset of colorectal cancer in individuals of families with mismatch repair gene mutations for hereditary nonpolyposis colorectal cancer may be much older than previously reported, according to Heather Hampel, M.D., of Ohio State University, Columbus, and her colleagues.
The median age at diagnosis was 54 years in men and 70 years in women in a group of 70 Finnish families at risk for hereditary nonpolyposis colorectal cancer (HNPCC) that comprised 88 probands and 373 individuals who tested positive for a germline mutation in MLH1 or MSH2 (Gastroenterology 2005;129:415–21).
Those ages are 10–15 years higher than the previous estimates of age at onset for colorectal cancer among HNPCC patients in the literature, which are typically 44–45 years. “Our data strongly suggest that in the diagnosis of HNPCC, limiting molecular studies to patients with an early age at diagnosis will miss many cases,” the researchers wrote. Microsatellite instability and immunohistochemical staining “would best be applied to all new colorectal cancer cases and not just to a limited high-risk subset.”