Virtual Colonography Detects Unsuspected Extraclonic Cancers

Abstract

A study of >10,000 adults found that >1 in every 200 asymptomatic people screened with computed tomographic (CT) colonography, or virtual colonoscopy, had clinically unsuspected malignant cancer and more than half of cancers were extracolonic. The findings were published in the April issue of the journal Radiology. “We are finding that virtual colonoscopy screening actually identifies more unsuspected cancers outside of the colon than within it,” says lead author Perry J. Pickhardt, MD, professor of radiology and chief of GI Imaging, at the University of Wisconsin School of Medicine & Public Health. “As with asymptomatic colorectal cancers identified by virtual colonoscopy screening, these cancers are often detected at an early, curable stage.” In addition to the intended colorectal evaluation, CT colonography also provides for limited assessment of extracolonic structures, including the abdomen, pelvis, and lungs. Additional diagnostic imaging work-up for unsuspected extracolonic findings is performed in approximately 6% of cases, nearly half of which ultimately prove to be clinically relevant, the authors note. The researchers retrospectively determined the detection rates, clinical stages, and short-term patient survival for all unsuspected malignancies in an asymptomatic screening population. They reviewed the medical records of 10,286 adults (5,388 men and 4,898 women) with a mean age of 59.8 years who were evaluated at either the University of Wisconsin or the National Naval Medical Center. All of the adults had undergone colorectal cancer screening with virtual colonoscopy at the two centers between April 2004 and March 2008. The mean time for follow-up was 30.2 months. Unsuspected cancer was confirmed in 58 patients, including 33 women and 25 men. Invasive colorectal cancer was found in 22 patients, and extracolonic cancer was found in 36 patients. Cancers in 31 patients (53.4%) were stage 1 or localized cancers. Extracolonic malignancies included renal cell carcinoma (n = 11), lung cancer (n = 8), non-Hodgkin lymphoma (n = 6), or a variety of other tumors (n = 11). At the most recent clinical follow-up (mean, 30.0 months; range, 12–56), 3 patients (5.2%) had died of their cancer. “To our knowledge, none of the patients who presented with stage 1, stage 2 or localized disease at diagnosis has progressed to a higher stage,” Pickhardt says. “The fact that so many of the cancers in our study were localized or detected at an early stage appears to have positively affected survival.” See: Radiology 2010;255:1 orhttp://radiology.rsna.org/content/255/1/83.full.