An interim analysis of a study presented today at the 39th Annual Digestive Disease Week (DDW) Conference found that, among patients at increased risk for colorectal cancer who completed an annual fecal immunochemical (FIT) test, detection of cancerous lesions occurred an average of 26.5 months earlier than would have occurred during the three- or five-year study-required colonoscopy. Detection of precancerous lesions in this group occurred 18.4 months earlier.
Data presented reflect results to date of the study "The Value of Interval Fecal Occult Blood Testing in Colonoscopy-Based Surveillance Program (CSP) for People at Increased Risk for Colorectal Cancer" conducted at the Flinders Centre for Innovation in Cancer of South Australia, in which individuals with a family or personal history of colorectal cancer or adenoma were entered into a CSP. In each intervening year between required colonoscopies, individuals were offered a FIT test to complete at home, using a brush sampling method to collect water-based samples for laboratory analysis. Study groups included a screening cohort (n=1736), broken down into a FIT cohort (n=1071) of patients who returned at least one valid interval FIT test with subsequent colonoscopy and a non-FIT cohort (n=665), comprised of patients who did not complete a FIT test. Study-required colonoscopies were scheduled at either three or five year intervals, according to the patient's medical situation.
The interim report showed that, while the same number of colorectal cancers were discovered in the FIT cohort (n=14) and the non-FIT cohort (n=14), colorectal cancers in the FIT cohort were detected an average of 26.5 months earlier than they would have been during a study-required colonoscopy.
Patients in the FIT cohort diagnosed with treatable Stage I (Dukes Stage A) cancer (n=5), were diagnosed an average of 17.5 months earlier than they would have been with a study-required colonoscopy alone, and those with treatable Stage II (Dukes Stage B) cancer (n=2) were diagnosed an average of 21.8 months earlier than they would have been with a study-required colonoscopy alone. Detection of advanced adenomas in the FIT cohort (n=60; non-FIT n=54) occurred 18.4 months earlier than would have occurred during the study-required colonoscopy.
Overall, the interim report showed that interval FIT testing under this study program detected 86 percent (12 of 14) of colorectal cancers and 63 percent (60 of 96) of advanced adenomas greater than 10 mm.
Colorectal cancer is the second leading cause of cancer death in the United States(1), but when found early and treated, the five-year relative survival rate for colon cancer is 90 percent.(2) Currently, less than 40 percent of colorectal cancers are found early.(3) The new data presented today at DDW suggest that annual colorectal screening with FIT tests may help increase early detection.
"Our interim report indicates that undertaking annual FIT testing in high-risk groups -- between planned surveillance colonoscopies -- is valuable because it reduces delays in the diagnosis and treatment of colorectal cancer and advanced adenomas," said primary investigator Graeme P. Young, MD, FRACP, Professor of Gastroenterology and Academic Head of GI Services, Director, Flinders Centre for Innovation in Cancer of South Australia. "For the medical community dedicated to preventing and treating this major disease, we now have evidence that annual screening of high-risk patients with a convenient, take-at-home test can catch not only colorectal cancer earlier but advanced adenomas as well, given the notable CSP study program sensitivity of 63 percent."
American Cancer Society (ACS) guidelines recommend colonoscopy every five years for patients with a family history of colorectal cancer and for patients with a personal history of colorectal cancer who have had a normal 3-year colonoscopy, and more frequent colonoscopies if polyps are detected or a risk of hereditary nonpolyposis colorectal cancer (HNPCC) is suspected. For patients at average risk over the age of 50, ACS guidelines include colonoscopy every ten years and an annual FIT test among the recommended screening options.(4)
The study was conducted using the InSure(R) FIT(TM) test, a take-at-home annual colorectal cancer screening test from Enterix, Inc., a wholly-owned subsidiary of Quest Diagnostics. InSure FIT, and the recently launched InSure Quik F I T(TM), each use a patient-friendly, long-handled blue brush to collect two water-based samples for analysis. The tests are completed at home, and samples are submitted to a Quest Diagnostics laboratory (InSure FIT) or returned to the physician's office (InSure Quik F I T) for evaluation.
The study presented at Digestive Disease Week was funded by grants from the National Health and Medical Council of Australia and Enterix Australia Pty. Ltd. Enterix was acquired by Quest Diagnostics in September 2006. Neither company participated in the study's data analysis or influenced the conclusions of the researchers.
The study abstract is published in the April 2008 supplement of Gastroenterology.