Fecal Occult Blood Testing After Negative Colonoscopy
Fecal Occult Blood Testing After Negative Colonoscopy
Objectives: Annual fecal occult blood testing (FOBT) is often continued in patients who have had a recent negative colonoscopy, despite recommendations to the contrary. This prospective study aimed to determine the proportion of patients with a positive FOBT who had adenomas and cancers on colonoscopy stratified according to the duration of time since the last negative colonoscopy.
Methods: A total of 1,119 asymptomatic average-risk patients ≥50 years of age referred for a positive FOBT were prospectively identified and stratified by the duration of time since the last colonoscopy (never, >10 years, 5–10 years, or <5 years). The proportion of patients in each category with adenomas of any size, adenomas ≥10 mm, advanced neoplasms, and cancers was assessed.
Results: The mean age (68.9±9.6 years), sex (95.2% male), and race (48.1% white, 32.1% black, 15.6% Hispanic, and 4.2% other) did not differ between the four groups. Overall, adenomas of any size were detected in 42.8% of patients, adenomas ≥10 mm in 14.7%, advanced neoplasms in 20.7%, and cancers in 7.3%. Advanced neoplasms were detected in 30.4% of patients who have never had a colonoscopy, 27% in those who have had one greater than 10 years prior, 10.0% in 5–10 years prior, and 1.1% in less than 5 years prior.
Conclusions: In asymptomatic average-risk patients with a negative colonoscopy within the last 5 years, the prevalence of adenomas is low, and no patient was diagnosed with cancer. These findings support the CDC recommendations to suspend annual FOBT for up to 5 years after a negative colonoscopy.
CRC Epidemiology and Screening Strategies
Colorectal cancer (CRC) is the second leading cause of cancer death in the United States. The National Cancer Institute and the Centers for Disease Control (CDC) estimate that there are approximately 140,000 new cases of CRC and around 50,000 CRC-related deaths per year. It has been well established that screening for CRC aids in the early detection of CRC and reduces mortality rates up to 53%. Current screening options include annual fecal occult blood testing (FOBT), fecal immunochemical testing, multitarget stool DNA testing, flexible sigmoidoscopy, combined FOBT and flexible sigmoidoscopy, barium enema, or colonoscopy. Most major medical societies now recommend screening for CRC, and guidelines have been published.
If screening colonoscopy is performed in an asymptomatic patient at average risk for CRC, then it is generally accepted that a follow-up colonoscopy is not needed for 10 years after a negative colonoscopy. Although there is a general consensus among the major medical societies supporting a combined screening program with FOBT and flexible sigmoidoscopy, there is no consensus supporting or disproving the concomitant use of annual FOBT with colonoscopy. However, in clinical practice, interval FOBT is often performed despite a recent negative colonoscopy.
Currently, the Centers for Disease Control and Prevention recommend suspending FOBT for at least 5–10 years after a negative colonoscopy. However, this recommendation is based on "expert" opinion, and there are no published data to specifically address the optimal approach to patients with a positive FOBT who had a negative colonoscopy within the past 5–10. The aim of this prospective study was to determine the proportion of asymptomatic average-risk patients with a positive FOBT who had adenomas and cancers on colonoscopy stratified according to the duration of time since the last negative colonoscopy. We hypothesized that, in asymptomatic average-risk individuals who had a negative colonoscopy within the past 5 years, a positive FOBT likely represents a false positive and that repeating a colonoscopy will have a low yield for significant lesions.
Abstract and Introduction
Abstract
Objectives: Annual fecal occult blood testing (FOBT) is often continued in patients who have had a recent negative colonoscopy, despite recommendations to the contrary. This prospective study aimed to determine the proportion of patients with a positive FOBT who had adenomas and cancers on colonoscopy stratified according to the duration of time since the last negative colonoscopy.
Methods: A total of 1,119 asymptomatic average-risk patients ≥50 years of age referred for a positive FOBT were prospectively identified and stratified by the duration of time since the last colonoscopy (never, >10 years, 5–10 years, or <5 years). The proportion of patients in each category with adenomas of any size, adenomas ≥10 mm, advanced neoplasms, and cancers was assessed.
Results: The mean age (68.9±9.6 years), sex (95.2% male), and race (48.1% white, 32.1% black, 15.6% Hispanic, and 4.2% other) did not differ between the four groups. Overall, adenomas of any size were detected in 42.8% of patients, adenomas ≥10 mm in 14.7%, advanced neoplasms in 20.7%, and cancers in 7.3%. Advanced neoplasms were detected in 30.4% of patients who have never had a colonoscopy, 27% in those who have had one greater than 10 years prior, 10.0% in 5–10 years prior, and 1.1% in less than 5 years prior.
Conclusions: In asymptomatic average-risk patients with a negative colonoscopy within the last 5 years, the prevalence of adenomas is low, and no patient was diagnosed with cancer. These findings support the CDC recommendations to suspend annual FOBT for up to 5 years after a negative colonoscopy.
Introduction
CRC Epidemiology and Screening Strategies
Colorectal cancer (CRC) is the second leading cause of cancer death in the United States. The National Cancer Institute and the Centers for Disease Control (CDC) estimate that there are approximately 140,000 new cases of CRC and around 50,000 CRC-related deaths per year. It has been well established that screening for CRC aids in the early detection of CRC and reduces mortality rates up to 53%. Current screening options include annual fecal occult blood testing (FOBT), fecal immunochemical testing, multitarget stool DNA testing, flexible sigmoidoscopy, combined FOBT and flexible sigmoidoscopy, barium enema, or colonoscopy. Most major medical societies now recommend screening for CRC, and guidelines have been published.
Screening Colonoscopy and Interval FOBT
If screening colonoscopy is performed in an asymptomatic patient at average risk for CRC, then it is generally accepted that a follow-up colonoscopy is not needed for 10 years after a negative colonoscopy. Although there is a general consensus among the major medical societies supporting a combined screening program with FOBT and flexible sigmoidoscopy, there is no consensus supporting or disproving the concomitant use of annual FOBT with colonoscopy. However, in clinical practice, interval FOBT is often performed despite a recent negative colonoscopy.
CDC Recommendations and Our Aims
Currently, the Centers for Disease Control and Prevention recommend suspending FOBT for at least 5–10 years after a negative colonoscopy. However, this recommendation is based on "expert" opinion, and there are no published data to specifically address the optimal approach to patients with a positive FOBT who had a negative colonoscopy within the past 5–10. The aim of this prospective study was to determine the proportion of asymptomatic average-risk patients with a positive FOBT who had adenomas and cancers on colonoscopy stratified according to the duration of time since the last negative colonoscopy. We hypothesized that, in asymptomatic average-risk individuals who had a negative colonoscopy within the past 5 years, a positive FOBT likely represents a false positive and that repeating a colonoscopy will have a low yield for significant lesions.
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