American Board of Internal Medicine (ABIM) Certification Practice Exam

The recommended frequency for flexible sigmoidoscopy in patients with rectal cancer during the first three years after therapy is every 3 to 6 months. This interval is critical as the risk of recurrence is highest in the first few years following treatment. Regular monitoring within this timeframe allows for the early detection of any potential recurrence or new lesions, which is essential for timely intervention. During the initial years post-treatment, the likelihood of developing local or distant disease is increased, making close surveillance necessary. The 3 to 6 months schedule balances the need for vigilance with the practicality and safety of the procedure. As a patient's risk for recurrence decreases over time, the frequency of surveillance can be adjusted accordingly. Other options, like monthly or quarterly sigmoidoscopies, are not recommended due to the increased burden on the patient and healthcare resources without a proportional benefit, as well as the potential risks associated with more frequent procedures. Conversely, only scheduling sigmoidoscopies once a year may not provide sufficient monitoring during the critical early years after treatment.