Those who want to be screened may lack ability. Reading and language barriers can make instructions useless. Older patients with poor vision or manual dexterity cannot collect stool specimens. Limited insurance and lack of access to physicians can create further impediments. Finally, patients need reinforcement.
Few patients remember, five years hence, that it is time for another sigmoidoscopy.
Reminders from the physician who performed the test help little if the patient has moved or, as occurs frequently in managed care, has acquired a new physician. The secret to changing behavior lies in recognizing the barriers that apply and crafting smart solutions to address them. In promoting colorectal cancer screening, it is worth remembering that no single test is ideal. The only direct trial evidence that screening reduces mortality involves fecal occult blood testing. The evidence for sigmoidoscopy comes from case-control studies.