But what if you opened your mailbox one day to find an at-home test kit, no doctor's appointment needed?
The dreaded colonoscopy may get the most attention but a cheap, old-fashioned stool test works, too and when California health care giant Kaiser Permanente started mailing those tests to patients due for a colon check, its screening rates jumped well above the national average.
Now specialists are looking to Kaiser and the Veterans Affairs health system, another program that stresses stool-tests, for clues to what might encourage more people to get screened for a cancer that can be prevented, not just treated, if only early signs of trouble are spotted in time.
"By overselling and overpromising colonoscopies, we've put up barriers for people" to get any type of screening, says Dr. T.R. Levin, Kaiser Permanente's colorectal cancer screening chief in northern California.
Everyone is supposed to get screened for colorectal cancer starting at age 50, but U.S. data shows just 55 percent do. That's better than a decade ago when screening rates hovered below 30 percent, and both new cases and deaths have dropped as a result.
But about 150,000 people still are diagnosed with colorectal cancer each year, and nearly 50,000 die. The Centers for Disease Control and Prevention says proper screening could eliminate many new cases, because regular colon checks can remove precancerous growths called polyps before the cancer has time to form.
Colonoscopies where doctors use a long, flexible tube to visually inspect the colon now account for 80 percent of all screening, a panel of specialists convened by the National Institutes of Health reported this month.
The $20 stool test usually handed over by a doctor, performed at home and then mailed to a lab is considered as effective if properly used once a year. But its use has dropped as colonoscopies took center stage.
Many doctors recommend colonoscopies as "one-stop shopping: You get screened and can get treated with one intervention," explains NIH panel member Dr. Lawrence Friedman of Harvard Medical School and Tufts University.
Sedation means it doesn't hurt, although it requires a day of bowel-cleansing preparation and can exceed $1,000. But colonoscopies allow removal of polyps on sight. If no problems are found, they're only required once a decade. They're also the required next step when the stool test or other screenings signal a possible problem.
Other options: sigmoidoscopy, an exam of the lower colon only, and the new virtual colonoscopy, a new X-ray exam offered in only limited places.
The NIH panel concluded that people should pick the screening option best for their own needs and comfort.
But it urged eliminating financial barriers. Both out-of-pocket test costs and access to a regular health provider to advise about the each option's pros and cons are hurdles.
Indeed, researchers at the Fred Hutchinson Cancer Center last week reported racial disparities in colon cancer are widening, suggesting unequal improvements in screening access. In 1992, blacks were 60 percent more likely than white to be diagnosed with late-stage colorectal cancer; by 2004, that likelihood had doubled.
Medicare pays for colorectal screening with the exception of virtual colonoscopy but that government-run insurance program is for people 65 and older. So 22 states and four tribal organizations are about to begin free screening for low-income 50- to 64-year-olds, with CDC funding. Florida is offering both the stool test and colonoscopies; other states are choosing one or the other and will track public acceptance.
The NIH panel also pointed to Kaiser Permanente's ability to track down people due for screening and pull them in without waiting on them to show up in a doctor's office.
How? Combing electronic medical records of northern California patients, Kaiser learned in 2005 that only about 40 percent who needed a colon check had gotten one. The health maintenance organization already paid for colonoscopies and sigmoidoscopies, and still does for those who prefer them. But it tried mailing out stool kits in hopes of catching people wary of invasive testing with phone calls to those who didn't return them.
Last year, screening rates rose to 75 percent.
"It's kind of like doing your own science experiment at home," said Bob Cach, 56, of Livermore, Calif., recalling instructions for that first mailed test. He did fine.
But this year's kit signaled Cach had a problem. A follow-up colonoscopy removed a polyp, still benign. He's grateful it was caught, having watched his wife battle colon cancer over the past year.
"I am an advocate now for screening."