That news comes from researchers at Yale University's medical school, including Cary Gross, MD.
In colonoscopy, doctors guide a thin, flexible tube with a tiny camera through the patient's colon to check for abnormalities, including cancer and precancerous growths.
With about 60,000 new cases of colon cancer every year among those 65 and older, even a 4% rise in early diagnosis can have an impact, Gross' team notes.
The new study, published in The Journal of the American Medical Association, is a snapshot of colonoscopy use in Medicare patients.
Medicare didn't cover colonoscopy from 1992 to 1997. From 1998 to 2001, Medicare offered limited coverage, expanding to universal coverage in 2001.
Gross' team studied data from all three periods.
More Medicare patients got a colonoscopy after coverage became available, the study shows. That is, the Medicare colonoscopy rate was higher from 1998 to 2001 than from 1992 to 1997.
But the colonoscopy rate didn't change when Medicare expanded its limited colonoscopy coverage to universal coverage.
The researchers also analyzed therecords of nearly 45,000 people aged 67 and older diagnosed with colon from 1992 to 2002.
They found that earlier detection became more common after Medicare covered colonoscopy.
For instance, when Medicare didn't cover the procedure, the proportion of patients diagnosed at an early stage was 22.5%.
That figure rose to 25.5% when Medicare offered limited colonoscopy coverage and increased to 26.3% when it provided universal coverage, the study shows.
Room for Improvement
The findings are "encouraging," even though Medicare's impact on early detection was "modest," write Gross and colleagues.
Study after study has shown too few people get a colonoscopy -- or any other screening for colon cancer -- and this study is no exception.
"The majority of patients are still being diagnosed with later-stage disease," the researchers write.
Editorialist Arden Morris, MD, MPH, notes "it remains to be seen" if the trend toward earlier detection will continue.
Morris works in Ann Arbor at the University of Michigan's division of colorectal surgery.
The National Cancer Institute recommendsscreening for everyone 50 and older.
People at high risk of colon cancer may need to start screening earlier. Check with your doctor about when you should begin.
Besides colonoscopy, other screening methods include:
- Flexible sigmoidoscopy: Similar to colonoscopy, but covers a smaller section of the colon.
- Fecal occult blood test: A lab test that checks for hidden blood in stool.
- Double-contrast barium enema: X-ray of the colon, highlighted by liquid barium.
- Digital rectal exam: Often part of a routine physical exam; doctor or nurse inserts a lubricated, gloved finger into the rectum to feel for abnormal areas in the lower part of the rectum.
Ask your doctor which test is appropriate for you.