点击显示 收起
May 23, 2006 -- People aged 80 and older may want to talk to their doctors about whether or not they should get colonoscopies to screen for colorectal cancercolorectal cancer.
For people in that age range, screening colonoscopy "should be performed only after careful consideration of potential benefits, risks, and patient preferences," write Otto Lin, MD, MSc, and colleagues in The Journal of the American Medical Association.
Lin works in Seattle at Virginia Mason Medical Center's gastroenterology section. His study included 1,244 people aged 50 and older who got screening colonoscopies at Seattle's Virginia Mason Medical Center from January 2002 to January 2005.
The researchers predict that the oldest participants would gain the least time, in terms of life expectancy, by getting those colonoscopies.
Lin's study has "minor shortcomings" but concludes that "sound screening decisions involving elderly patients should consider their individual circumstances," states a journal editorial.
About Colonoscopy
In colonoscopy, doctors use a thin, flexible tube with a tiny camera to check a patient's colon and rectum. Colonoscopy is one of the tests that check for colorectal cancercancer and abnormal growths, such as polyps, that may develop into colorectal cancer. During a colonoscopy, biopsies can be taken and polyps removed.
Colonoscopy is highly regarded, but it has risks. Patients need anesthesia for the invasive procedure. In rare cases, the colon may bleed or perforate during the colonoscopy procedure.
As with many diseases, early detection of colon cancer may make a big difference to patients' survival. Colon cancer screening tests are recommended for everyone aged 50 and older; people at high risk for colorectal cancer may need to start screening earlier.
Colorectal cancer is the No. 2 cause of cancer-related deaths in the U.S. for men and women combined, according to the American Cancer Society.
Screening for Colorectal Cancer
Screening methods for colorectal cancer include:
There is no upper age cutoff for those tests. Lin's study doesn't change that.
Colonoscopy Study
Lin's study included 1,034 people in their early 50s, 147 people in their late 70s, and 63 people who were at least 80 years old. None had already been diagnosed with colon cancer.
The oldest participants were the most likely to have their colonoscopies show abnormal growths that may or may not have been cancerous. Such growths were seen in nearly 14% of people in their early 50s, almost 27% of those in their late 70s, and about 29% of those age 80 and older.
The researchers did calculations to estimate how much extra time colonoscopy added to participants' life expectancy.
Even though abnormal growths were more common in older people, screening colonoscopy in people aged 80 and older "results in only 15% of the expected gain in life expectancy in younger patients," write Lin and colleagues.
The researchers estimate that screening colonoscopy added 0.13 years -- about a month and a half -- to the life expectancy of participants aged 80 and older, compared to 0.85 years -- about 10 months -- for those in their 50s.
Study's Limits
Lin and colleagues didn't study participants over time, so it's not clear if their calculations were right.
The mathematical model used by Lin's team to estimate life expectancy gains may not be perfect, partly because relatively few participants were in their 80s or older, but those shortcomings were "minor," writes editorialist Timothy Church, PhD.
Church works at the University of Minnesota's School of Public Health. He wasn't involved in Lin's study.
Many serious health problems -- including cancer -- become more common with age. But some elders are in great shape, and some people decades younger may have health issues. So people of any age should feel free to discuss the risks and benefits of any procedure or treatment with their doctors.
SOURCES: Lin, O. The Journal of the American Medical Association, May 24/31, 2006; vol 295: pp 2357-2365. American Cancer Society: "What Are the Key Statistics for Colorectal Cancer?" Church, T. The Journal of the American Medical Association, May 24/31, 2006, vol 295: pp 2411-2412. News release, JAMA/Archives.