Dear Dr. Roach: I am an 82-year-old woman in good health, and I don’t take any medications. My first five colonoscopies were five years apart from each other because polyps were found each time, all of which ended up testing negative for cancer. My most recent colonoscopy (at age 81) was negative for polyps, so I was told that I wouldn’t be having any more colonoscopies because of my age and the risk of the procedure.
My parents lived to 90 and 96, as did three of my grandparents, so I am hoping for a similar life expectancy. Because of this, I am concerned about stopping colonoscopies now and would appreciate your thoughts.
S.A.
There isn’t a definitive answer. Before recommending any procedure, physicians ought to consider the risks and benefits of performing the procedure against the outcome if the procedure isn’t done. For preventive health manoeuvres like a colonoscopy, it’s particularly important to be sure that there is more expected benefit than harm.
A colonoscopy has a small risk of harm at the time of the procedure. People can have an adverse effect because of the sedation that is used. More commonly, a small perforation can happen during the colonoscopy, even in the most expert hands. A review of published data of more than 20 years estimates that the perforation rate is about one per 3,500 colonoscopies. These risks are small, but not zero.
The benefit of a colonoscopy takes time to accrue. Removing a polyp might prevent cancer seven to 10 years later. Consequently, in average-risk people with a life expectancy of less than 10 years or so, you can expect to cause more harm than benefit.
Unfortunately, we are not very good at predicting life expectancies. On average, an 86-year-old woman (the age you would be if you were to undergo another colonoscopy) should live about six more years, but you are likely to have a longer-than-average life span due to your good genes.
My best estimate is that the risks of a colonoscopy equal the benefits for you if you were due for a colonoscopy now, given your age, family history and results of previous colonoscopies. But since you are due to have your next one at age 86, the harms will probably outweigh the benefits. If your gastroenterologist had chosen the more conservative 10-year recommendation for a person without polyps, you would be 91 and at a higher risk for complications.
In a person of average risk (meaning a person without a personal or strong family history of colorectal cancer), a screening colonoscopy at any age greater than 85 is more likely to cause harm than benefit. However, it’s your body, and you get a vote. You might want to talk to your gastroenterologist about having one last colonoscopy at age 85.
Dr. Roach Writes: A recent column asked about relief from allergy symptoms following the COVID vaccine. I had said that I couldn’t find any reports of this, but several readers wrote in to say they, too, have noticed these symptoms. I’m still not convinced that the COVID vaccine is responsible, any more than that it causes certain illnesses weeks after the vaccine, but I did want to report that other people have noted this.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to [email protected]
