Q1: What are the leading causes of colon cancer?
Dr. Tierney: The most important thing is that colon cancer becomes more common as we get
older. One of the effects of aging in the colon is that the cells that line the colon undergo a
process of growth and polyps can develop. And these polyps are typically benign, small growths
that over the course of years can turn into colon cancer. And that long period, that long interval
of years of growth provides us with an opportunity to detect and remove those polyps an prevent
the cancer. So aging is probably the most important issue in terms of a risk factor for developing
colon cancer. And over the age of 50 is when it really becomes very common.
The other risk factors that we are aware of related to colon include diet. People that have a high
fat and low fiber diet tend to have a higher rate of colon cancer.
There are some other factors that are important, and that is family history, is critical. If you have
a family member who's had colon cancer, or even colon polyps, that is something for you to
discuss with your doctor because that puts you in a whole different risk category for developing
colon cancer as time goes on.
Q2: What are some of the symptoms of colon cancer?
Dr. Tierney: The symptoms of colon cancer including bleeding in the stool, abdominal pain or
change in the bowel habit. So if you've had fairly regular bowel habits and all of a sudden at the
age of 53, 54, something's changed about your bowel habits, you need to talk to your doctor
about that because sometimes these subtle changes in bowel habits can be a sign of a problem
in the colon, most specifically colon cancer. Constipation or diarrhea. So if it goes one way or the
other, if there's a change in your bowel habits, that's something to report. Weight loss is another
symptom that typically occurs very late in the process of colon cancer.
Q3: What progress has been made in screening and preventing colon cancer?
Dr. Tierney: We do know that these interventions that we use for screening do prevent colon
cancer because the number of cancer deaths in this country is declining. And it's estimated--so
over the past 20-30 years we've seen about a 20% decrease in colon cancer deaths in this
country. And it's estimated that about half of that decrease in cancer deaths is due to improved
screening.
Q4: Is colonoscopy the best screening procedure?
Dr. Tierney: One of the main obstacles to us achieving a perfect screening rate, and by that I
mean everybody in the world would get screened for colon cancer with colonoscopy, which is
probably the most effective test in terms of preventing colon cancer.(@3:26)
Q5: How does colonoscopy work?
Dr. Tierney: The endoscopist or the person performing the procedure would take a long
endoscope which has a camera on it--on the tip. And the endoscope is inserted into the rectum,
that lowest part of the colon, and advanced all the way around the colon. That's the goal, is to
inspect the entire colon. And the advantage of colonoscopy is that the endoscopist or the
physician performing the procedure can perform therapy during the procedure. By therapy, I
mean remove the polyps.
Q6: What does a patient need to do to prepared for a colonoscopy, and is it painful?
Dr. Tierney: For a colonoscopy a patient should expect to take the day off from work or whatever
their other activities are. The day prior to the procedure they have to take some medication to
cleanse the colon so that the inspection can be as effective as possible. That's-- most patients
when you talk to them, when they come in for their procedure, and they're done with the
procedure, what-- 90% of them say that's the worst part of their procedure, is having to go
through the preparation of cleaning the colon.
The day of the procedure is typically--it's in a hospital or an ambulatory endoscopy center. And
the procedure does almost always involve sedation, so the patient has an IV placed, they are
given a combination of medications both to take away discomfort and to sedate them--make
them more relaxed. With that combination of medications, the vast majority of the patients get
through the procedure without recognizing it. Without any discomfort.
Q7: How often should you have a colonoscopy?
Dr. Tierney: Now if you don't have a family history and you have a colonoscopy at age 50 and it's
normal, then ten years is the recommended time to repeat that. Now with a family history, again
it gets really into the details of what the family history is. But if you friend's brother had a colon
cancer under the age of 60, and he or she had a colonoscopy and it's normal, then typically it's
every five years with that family history.
Q8: If the colonoscopy finds cancer, what happens next?
Dr. Tierney: If a colonoscopy diagnosed cancer, hopefully it's been diagnosed in the early stage.
And the next step would be to go through some testing to help determine what the state of that
cancer was. And that would usually require a CAT scan of the abdomen to look at the liver and
also to see if there's any sign that the cancer has spread to other organs. If that cancer has not
spread to other organs, almost always the next step is going to be surgery of the colon to
remove that segment of the colon that has the cancer in it. When that surgery is done, some
further information is gained as a result of inspecting or examining, from a pathology standpoint,
the cancer. And that information can then be used to determine if chemotherapy is necessary. So
that's a fairly typical sequence of events. There are some patients that if we catch it early enough
and do surgery, that's it. They're done. They're cured from their cancer. They would still need to
have surveillance and monitoring over time to make sure the cancer doesn't come back and also
to have colonoscopies on a much more frequent interval because now they've got, developed
cancer, they're at a much higher risk of getting cancer again in the future and in other parts of
their colon.