Dr. Edward Chu, Colorectal Cancer Awareness
2009
March 1, 2009
Welcome to Yale Cancer Center Answers with Dr. Ed Chu and Dr. Francine Foss, I am Bruce Barber. Dr. Chu is Deputy Director and Chief of Medical Oncology at Yale Cancer Center and an internationally recognized expert on colorectal cancer. Dr. Foss is a Professor of Medical Oncology and Dermatology and is an expert in the treatment of lymphomas. If you would like to join the discussion, you can contact the doctors directly at canceranswers@yale.edu or 1888-234-4YCC. This evening, in recognition of the fact that March is Colorectal Cancer Awareness Month, Dr. Foss sits down for a chat on this subject with her co-host Dr. Chu.
Foss
Ed, I know that you have been interested in colon cancer for a
long time and worked on this at the National Cancer
Institute. Can you relate to us what first got you interested
in colorectal cancer, and a little bit about your research work as
well?
Chu
I think it was probably a bit of genetics and environment. As you
know, both of my parents were cancer researchers and initially
started their careers at Yale Cancer Center and then moved up to
Brown. They both were involved in basic research focusing on
colorectal cancer, so I think having grown up in that environment
influenced me. My research in college and at med school focused on
colon cancer, and then when I went to do my fellowship at the
National Cancer Institute I worked closely with Carmen Allegra and
Bruce Chabner and I focused initially on the basic research of
colon cancer and trying to understand how drugs work and do not
work in colon cancer. I then extended my interest to developing new
agents for the treatment of colorectal cancer.
Foss
So I guess things were a little bit unusual in your household; you
probably talked about colon cancer from the time you were very
young. How common is the disease? Most people hear about it and a
lot of us have questions about who is getting it and who is at
risk.
Chu
Even in 2009 colon cancer remains a major public health problem in
the United States and worldwide. To give you some
perspective, there will be about 150,000 new cases of colon cancer
diagnosed in the U.S. this year. It is the number three cause
of cancer in this country and it is the number two cause of cancer
death. There will be about 46,000-47,000 deaths associated with
this disease, and bringing it closer to home, here in the State of
Connecticut, in 2009 it is estimated that there will be about 2,200
new cases of colon cancer diagnosed.
Foss
What are major risk factors for colon cancer; who has to worry
about this?
Chu
By far and away the number one risk factor for developing colon
cancer is age; age greater than 50. The general recommendation for
anyone who is over 50 is that colon cancer screening must be
initiated. One of the things I would like to emphasize, and
the reason we are doing this show in March, is that March is
Colorectal Cancer Awareness Month and I
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think the key drive for us as healthcare professionals is to
highlight the importance of colon cancer screening.
Foss
Can you tell us a little bit about the screening process?
Who should be screened and what is involved in getting
screened?
Chu
Again, age by far and away, is the number one risk factor, and
anyone who is older than 50 should get colon cancer
screening. The one thing that is important to recognize is
that individuals with a family history of colon cancer, especially
for those whose family members have developed colon cancer before
the age of 50, should start getting screened much earlier.
Maybe one of the other reasons why I developed a strong interest in
colorectal cancer is because one of my mom's younger brothers, in
fact her baby brother, was first diagnosed with colon cancer at the
age of 42. Fortunately for him, he went about 10 years with
the diagnosis, but unfortunately succumbed to the disease.
Yours truly, in fact, started getting screened for colon cancer
when I was in my late 20s. I actually just had my fourth
colonoscopy one week ago.
Foss
People who have certain other diseases could be at risk as well,
and I have heard that people with inflammatory bowel disease, or
people that have had polyps, should be screened more often. Can you
talk a little bit about that?
Chu
That is an important point. Patients with inflammatory bowel
disease, either ulcerative colitis or Crohn's colitis, and in
particular individuals who have had the disease for over 10 years
duration and who have had pretty extensive involvement of their
colon, are certainly at increased risk. The other important
risk factors, just to note, are individuals with a family history
of colon cancer, but interesting enough, also a family history of
other types of cancer such as breast cancer, ovarian cancer,
stomach cancer, even brain cancer. There is a familial syndrome,
called Lynch syndrome in which there is a higher incidence of colon
cancer along with those other cancers.
Foss
At what age should a patient like that start to be screened?
Chu
In someone who has a very strong family history of colon cancer,
those other cancers, or in a situation where there is a very strong
history of polyps, generally screening may start as early as the
20s.
Foss
Can you talk a little bit about screening? What tests are
actually done?
Chu
There are a number of tests that have been recommended by the
American Cancer Society
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and the Centers for Disease Control. The simplest test is actually
a physical exam in which the physician does a rectal exam. If they
can obtain a stool specimen, they can test the stool to see if
blood is present. You may not actually see the blood as a
bright red color, but you can then do a stain to see if in fact
there is microscopic blood in the stool. Unfortunately, the
physical exam and the stool testing are pretty insensitive, so the
gold standard for colon cancer screening and early detection is a
test called colonoscopy. What a colonoscopy basically is, is a tube
with a light at the end that is inserted in the rectum and goes all
the way to the end of the large bowel so you can actually visualize
the entire colon.
Foss
People who have had colonoscopies give kind of horror stories
about how difficult it is, I know you have said you have had
colonoscopies, and I have had them myself, and I think it is
important for us to talk a little bit to people about this
procedure and how it does not necessarily have to be something to
worry about.
Chu
That is a great point that we need to highlight. I think that
what people actually get very squeamish about is the preparation.
You need to drink a fluid to try to cleanse the entire bowel so
that the procedure can visualize the bowel. Now, as I said,
my very first colonoscopy was quite some time ago and back then I
think I had to drink three or four gallons of a fluid called
GoLYTELY. It was really kind of a misnomer because it was not
so GoLYTELY. You have to drink this big bolus of fluid, you get
bloated and then you actually discharge. Now it has gotten to
the point, as I said one week ago I had my colonoscopy, where I
took pills with fluid and I found it to be much simpler and just as
effective in getting the appropriate prep for the procedure.
Foss
Can you talk a little bit about the role of x-rays in making a
diagnosis of colon cancer, and whether or not there are blood tests
that are helpful?
Chu
There has been a lot publicized recently about a test called
virtual colonoscopy, and what that is, is basically a very
sophisticated high tech CT scanning of the bowel. The
advantage of virtual colonoscopy is that it takes about 10 or 15
minutes and basically once the procedure is done the individual can
go back to work. It is important to note that you still need
to take the same prep as you do with the real colonoscopy, and the
other potential issue is that with very small polyps, small tumors,
it is not as sensitive at picking them up as colonoscopy. If there
is anything suspicious that is seen on the virtual colonoscopy,
that individual still needs to then have the colonoscopy and have a
biopsy performed.
Foss
Should people worry that something might be missed if they have a
virtual colonoscopy?
Chu
If the virtual colonoscopy is entirely normal, then that is a
discussion that needs to be had
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with the individual's primary care physician and GI
specialist. What we are also finding is that not all virtual
colonoscopies are created equal. By that I mean that it needs to be
done at centers that have done a certain number; they need to have
a certain level of experience. We are also finding that
radiologists need to be specially trained in order to interpret the
CT scan images, and you need to have the very high powered, very
sophisticated software, that can basically take the CT scans and
turn them into images much as you would see with a
colonoscopy. While there will be reports that everyone can do
them, I think it is still not ready for primetime for all community
centers.
Foss
So most of us will probably still have a basic colonoscopy.
If a diagnosis of cancer is made on a colonoscopy, can you take us
step-by-step through what happens after that?
Chu
It is important to note why a colonoscopy is so important. It can
visualize polyps, and if polyps are seen they typically are
removed. That is important because we now know with about 20 to 25
years worth of research that colon cancer arises from polyps, so if
the colonoscopy can basically remove the polyps, in essence you
remove one of the main causes for developing colon cancer.
The other thing is that if in fact a colon cancer is present, the
hope is that the colonoscopy is catching it at an earlier stage. We
now know that when colon cancer is found and detected at the
earlier stages, we can cure up to 90% of those patients.
Foss
What percent of patients actually have early stage disease when
they are diagnosed?
Chu
I would say probably somewhere between 25% and 40% are actually
diagnosed with early stage colon cancer.
Foss
Let's step back a minute and talk a little bit
about the symptoms. We talked about the screening process
with colonoscopy, but what symptoms would a patient who has colon
cancer experience?
Chu
The classic symptoms are a change in bowel habits; there may be a
change in the color, typically we ask if there is blood in the
stool or if the stool has changed to kind of a tarry black
color. There can also be a change in the size, shape, and
caliber of the stools. The classic shape is actually pencil
thin stools. There can also be associated abdominal cramps, a
little bit of bloating, change in appetite, reduced appetite with
weight loss, and sometimes it is generalized fatigue. So
those are the classic symptoms. But again, to stress the
critical importance of screening, a good number of patients who
receive a diagnosis of colon cancer have absolutely no symptoms and
so that can be very misleading to an individual. They think
that if they do not have symptoms, there is no need to get
screening done, and that is absolutely wrong.
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Foss
That points out the critical need for us to follow the
recommendations in terms of screening. You mentioned that if you
have a family history that you need to be screened more often, but
for the average person age 50 and over, can you quickly reiterate
how often a patient needs to get a screening colonoscopy?
Chu
For an average risk individual, someone who does not have a prior
history of colon cancer, prior history of polyps, or a family
history of colon cancer and other cancers, they should have a
colonoscopy once they turn 50. If that is completely
negative, probably the next time you need to get a repeat
colonoscopy is 10 years later.
Foss
Thank you very much for this information. We will be back in
a few minutes to talk a little bit more about the treatment for
colon caner. You are listening to Yale Cancer Center Answers
and we are here discussing colorectal cancer with Dr. Ed Chu.
Foss
Welcome back to Yale Cancer Center Answers, this is Dr. Francine
Foss and I am joined by my co-host Dr. Ed Chu discussing treatment
options for colorectal cancer. Ed, we talked a little bit
about the risk factors for colorectal cancer, but I am wondering,
is there a difference in the incidence of this cancer in men versus
women, or are there any differences between different races?
Chu
I am glad you asked that question Francine. What we found
over the years is that the incidence in colon cancer is absolutely
the same between males and females. If you look at how many
men, and how many women get screened for colon cancer, women get
screened about half as frequently as men. The reason for that is
that there is this misperception that women are at a much lower
risk for developing colon cancer than their male counterparts, but
that absolutely is incorrect. Also, I think what typically
happens is that their primary care
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physicians and gynecological physicians obviously focus on breast
cancer and cervical cancer, for which we also have good screening
techniques, but the key is that women should get screening just
like men. With respect to race there is also some very
interesting new data coming out suggesting that African-Americans
seem to develop colon cancer at an earlier age than their Caucasian
counterparts. And when they do present they also tend to present
with more aggressive disease. Therefore, the American College
of Gastroenterology and the American Cancer Society have suggested
that African-Americans start screening at least 5 years earlier
than the magic number that we have been talking about which is
50. So, in general, African-Americans probably should start
at 45, but perhaps maybe even as early as age 40.
Foss
Can you address the question of diet and colon cancer and colon
cancer prevention? We have all been told that if we eat high fiber
and bulky type diets that would prevent colon caner.
Chu
There is no question that diet is an important risk factor for
developing colon cancer, and diets that are rich in fatty foods,
red meats, and low in fiber content does increase the risk of colon
cancer. Probably the best evidence for this is when you look at
individuals who grow up in Africa and in Asia where typically they
have a diet that is very rich in fiber, and fruits and vegetables;
the incidence of colon cancer is much lower. In this country
there have been a number of studies to try to address the question
of whether or not a diet that is rich in fiber and fruits and
vegetables can reduce the incidence of polyps and colon
cancer. The studies, unfortunately, have been all negative,
but I think the problem is that those studies only go on for about
a year or two and the damage has already been done, especially if
patients on these trials are say age 50 or older. The key is
to try to do these dietary interventions as early as possible.
Foss
What about calcium and vitamin D?
Chu
There is some very interesting data that calcium, vitamin D
supplementation, and also folic acid supplementation, may reduce
the risk of developing colon cancer.
Foss
Do you have a recommendation for patients who might be at high
risk, such as those who have a family history of colon cancer?
Chu
What I generally recommend is to focus on a diet that is rich in
lean meats, white meats, high in fiber, fruits and vegetables, and
try to avoid alcohol because alcohol seems to increase the
potential risk for developing colon cancer. Also, abstain from
smoking, and to live a good natural lifestyle, try to have daily
exercise. The recommendations that are given by the ACS
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for good healthy living, and to prevent other cancers, also hold
true for trying to prevent colon cancer.
Foss
Can you talk a little bit with us about patients who have colon
cancer? What has changed in the treatment of colon cancer over the
last 10 or 15 years?
Chu
There have been a number of major advances. The first one is
that we now know that this is a disease that requires a
multidisciplinary team to approach each individual patient and then
come up with treatment recommendations. As part of that
multidisciplinary team it is critically important to have a medical
oncologist, a surgical oncologist, and a radiation oncologist, each
of whom specializes in the treatment of colorectal cancer.
When I think back to when we were fellows at the National Cancer
Institute, back in the 1980s, for colon cancer we had only one drug
and that drug was 5-fluorouracil; basically we had that drug for
about 40 years and nothing else. Within the last 8 to 10
years we have three new, what are called, anticancer drugs that can
be used to treat colon cancer, and we have three new target agents
that can also be used to treat colon cancer. So, the
availability of new agents and new treatment regimens to treat both
early stage colon cancer and metastatic colon cancer has really
exploded.
Foss
Ed, I know that you are very intimately involved in the
Developmental Therapeutics Program and in developing novel
therapies for colon cancer. Can you tell us a little bit about what
you have been doing?
Chu
I would be very happy to. We have a very interesting agent,
in fact it is a Chinese herbal medicine called PHY906 that my close
colleague, Professor Tommy Cheng who has been on the show
previously to talk about this, first identified a few years ago.
Interestingly enough this herb has been used in the Orient for
nearly 2000 years to treat everyday nausea, vomiting, abdominal
cramps, and diarrhea. Our thinking was that since most of the
cancer drugs that we use to treat colon cancer have as their main
side effects nausea, vomiting, and diarrhea, wouldn't it be
interesting to see if could combine this herb with our traditional
chemotherapy. In fact, we actually did a study about three
years ago testing this herb in combination with a drug called
irinotecan, and really, not to our surprise, this herb
significantly protected against nausea, vomiting, and diarrhea. Our
colleague Dr. Wasif Saif, who is co-Director of our GI program at
Yale Cancer Center, just started a phase I/II study looking at this
herb in combination with this drug irinotecan in patients who have
been previously treated with other chemotherapy.
Foss
How does a patient get access to this kind of a new treatment?
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Chu
I think the best thing is for patients to go to the Yale Cancer
Center website which is www.yalecancercenter.org.
There they can click on to our website and go to either the
Developmental Therapeutics Program or the GI team. If someone wants
to get in contact with me directly, they can call my office at
203-785-6879.
Foss
Ed, we talked a little bit about some of the treatments that
patients are getting and I think you bring up a very important
point, which is the importance of symptomatic control and looking
at side effects of treatments and addressing what is important for
a patient as they go through the treatment for a disease like colon
cancer. Can you talk a little bit about what kind of treatment the
average patient would get if they need chemotherapy, how long that
would last, and what happens after they finish chemotherapy?
How often do they need to come back and get screened?
Chu
As I said, one of the great advances that we have seen in 2008-2009
is the amazing number of treatment options that are available to
patients. Typically it would involve a combination of the
traditional chemotherapy as well as incorporating one of these new
target therapies. Typically what we would do is we would start a
regimen, follow that patient for two to three months, see how they
are doing and how they are tolerating it, and also look at how the
tumor is responding. If in fact the tumor is showing a nice
response, and the patient is not experiencing any adverse side
effects, we would continue for another two to three months, and we
would continue until there is either evidence of the tumor no
longer responding, or at anytime the patient says they are just
experiencing too many side effects. One of the really
significant advances that we have seen is that many years ago, with
that one drug, 5-fluorouracil, we were talking about a median
overall survival of only about 10-12 months. Now, with very
aggressive treatments and sequential treatments and very effective
salvage treatments, we are now talking about survivals approaching
28 to 30 months; in some cases 3 years. We have really seen a
pretty significant prolongation in survival of patients who have
colon cancer that has spread throughout the body, and that is why
it is particularly important to not only give these very effective,
active therapies, but also try to maintain their quality of life.
What we want patients to do, and I know it is the same way in your
area of expertise, is try to maintain as best as possible their
normal activities of daily living and maintain their quality of
life.
Foss
You make a very good point here, and I think it is important to
stress this point to patients. I remember back, as you said,
5-10 years ago when patients with metastatic colon cancer had a
very bad prognosis. Because of some of the recent advances
that you mentioned, these patients can have a meaningful survival
and can live a couple of years with their disease, maybe even
longer in some cases. I think it is important for patients to
start thinking about
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the positive aspects of some of these new developments in therapy, and with regard to that, I would like to switch gears and talk about biological therapy. We talk a lot about biological treatments in the context of lymphomas and breast cancer, but I am just wondering if there are biological therapies for colon cancer as well?
Chu
As it turns out there are three new biologic target therapies.
These are antibodies that target key pathways that we now know are
critical for the growth of colon cancer. There is one drug called
Avastin which targets the VEGF signaling pathway, and we feel that
this pathway is important for angiogenesis, which is critical for
the growth and proliferation of tumors. There are other antibodies
that target a growth factor receptor called the epidermal growth
factor receptor, which we also know is critical for the growth and
proliferation of colon tumors.
Foss
Are there clinical trials at Yale Cancer Center looking at some of
these novel agents?
Chu
Yes, in fact we have studies looking at those antibodies in
combination with newer antibodies and newer target therapies
because one of the challenges with treating colon cancer, and other
cancers, is that not only can we inhibit those pathways, we need to
make sure we can inhibit other pathways that contribute to the
growth of colon cancer tumors.
Foss
Thank you very much. This was a very informative
program. You have been listening to Yale Cancer Center
Answers. I would like to thank my co-host and this week's guest Dr.
Ed Chu for joining me. Until next time, I am Dr. Francine
Foss from Yale Cancer Center wishing you a safe and healthy
week.
If you have questions or would like to share your comments, go to yalecancercenter.org where you can also subscribe to our podcast and find written transcripts of past programs. I am Bruce Barber and you are listening to the WNPR Health Forum from Connecticut Public Radio.