Colorectal Cancer Issues: An Update with Doctors Michael Wong and Charles Brown

Last Editorial Review: 10/23/2003

WebMD Live Events Transcript

Doctors Michael Wong and Charles Brown discuss issues concerning new methods of detecting and treating colorectal cancer.

The opinions expressed herein are the guests' alone and have not been reviewed by a WebMD physician. If you have questions about your health, you should consult your personal physician. This event is meant for informational purposes only.

Moderator: Welcome to WebMD Live. Today we will be discussing Colorectal Cancer Issues: An Update with Michael K.K. Wong, M.D., Ph.D., F.R.C.P.C., and Charles K. Brown, M.D., Ph.D.

Charles K. Brown, M.D., Ph.D., is an NIH-funded biologic therapy fellow at the University of Pittsburgh. He is also currently working with Dr. Michael Wong in the research of molecular angiogenesis at the University of Pittsburgh Cancer Institute. Brown is widely published and is the recipient of numerous awards, including the Ethicon Endo-Surgery Education Grant Award in Gastrointestinal Endoscopy and Laparoscopy and the Walt Oppelt Memorial Award for Excellence in Pharmacology and Therapeutics. His professional activities include the American College of Surgeons Candidate Group and the Commissioned Officers Association of the U.S. Public Health Service. His current research involves investigating the binding of ligopeptides with tumor-derived endothelial cells.

Michael K.K. Wong, M.D., Ph.D., F.R.C.P.C., is an assistant professor of medicine at the University of Pittsburgh/UPMC Health System. He is also affiliated with the University of Pittsburgh Cancer Institute. Extensively published, Wong is the recipient of numerous honors, including the National Cancer Institute of Canada's post-M.D. fellowship. His professional activities include the American Society for Cancer Research and the Royal College of Physicians and Surgeons of Canada. Wong's current clinical research focuses on molecular angiogenesis.

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Dr. Brown, Dr. Wong, welcome back to WebMD Live.

Dr. Wong: Thank you.

Dr. Brown: Thank you.

Moderator: What is the colon, and how does it work within the digestive system?

Dr. Brown: The colon is essentially the last portion of the digestive system and of the alimentary tract. It functions to reabsorb water from the digested material that has passed through the small intestine. Also waste elimination and waste storage.

Moderator: What is colorectal cancer?

Dr. Wong: The colon is lined by colorectal cells and what cancer is, is basically a uncontrolled growth of these cells. And these cells are malignant and what that means is they grow without respect to any borders and that's why they can go right through the colon and into the neighboring structures into the abdominal cavity. They can also break off and go to other parts of the body, known as metastasis.

Moderator: What causes colorectal cancer?

Dr. Brown: There are many causes for colorectal cancer. The main associated risk is a high fat, low fiber diet. There are also other individuals who are at risk for colon cancer, including those with a family history of colon cancer. Other risk factors include age and that is because your risk of colon cancer increases as your age increases. There's people with a history of polyps also are at risk. Finally people with a history of inflammatory bowel disease also known as ulcerative colitis are also at risk. The other large category of individuals that are also at significant risk are those that can inherit a genetic defect which puts them at high risk to develop colon cancer in their lifetime. These are known as FAT and HNPCC which are short forms that stand for two types of hereditary genetic diseases.

Moderator: What can people do to prevent these types of digestive health problems?

Dr. Brown: I think the best prevention that has been advocated by the health professionals is a low fat, high fiber diet. We cannot stress enough the importance of this particular aspect of the diet in preventing colon cancer. What we're really talking about is changing your lifestyle and an example of that is eating at least five servings of fruits and vegetables a day. A serving is like a banana or an orange or an apple or a full cup of lettuce.

Moderator: What are some of the warning signs of colorectal cancer?

Dr. Brown: Most of the time there are no real warning signs. Most colon cancers are silent. There are some symptoms that people have reported such as blood found in the stool. There are also changes in bowel habits and also changes in the consistency of the stool. These have been reported as signs associated with colon cancer. The most common sign and symptom is no symptom at all. It is important to stress routine screening for people who are at risk for colon cancer.

Moderator: Starting at what age?

Dr. Brown: We recommend starting at age 50. This is the population that Dr. Wong had stated previously as being one of the populations that is at risk for developing colon cancer. There are certain situations where we ought to pay attention to screen earlier and especially in people who have a family history of colon cancer.

Dr. Wong: ...when it is important to look carefully and screen earlier. People with a personal medical history, for example, women with history of cancer with ovary, uterus or breast, has a somewhat increased chance of subsequently developing colorectal cancer. Another group we might want to screen earlier is someone who has inflammatory bowel disease or someone who has history of colorectal cancer. Those patients we tend to watch more carefully.

Moderator: Is there a difference between colon cancer and colorectal cancer?

Dr. Brown: In general, colorectal cancer is the more accurate name for colon cancer. The colon really is divided into two parts, the rectum and large intestine. So colorectal cancer is the proper name and colon cancer is the lay person's name for it.

Moderator: How common is this type of cancer?

Dr. Wong: It's actually very common. Colon cancer is the fourth most commonly diagnosed cancer in the U.S. It will strike somewhere around 130,000 men and women each year according to the American Cancer Society. Amongst people with cancer, it is the second leading cause of cancer deaths. That means that it is a significant problem. In the next twelve months, somewhere in the neighborhood of 55,000 Americans, 1/4 of them under the age of 50, will die of colorectal cancer.

Moderator: What are the symptoms of a digestive health problem?

Dr. Wong: What I see commonly in my clinic can be as vague as stomach pains, abdominal discomfort. Some of my patients come in with tiredness, fatigue, a significant weight loss and so it can be fairly vague. There are other signs of diarrhea and constipation but, in general, just specific digestive symptoms is really not a good ruler to measure an individual who may or may not be at risk for colon cancer. I don't believe that any of them are good, reliable indicators.

Moderator: Are men or women more likely to get colorectal cancer? Why?

Dr. Brown: The statistics right now is that men are more likely to get colon cancer at a prevalence in the population that for every 3 men with colon cancer, 2 women will have colon cancer. Why this is the case, I don't think anyone knows.

Moderator: What age group is more likely to get colorectal cancer? Why?

Dr. Wong: Since it parallels our recommendations for screening, your chance of getting colon cancer increases as you age and it looks like the risk rises significantly after the age of 50.

Dr. Brown: 90% of all colon cancers occur in people over the age of 50.

Moderator: Is colorectal cancer often misdiagnosed?

Dr. Wong: I wouldn't call it misdiagnosed as much as not picked up or not paid attention to. I think Dr. Brown has said that the symptoms can be extremely vague and oftentimes, we see patients who really have no hint of a problem. An example is, I saw patient recently who was a marathon runner and his first hint of something wrong was that his time in a marathon was a bit off. In his case, his symptoms were extremely vague and this is not at all uncommon.

Moderator: Are there different stages of colorectal cancer, and how does the disease progress?

Dr. Brown: Yes, there are. Essentially there are four stages of colon cancer. Stage one is colon cancer that involves the innermost lining of the colon. Stage two involves the wall, the lining and the wall of the colon (muscular wall). Stage three is when the colon cancer has extended into the lymph nodes. Stage four is the most advanced stage and is where the colon cancer has appeared in other organs such as the liver or the lungs and this is what we call metastatic disease.

Moderator: What do colon cancer survivors have in common? Is there a common denominator?

Dr. Brown: If I understood the question, most colon cancer survivors have early stage colon cancer. That's an indicator, prognostic indicator of what the survivability will be. There have also been other what we call blood test markers that tells us whether the outcome is going to be better or not, and one of the markers is a marker called CEA. It stands for carcino embryonic antigens, where people with very high CEA at the presentation of the disease tend to have worse outcomes.

Dr. Wong: The earlier we catch the disease, the better off patients are. When the disease develops, one of the things I've noticed is that if their general health is fairly good to begin with, that usually bodes an encouraging outcome after treatment. I believe what Dr. Brown said about the CEA is nothing more than a reflection of how much cancer a person has, which brings us back to the first point. That is, the earlier, the better. That's where screening comes in.

Moderator: What is a polyp?

Dr. Brown: A polyp is an abnormal growth from the lining of the colon. It tends to be a benign process but can lead to malignant changes and the initiation of colon cancer.

Moderator: What different kinds of polyps are there?

Dr. Wong: Yes there are. In essence, there are many terms that we use to describe them. I think the most important thing about polyps is that many of them are benign but it important to find them because a significant portion of them, if left alone over the next many years (5, 8m 10 years) can become malignant. Polyps may represent some of the earliest changes in cancer. Therefore, one of the things that we recommend is that polyps should be removed and examined under the microscope.

Dr. Brown: In regard to the names or the different types of polyps, there are really two types. One is tubular adenoma and the other type is billous adenoma. The billous type tends to be flat and plastered against the lining of the colon while the tubular type tends to be round and hangs off the lining of the colon with a stalk. The other major difference between the two is that the billous types tend to have a higher chance of having cancer cells already in them. As physicians, we tend to pursue the billous type much more aggressively than the tubular type of polyps.

Moderator: How does a doctor screen for colorectal cancer?

Dr. Wong: There are several ways of doing it. The easiest way is to do what's called the fecal occult blood test. What that is, is that we're looking for blood in a stool and the reason for that is that colorectal cancers tend to bleed. The occult blood test is used to detect small amounts of bleeding. The other ways include a Sigmoidoscopy and what that entails is using a lighted instrument to examine the rectum and the lower part of the colon. Another way is to use colonoscopy and this is a more extensive test where a lighted instrument is used to examine not just the rectum but the entire colon. Another test is what's called a double contract barium enema. What that is is that a patient receives an enema with a barium containing solution and this coats the colon and the rectum and an x-ray is taken. We can see the outline of the colon remembering that colorectal cancer is a disease of the lining of the colon. Finally, something that's important is a digital rectal exam and what that means is that a physician with a gloved finger does a rectal exam and that's important because a significant portion of colorectal cancer occurs within reach of this examination. It is something that is easily done and which should be part of an annual physical exam.

Dr. Brown: In regard to the frequency of how these tests should be performed, the recommendation right now is digital rectal exam (DRE) and fecal occult blood test to be performed simultaneously every six months after the age of 50.

Dr. Wong: It is important to realize that not all tumors bleed and therefore, we have to pay particular attention to fecal occult blood tests and a negative test only means that we should pay attention to make sure we haven't missed a tumor that just happens not to be bleeding at that time. The reason why I mention this is because it is something I see in my own clinical practice that people who have a negative test sometimes let down their guard a little bit and it's important to realize that this is one disease where a fair degree of vigilance is important.

Dr. Brown: As for the frequency of Sigmoidoscopy, the current recommendation is to have that done at two year intervals starting at the age of 50.

Dr. Wong: I want to underline that what we're talking about here is screening in those people who don't have any special risk factors like we described earlier in this program. In those with risk factors, the most important thing is to develop a plan of action with their own physician given that they are at higher risk.

Moderator: Lets talk about treatment...

Dr. Brown: The most common form of treatment for colon cancer is surgery to remove the cancer. Dependent on the stage of the cancer at the time the patient presents with the disease, addition of chemotherapy or radiation therapy may also be rendered.

Dr. Wong: Another way of treating colon cancer especially in more advanced stages is to use chemotherapy. Chemotherapy is used sometimes immediately after surgery to help prevent cancers from coming back later on in a patient's lifetime. This type of chemotherapy treatment is called adjuvant ... adjuvant chemotherapy treatment. What that means is that we are giving chemotherapy, medication intravenously, in a situation where a surgeon has completely removed the tumor and the reason why we do adjuvant treatment is that there are certain situations where we know that the cancer has a high likelihood of coming back again in other places even after successful removal of the primary tumor. An example of this is when we find that a tumor has extended right through the bowel wall and has come to involve lymph nodes. I should mention that lymph nodes are small bean sized, nodes that capture the malignant cancer cells as they escape from the colon itself. In those situations, we find that these patients have a very high likelihood of cancer coming back and we would offer them treatment with chemotherapy to reduce the risk of that happening in the future. Finally the other situation where we use chemotherapy is where we have disease coming back elsewhere, liver or lung. When it has escaped or metastasized to too many places, then using intravenous treatment is the treatment of choice. There are situations where surgery may also be used again.

Dr. Brown: In specific instances in which the disease has recurred in another organ such as the liver or the lungs, surgery can sometimes still be offered to these patients to remove those recurrent tumors in those organs and provide for a longer survival and sometimes even the cure of these patients. In regard to radiation therapy, this is frequently used when the colon cancer involves the rectum, where following surgery or sometimes before surgery, the radiation is given to the rectal area. There are other modalities for treatment of colon cancer which at this point are considered more experimental rather than the standard of care. One such therapy involves the realm of immunotherapy where, in this therapy, the physician aims to strengthen or to boost the patient's immune system for destruction of the tumor. This form of therapy is considered more of a trial or experimental therapy at this point in time although animal studies and clinical trials involving patients have shown efficacy.

Moderator: What do you see in the future for prevention and treatment of colorectal cancer?

Dr. Wong: There are several strategies which are just emerging into clinical use right now. Examples of these include the use of antibodies and these are specific molecules directed against specific molecule targets which are now coming into clinical trials, and the hope is that these types of therapy can attack the cancer cells specifically with the least amount of side effects. However, we probably won't know the answer to this for quite some time. The other strategy which has garnered a lot of attention is the use of anti-angiogenesis therapy. What that is, is therapy directed against the body's blood vessels which feed the tumor. The hope is that this strategy will basically strangle off the tumor from the blood supply it needs to grow and spread. And again, strategies directed at this are coming to the forefront. Finally one of the things that I've seen garner a lot of public attention comes from an observation made years ago that people who were taking aspirin had a lower risk of developing colon cancer. This idea has matured over a good number of years to the use of medications which act in a manner similar to aspirin to hopefully prevent colon cancer from developing. This strategy is named anti-COX-2. This last form of therapy -- the drug that falls into this category is called Celebrex, which is actually an agent being used to treat rheumatoid arthritis.

Dr. Brown: The National Cancer Institute has just approved a clinical trial looking at this agent with the specific aim to answer the question of whether it can help prevent onset of polyps or colon cancer in patients taking this drug on a prophylactic or prevention basis. I think this is an exciting trial because this trial differs from other trials in that this is a prevention trial rather than a trial to treat existing disease. There are two newer drugs that have also been proved by the FDA and the National Cancer Institute for clinical trial sin this country. One is called oxalipoatin and the other one is CTT-11. These drugs have been used in Europe and have been shown to have better effects on treatment of colon cancer than current drugs which are considered to be standard of care. They have just recently been approved for use in North America and we hope that these two drugs will be the new breakthrough drugs for treatment of colon cancer.

lennypo_WebMD Is Sigmoidoscopy painful and is a local or general anesthetic used?

Dr. Brown: It is painful. What we do is--it is uncomfortable--I want to rephrase what I just said, the procedure is uncomfortable but not painful although this interpretation can be subjective from patient to patient. What we do is we sedate the patient for these procedures with IV sedation to lessen discomfort. We do not use local anesthesia or general anesthesia for the procedure.

Dr. Wong: Being a medical oncologist, I see patients with advanced colon cancer and I can only say that the discomfort in this and any of the other screening procedures is well worth the benefit. is our general University of Pittsburgh, Cancer Institute.

Moderator: Doctors, thank you both very much for joining us today. Please join us again on Thursday at 7 p.m. EST here in the World Watch and Health News Auditorium when we discuss Fibromyalgia and the MindBodySpirit Connection, with William B. Salt II, M.D., and Edwin H. Season, M.D.

Dr. Brown: Thank you.

Dr. Wong: Thank you.

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